Merge branch 'credentials_refactoring' of github.com:jboeuf/grpc into credentials_refactoring

106 files changed, 1315 insertions, 1083 deletions

diff --git a/src/compiler/csharp_generator.cc b/src/compiler/csharp_generator.cc
index ac0fee1ec4..29c359c539 100644
--- a/src/compiler/csharp_generator.cc
+++ b/src/compiler/csharp_generator.cc
@@ -214,10 +214,10 @@ std::string GetMethodReturnTypeServer(const MethodDescriptor *method) {
   switch (GetMethodType(method)) {
     case METHODTYPE_NO_STREAMING:
     case METHODTYPE_CLIENT_STREAMING:
-      return "Task<" + GetClassName(method->output_type()) + ">";
+      return "global::System.Threading.Tasks.Task<" + GetClassName(method->output_type()) + ">";
     case METHODTYPE_SERVER_STREAMING:
     case METHODTYPE_BIDI_STREAMING:
-      return "Task";
+      return "global::System.Threading.Tasks.Task";
   }
   GOOGLE_LOG(FATAL)<< "Can't get here.";
   return "";
diff --git a/src/compiler/python_generator.cc b/src/compiler/python_generator.cc
index 59137e1c92..8e76e6dce6 100644
--- a/src/compiler/python_generator.cc
+++ b/src/compiler/python_generator.cc
@@ -182,18 +182,40 @@ bool GetModuleAndMessagePath(const Descriptor* type,
   return true;
 }
 
+// Get all comments (leading, leading_detached, trailing) and print them as a
+// docstring. Any leading space of a line will be removed, but the line wrapping
+// will not be changed.
+template <typename DescriptorType>
+static void PrintAllComments(const DescriptorType* desc, Printer* printer) {
+  std::vector<grpc::string> comments;
+  grpc_generator::GetComment(desc, grpc_generator::COMMENTTYPE_LEADING_DETACHED,
+                             &comments);
+  grpc_generator::GetComment(desc, grpc_generator::COMMENTTYPE_LEADING,
+                             &comments);
+  grpc_generator::GetComment(desc, grpc_generator::COMMENTTYPE_TRAILING,
+                             &comments);
+  if (comments.empty()) {
+    return;
+  }
+  printer->Print("\"\"\"");
+  for (auto it = comments.begin(); it != comments.end(); ++it) {
+    size_t start_pos = it->find_first_not_of(' ');
+    if (start_pos != grpc::string::npos) {
+      printer->Print(it->c_str() + start_pos);
+    }
+    printer->Print("\n");
+  }
+  printer->Print("\"\"\"\n");
+}
+
 bool PrintBetaServicer(const ServiceDescriptor* service,
                        Printer* out) {
-  grpc::string doc = "<fill me in later!>";
-  map<grpc::string, grpc::string> dict = ListToDict({
-        "Service", service->name(),
-        "Documentation", doc,
-      });
   out->Print("\n");
-  out->Print(dict, "class Beta$Service$Servicer(object):\n");
+  out->Print("class Beta$Service$Servicer(object):\n", "Service",
+             service->name());
   {
     IndentScope raii_class_indent(out);
-    out->Print(dict, "\"\"\"$Documentation$\"\"\"\n");
+    PrintAllComments(service, out);
     for (int i = 0; i < service->method_count(); ++i) {
       auto meth = service->method(i);
       grpc::string arg_name = meth->client_streaming() ?
@@ -202,6 +224,7 @@ bool PrintBetaServicer(const ServiceDescriptor* service,
                  "Method", meth->name(), "ArgName", arg_name);
       {
         IndentScope raii_method_indent(out);
+        PrintAllComments(meth, out);
         out->Print("context.code(beta_interfaces.StatusCode.UNIMPLEMENTED)\n");
       }
     }
@@ -211,16 +234,11 @@ bool PrintBetaServicer(const ServiceDescriptor* service,
 
 bool PrintBetaStub(const ServiceDescriptor* service,
                    Printer* out) {
-  grpc::string doc = "The interface to which stubs will conform.";
-  map<grpc::string, grpc::string> dict = ListToDict({
-        "Service", service->name(),
-        "Documentation", doc,
-      });
   out->Print("\n");
-  out->Print(dict, "class Beta$Service$Stub(object):\n");
+  out->Print("class Beta$Service$Stub(object):\n", "Service", service->name());
   {
     IndentScope raii_class_indent(out);
-    out->Print(dict, "\"\"\"$Documentation$\"\"\"\n");
+    PrintAllComments(service, out);
     for (int i = 0; i < service->method_count(); ++i) {
       const MethodDescriptor* meth = service->method(i);
       grpc::string arg_name = meth->client_streaming() ?
@@ -229,6 +247,7 @@ bool PrintBetaStub(const ServiceDescriptor* service,
       out->Print(methdict, "def $Method$(self, $ArgName$, timeout):\n");
       {
         IndentScope raii_method_indent(out);
+        PrintAllComments(meth, out);
         out->Print("raise NotImplementedError()\n");
       }
       if (!meth->server_streaming()) {
diff --git a/src/compiler/ruby_generator.cc b/src/compiler/ruby_generator.cc
index 5ac56ad289..936a186beb 100644
--- a/src/compiler/ruby_generator.cc
+++ b/src/compiler/ruby_generator.cc
@@ -98,8 +98,8 @@ void PrintService(const ServiceDescriptor *service, const grpc::string &package,
   out->Print("self.marshal_class_method = :encode\n");
   out->Print("self.unmarshal_class_method = :decode\n");
   std::map<grpc::string, grpc::string> pkg_vars =
-      ListToDict({"service.name", service->name(), "pkg.name", package, });
-  out->Print(pkg_vars, "self.service_name = '$pkg.name$.$service.name$'\n");
+      ListToDict({"service_full_name", service->full_name()});
+  out->Print(pkg_vars, "self.service_name = '$service_full_name$'\n");
   out->Print("\n");
   for (int i = 0; i < service->method_count(); ++i) {
     PrintMethod(service->method(i), package, out);
diff --git a/src/core/ext/client_config/resolver_registry.c b/src/core/ext/client_config/resolver_registry.c
index 07f29bcb27..e7a4abd568 100644
--- a/src/core/ext/client_config/resolver_registry.c
+++ b/src/core/ext/client_config/resolver_registry.c
@@ -47,7 +47,6 @@ static int g_number_of_resolvers = 0;
 static char *g_default_resolver_prefix;
 
 void grpc_resolver_registry_init(const char *default_resolver_prefix) {
-  g_number_of_resolvers = 0;
   g_default_resolver_prefix = gpr_strdup(default_resolver_prefix);
 }
 
@@ -57,6 +56,13 @@ void grpc_resolver_registry_shutdown(void) {
     grpc_resolver_factory_unref(g_all_of_the_resolvers[i]);
   }
   gpr_free(g_default_resolver_prefix);
+  // FIXME(ctiller): this should live in grpc_resolver_registry_init,
+  // however that would have the client_config plugin call this AFTER we start
+  // registering resolvers from third party plugins, and so they'd never show
+  // up.
+  // We likely need some kind of dependency system for plugins.... what form
+  // that takes is TBD.
+  g_number_of_resolvers = 0;
 }
 
 void grpc_register_resolver_type(grpc_resolver_factory *factory) {
diff --git a/src/core/ext/lb_policy/grpclb/load_balancer_api.c b/src/core/ext/lb_policy/grpclb/load_balancer_api.c
index 459d6d9954..59b89997dd 100644
--- a/src/core/ext/lb_policy/grpclb/load_balancer_api.c
+++ b/src/core/ext/lb_policy/grpclb/load_balancer_api.c
@@ -50,7 +50,7 @@ static bool decode_serverlist(pb_istream_t *stream, const pb_field_t *field,
   decode_serverlist_arg *dec_arg = *arg;
   if (dec_arg->first_pass != 0) { /* first pass */
     grpc_grpclb_server server;
-    if (!pb_decode(stream, grpc_lb_v0_Server_fields, &server)) {
+    if (!pb_decode(stream, grpc_lb_v1_Server_fields, &server)) {
       return false;
     }
     dec_arg->num_servers++;
@@ -61,7 +61,7 @@ static bool decode_serverlist(pb_istream_t *stream, const pb_field_t *field,
       dec_arg->servers =
           gpr_malloc(sizeof(grpc_grpclb_server *) * dec_arg->num_servers);
     }
-    if (!pb_decode(stream, grpc_lb_v0_Server_fields, server)) {
+    if (!pb_decode(stream, grpc_lb_v1_Server_fields, server)) {
       return false;
     }
     dec_arg->servers[dec_arg->i++] = server;
@@ -87,13 +87,13 @@ gpr_slice grpc_grpclb_request_encode(const grpc_grpclb_request *request) {
   pb_ostream_t outputstream;
   gpr_slice slice;
   memset(&sizestream, 0, sizeof(pb_ostream_t));
-  pb_encode(&sizestream, grpc_lb_v0_LoadBalanceRequest_fields, request);
+  pb_encode(&sizestream, grpc_lb_v1_LoadBalanceRequest_fields, request);
   encoded_length = sizestream.bytes_written;
 
   slice = gpr_slice_malloc(encoded_length);
   outputstream =
       pb_ostream_from_buffer(GPR_SLICE_START_PTR(slice), encoded_length);
-  GPR_ASSERT(pb_encode(&outputstream, grpc_lb_v0_LoadBalanceRequest_fields,
+  GPR_ASSERT(pb_encode(&outputstream, grpc_lb_v1_LoadBalanceRequest_fields,
                        request) != 0);
   return slice;
 }
@@ -109,7 +109,7 @@ grpc_grpclb_response *grpc_grpclb_response_parse(gpr_slice encoded_response) {
                              GPR_SLICE_LENGTH(encoded_response));
   grpc_grpclb_response *res = gpr_malloc(sizeof(grpc_grpclb_response));
   memset(res, 0, sizeof(*res));
-  status = pb_decode(&stream, grpc_lb_v0_LoadBalanceResponse_fields, res);
+  status = pb_decode(&stream, grpc_lb_v1_LoadBalanceResponse_fields, res);
   if (!status) {
     grpc_grpclb_response_destroy(res);
     return NULL;
@@ -132,7 +132,7 @@ grpc_grpclb_serverlist *grpc_grpclb_response_parse_serverlist(
   res->server_list.servers.funcs.decode = decode_serverlist;
   res->server_list.servers.arg = &arg;
   arg.first_pass = 1;
-  status = pb_decode(&stream, grpc_lb_v0_LoadBalanceResponse_fields, res);
+  status = pb_decode(&stream, grpc_lb_v1_LoadBalanceResponse_fields, res);
   if (!status) {
     grpc_grpclb_response_destroy(res);
     return NULL;
@@ -140,7 +140,7 @@ grpc_grpclb_serverlist *grpc_grpclb_response_parse_serverlist(
 
   arg.first_pass = 0;
   status =
-      pb_decode(&stream_at_start, grpc_lb_v0_LoadBalanceResponse_fields, res);
+      pb_decode(&stream_at_start, grpc_lb_v1_LoadBalanceResponse_fields, res);
   if (!status) {
     grpc_grpclb_response_destroy(res);
     return NULL;
diff --git a/src/core/ext/lb_policy/grpclb/load_balancer_api.h b/src/core/ext/lb_policy/grpclb/load_balancer_api.h
index 968f7d278a..71b5616d0c 100644
--- a/src/core/ext/lb_policy/grpclb/load_balancer_api.h
+++ b/src/core/ext/lb_policy/grpclb/load_balancer_api.h
@@ -37,7 +37,7 @@
 #include <grpc/support/slice_buffer.h>
 
 #include "src/core/ext/client_config/lb_policy_factory.h"
-#include "src/core/ext/lb_policy/grpclb/proto/grpc/lb/v0/load_balancer.pb.h"
+#include "src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -45,10 +45,10 @@ extern "C" {
 
 #define GRPC_GRPCLB_SERVICE_NAME_MAX_LENGTH 128
 
-typedef grpc_lb_v0_LoadBalanceRequest grpc_grpclb_request;
-typedef grpc_lb_v0_LoadBalanceResponse grpc_grpclb_response;
-typedef grpc_lb_v0_Server grpc_grpclb_server;
-typedef grpc_lb_v0_Duration grpc_grpclb_duration;
+typedef grpc_lb_v1_LoadBalanceRequest grpc_grpclb_request;
+typedef grpc_lb_v1_LoadBalanceResponse grpc_grpclb_response;
+typedef grpc_lb_v1_Server grpc_grpclb_server;
+typedef grpc_lb_v1_Duration grpc_grpclb_duration;
 typedef struct grpc_grpclb_serverlist {
   grpc_grpclb_server **servers;
   size_t num_servers;
diff --git a/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v0/load_balancer.pb.h b/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v0/load_balancer.pb.h
deleted file mode 100644
index 3599f881bb..0000000000
--- a/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v0/load_balancer.pb.h
+++ /dev/null
@@ -1,182 +0,0 @@
-/*
- *
- * Copyright 2016, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-/* Automatically generated nanopb header */
-/* Generated by nanopb-0.3.5-dev */
-
-#ifndef PB_LOAD_BALANCER_PB_H_INCLUDED
-#define PB_LOAD_BALANCER_PB_H_INCLUDED
-#include "third_party/nanopb/pb.h"
-#if PB_PROTO_HEADER_VERSION != 30
-#error Regenerate this file with the current version of nanopb generator.
-#endif
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/* Struct definitions */
-typedef struct _grpc_lb_v0_ClientStats {
-    bool has_total_requests;
-    int64_t total_requests;
-    bool has_client_rpc_errors;
-    int64_t client_rpc_errors;
-    bool has_dropped_requests;
-    int64_t dropped_requests;
-} grpc_lb_v0_ClientStats;
-
-typedef struct _grpc_lb_v0_Duration {
-    bool has_seconds;
-    int64_t seconds;
-    bool has_nanos;
-    int32_t nanos;
-} grpc_lb_v0_Duration;
-
-typedef struct _grpc_lb_v0_InitialLoadBalanceRequest {
-    bool has_name;
-    char name[128];
-} grpc_lb_v0_InitialLoadBalanceRequest;
-
-typedef PB_BYTES_ARRAY_T(64) grpc_lb_v0_Server_load_balance_token_t;
-typedef struct _grpc_lb_v0_Server {
-    bool has_ip_address;
-    char ip_address[46];
-    bool has_port;
-    int32_t port;
-    bool has_load_balance_token;
-    grpc_lb_v0_Server_load_balance_token_t load_balance_token;
-    bool has_drop_request;
-    bool drop_request;
-} grpc_lb_v0_Server;
-
-typedef struct _grpc_lb_v0_InitialLoadBalanceResponse {
-    bool has_client_config;
-    char client_config[64];
-    bool has_load_balancer_delegate;
-    char load_balancer_delegate[64];
-    bool has_client_stats_report_interval;
-    grpc_lb_v0_Duration client_stats_report_interval;
-} grpc_lb_v0_InitialLoadBalanceResponse;
-
-typedef struct _grpc_lb_v0_LoadBalanceRequest {
-    bool has_initial_request;
-    grpc_lb_v0_InitialLoadBalanceRequest initial_request;
-    bool has_client_stats;
-    grpc_lb_v0_ClientStats client_stats;
-} grpc_lb_v0_LoadBalanceRequest;
-
-typedef struct _grpc_lb_v0_ServerList {
-    pb_callback_t servers;
-    bool has_expiration_interval;
-    grpc_lb_v0_Duration expiration_interval;
-} grpc_lb_v0_ServerList;
-
-typedef struct _grpc_lb_v0_LoadBalanceResponse {
-    bool has_initial_response;
-    grpc_lb_v0_InitialLoadBalanceResponse initial_response;
-    bool has_server_list;
-    grpc_lb_v0_ServerList server_list;
-} grpc_lb_v0_LoadBalanceResponse;
-
-/* Default values for struct fields */
-
-/* Initializer values for message structs */
-#define grpc_lb_v0_Duration_init_default         {false, 0, false, 0}
-#define grpc_lb_v0_LoadBalanceRequest_init_default {false, grpc_lb_v0_InitialLoadBalanceRequest_init_default, false, grpc_lb_v0_ClientStats_init_default}
-#define grpc_lb_v0_InitialLoadBalanceRequest_init_default {false, ""}
-#define grpc_lb_v0_ClientStats_init_default      {false, 0, false, 0, false, 0}
-#define grpc_lb_v0_LoadBalanceResponse_init_default {false, grpc_lb_v0_InitialLoadBalanceResponse_init_default, false, grpc_lb_v0_ServerList_init_default}
-#define grpc_lb_v0_InitialLoadBalanceResponse_init_default {false, "", false, "", false, grpc_lb_v0_Duration_init_default}
-#define grpc_lb_v0_ServerList_init_default       {{{NULL}, NULL}, false, grpc_lb_v0_Duration_init_default}
-#define grpc_lb_v0_Server_init_default           {false, "", false, 0, false, {0, {0}}, false, 0}
-#define grpc_lb_v0_Duration_init_zero            {false, 0, false, 0}
-#define grpc_lb_v0_LoadBalanceRequest_init_zero  {false, grpc_lb_v0_InitialLoadBalanceRequest_init_zero, false, grpc_lb_v0_ClientStats_init_zero}
-#define grpc_lb_v0_InitialLoadBalanceRequest_init_zero {false, ""}
-#define grpc_lb_v0_ClientStats_init_zero         {false, 0, false, 0, false, 0}
-#define grpc_lb_v0_LoadBalanceResponse_init_zero {false, grpc_lb_v0_InitialLoadBalanceResponse_init_zero, false, grpc_lb_v0_ServerList_init_zero}
-#define grpc_lb_v0_InitialLoadBalanceResponse_init_zero {false, "", false, "", false, grpc_lb_v0_Duration_init_zero}
-#define grpc_lb_v0_ServerList_init_zero          {{{NULL}, NULL}, false, grpc_lb_v0_Duration_init_zero}
-#define grpc_lb_v0_Server_init_zero              {false, "", false, 0, false, {0, {0}}, false, 0}
-
-/* Field tags (for use in manual encoding/decoding) */
-#define grpc_lb_v0_ClientStats_total_requests_tag 1
-#define grpc_lb_v0_ClientStats_client_rpc_errors_tag 2
-#define grpc_lb_v0_ClientStats_dropped_requests_tag 3
-#define grpc_lb_v0_Duration_seconds_tag          1
-#define grpc_lb_v0_Duration_nanos_tag            2
-#define grpc_lb_v0_InitialLoadBalanceRequest_name_tag 1
-#define grpc_lb_v0_Server_ip_address_tag         1
-#define grpc_lb_v0_Server_port_tag               2
-#define grpc_lb_v0_Server_load_balance_token_tag 3
-#define grpc_lb_v0_Server_drop_request_tag       4
-#define grpc_lb_v0_InitialLoadBalanceResponse_client_config_tag 1
-#define grpc_lb_v0_InitialLoadBalanceResponse_load_balancer_delegate_tag 2
-#define grpc_lb_v0_InitialLoadBalanceResponse_client_stats_report_interval_tag 3
-#define grpc_lb_v0_LoadBalanceRequest_initial_request_tag 1
-#define grpc_lb_v0_LoadBalanceRequest_client_stats_tag 2
-#define grpc_lb_v0_ServerList_servers_tag        1
-#define grpc_lb_v0_ServerList_expiration_interval_tag 3
-#define grpc_lb_v0_LoadBalanceResponse_initial_response_tag 1
-#define grpc_lb_v0_LoadBalanceResponse_server_list_tag 2
-
-/* Struct field encoding specification for nanopb */
-extern const pb_field_t grpc_lb_v0_Duration_fields[3];
-extern const pb_field_t grpc_lb_v0_LoadBalanceRequest_fields[3];
-extern const pb_field_t grpc_lb_v0_InitialLoadBalanceRequest_fields[2];
-extern const pb_field_t grpc_lb_v0_ClientStats_fields[4];
-extern const pb_field_t grpc_lb_v0_LoadBalanceResponse_fields[3];
-extern const pb_field_t grpc_lb_v0_InitialLoadBalanceResponse_fields[4];
-extern const pb_field_t grpc_lb_v0_ServerList_fields[3];
-extern const pb_field_t grpc_lb_v0_Server_fields[5];
-
-/* Maximum encoded size of messages (where known) */
-#define grpc_lb_v0_Duration_size                 22
-#define grpc_lb_v0_LoadBalanceRequest_size       169
-#define grpc_lb_v0_InitialLoadBalanceRequest_size 131
-#define grpc_lb_v0_ClientStats_size              33
-#define grpc_lb_v0_LoadBalanceResponse_size      (165 + grpc_lb_v0_ServerList_size)
-#define grpc_lb_v0_InitialLoadBalanceResponse_size 156
-#define grpc_lb_v0_Server_size                   127
-
-/* Message IDs (where set with "msgid" option) */
-#ifdef PB_MSGID
-
-#define LOAD_BALANCER_MESSAGES \
-
-
-#endif
-
-#ifdef __cplusplus
-} /* extern "C" */
-#endif
-
-#endif
diff --git a/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v0/load_balancer.pb.c b/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c
index 9719673181..52e11c40bb 100644
--- a/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v0/load_balancer.pb.c
+++ b/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c
@@ -33,7 +33,7 @@
 /* Automatically generated nanopb constant definitions */
 /* Generated by nanopb-0.3.5-dev */
 
-#include "src/core/ext/lb_policy/grpclb/proto/grpc/lb/v0/load_balancer.pb.h"
+#include "src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h"
 
 #if PB_PROTO_HEADER_VERSION != 30
 #error Regenerate this file with the current version of nanopb generator.
@@ -41,54 +41,53 @@
 
 
 
-const pb_field_t grpc_lb_v0_Duration_fields[3] = {
-    PB_FIELD(  1, INT64   , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_Duration, seconds, seconds, 0),
-    PB_FIELD(  2, INT32   , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_Duration, nanos, seconds, 0),
+const pb_field_t grpc_lb_v1_Duration_fields[3] = {
+    PB_FIELD(  1, INT64   , OPTIONAL, STATIC  , FIRST, grpc_lb_v1_Duration, seconds, seconds, 0),
+    PB_FIELD(  2, INT32   , OPTIONAL, STATIC  , OTHER, grpc_lb_v1_Duration, nanos, seconds, 0),
     PB_LAST_FIELD
 };
 
-const pb_field_t grpc_lb_v0_LoadBalanceRequest_fields[3] = {
-    PB_FIELD(  1, MESSAGE , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_LoadBalanceRequest, initial_request, initial_request, &grpc_lb_v0_InitialLoadBalanceRequest_fields),
-    PB_FIELD(  2, MESSAGE , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_LoadBalanceRequest, client_stats, initial_request, &grpc_lb_v0_ClientStats_fields),
+const pb_field_t grpc_lb_v1_LoadBalanceRequest_fields[3] = {
+    PB_FIELD(  1, MESSAGE , OPTIONAL, STATIC  , FIRST, grpc_lb_v1_LoadBalanceRequest, initial_request, initial_request, &grpc_lb_v1_InitialLoadBalanceRequest_fields),
+    PB_FIELD(  2, MESSAGE , OPTIONAL, STATIC  , OTHER, grpc_lb_v1_LoadBalanceRequest, client_stats, initial_request, &grpc_lb_v1_ClientStats_fields),
     PB_LAST_FIELD
 };
 
-const pb_field_t grpc_lb_v0_InitialLoadBalanceRequest_fields[2] = {
-    PB_FIELD(  1, STRING  , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_InitialLoadBalanceRequest, name, name, 0),
+const pb_field_t grpc_lb_v1_InitialLoadBalanceRequest_fields[2] = {
+    PB_FIELD(  1, STRING  , OPTIONAL, STATIC  , FIRST, grpc_lb_v1_InitialLoadBalanceRequest, name, name, 0),
     PB_LAST_FIELD
 };
 
-const pb_field_t grpc_lb_v0_ClientStats_fields[4] = {
-    PB_FIELD(  1, INT64   , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_ClientStats, total_requests, total_requests, 0),
-    PB_FIELD(  2, INT64   , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_ClientStats, client_rpc_errors, total_requests, 0),
-    PB_FIELD(  3, INT64   , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_ClientStats, dropped_requests, client_rpc_errors, 0),
+const pb_field_t grpc_lb_v1_ClientStats_fields[4] = {
+    PB_FIELD(  1, INT64   , OPTIONAL, STATIC  , FIRST, grpc_lb_v1_ClientStats, total_requests, total_requests, 0),
+    PB_FIELD(  2, INT64   , OPTIONAL, STATIC  , OTHER, grpc_lb_v1_ClientStats, client_rpc_errors, total_requests, 0),
+    PB_FIELD(  3, INT64   , OPTIONAL, STATIC  , OTHER, grpc_lb_v1_ClientStats, dropped_requests, client_rpc_errors, 0),
     PB_LAST_FIELD
 };
 
-const pb_field_t grpc_lb_v0_LoadBalanceResponse_fields[3] = {
-    PB_FIELD(  1, MESSAGE , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_LoadBalanceResponse, initial_response, initial_response, &grpc_lb_v0_InitialLoadBalanceResponse_fields),
-    PB_FIELD(  2, MESSAGE , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_LoadBalanceResponse, server_list, initial_response, &grpc_lb_v0_ServerList_fields),
+const pb_field_t grpc_lb_v1_LoadBalanceResponse_fields[3] = {
+    PB_FIELD(  1, MESSAGE , OPTIONAL, STATIC  , FIRST, grpc_lb_v1_LoadBalanceResponse, initial_response, initial_response, &grpc_lb_v1_InitialLoadBalanceResponse_fields),
+    PB_FIELD(  2, MESSAGE , OPTIONAL, STATIC  , OTHER, grpc_lb_v1_LoadBalanceResponse, server_list, initial_response, &grpc_lb_v1_ServerList_fields),
     PB_LAST_FIELD
 };
 
-const pb_field_t grpc_lb_v0_InitialLoadBalanceResponse_fields[4] = {
-    PB_FIELD(  1, STRING  , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_InitialLoadBalanceResponse, client_config, client_config, 0),
-    PB_FIELD(  2, STRING  , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_InitialLoadBalanceResponse, load_balancer_delegate, client_config, 0),
-    PB_FIELD(  3, MESSAGE , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_InitialLoadBalanceResponse, client_stats_report_interval, load_balancer_delegate, &grpc_lb_v0_Duration_fields),
+const pb_field_t grpc_lb_v1_InitialLoadBalanceResponse_fields[3] = {
+    PB_FIELD(  2, STRING  , OPTIONAL, STATIC  , FIRST, grpc_lb_v1_InitialLoadBalanceResponse, load_balancer_delegate, load_balancer_delegate, 0),
+    PB_FIELD(  3, MESSAGE , OPTIONAL, STATIC  , OTHER, grpc_lb_v1_InitialLoadBalanceResponse, client_stats_report_interval, load_balancer_delegate, &grpc_lb_v1_Duration_fields),
     PB_LAST_FIELD
 };
 
-const pb_field_t grpc_lb_v0_ServerList_fields[3] = {
-    PB_FIELD(  1, MESSAGE , REPEATED, CALLBACK, FIRST, grpc_lb_v0_ServerList, servers, servers, &grpc_lb_v0_Server_fields),
-    PB_FIELD(  3, MESSAGE , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_ServerList, expiration_interval, servers, &grpc_lb_v0_Duration_fields),
+const pb_field_t grpc_lb_v1_ServerList_fields[3] = {
+    PB_FIELD(  1, MESSAGE , REPEATED, CALLBACK, FIRST, grpc_lb_v1_ServerList, servers, servers, &grpc_lb_v1_Server_fields),
+    PB_FIELD(  3, MESSAGE , OPTIONAL, STATIC  , OTHER, grpc_lb_v1_ServerList, expiration_interval, servers, &grpc_lb_v1_Duration_fields),
     PB_LAST_FIELD
 };
 
-const pb_field_t grpc_lb_v0_Server_fields[5] = {
-    PB_FIELD(  1, STRING  , OPTIONAL, STATIC  , FIRST, grpc_lb_v0_Server, ip_address, ip_address, 0),
-    PB_FIELD(  2, INT32   , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_Server, port, ip_address, 0),
-    PB_FIELD(  3, BYTES   , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_Server, load_balance_token, port, 0),
-    PB_FIELD(  4, BOOL    , OPTIONAL, STATIC  , OTHER, grpc_lb_v0_Server, drop_request, load_balance_token, 0),
+const pb_field_t grpc_lb_v1_Server_fields[5] = {
+    PB_FIELD(  1, STRING  , OPTIONAL, STATIC  , FIRST, grpc_lb_v1_Server, ip_address, ip_address, 0),
+    PB_FIELD(  2, INT32   , OPTIONAL, STATIC  , OTHER, grpc_lb_v1_Server, port, ip_address, 0),
+    PB_FIELD(  3, STRING  , OPTIONAL, STATIC  , OTHER, grpc_lb_v1_Server, load_balance_token, port, 0),
+    PB_FIELD(  4, BOOL    , OPTIONAL, STATIC  , OTHER, grpc_lb_v1_Server, drop_request, load_balance_token, 0),
     PB_LAST_FIELD
 };
 
@@ -102,7 +101,7 @@ const pb_field_t grpc_lb_v0_Server_fields[5] = {
  * numbers or field sizes that are larger than what can fit in 8 or 16 bit
  * field descriptors.
  */
-PB_STATIC_ASSERT((pb_membersize(grpc_lb_v0_LoadBalanceRequest, initial_request) < 65536 && pb_membersize(grpc_lb_v0_LoadBalanceRequest, client_stats) < 65536 && pb_membersize(grpc_lb_v0_LoadBalanceResponse, initial_response) < 65536 && pb_membersize(grpc_lb_v0_LoadBalanceResponse, server_list) < 65536 && pb_membersize(grpc_lb_v0_InitialLoadBalanceResponse, client_stats_report_interval) < 65536 && pb_membersize(grpc_lb_v0_ServerList, servers) < 65536 && pb_membersize(grpc_lb_v0_ServerList, expiration_interval) < 65536), YOU_MUST_DEFINE_PB_FIELD_32BIT_FOR_MESSAGES_grpc_lb_v0_Duration_grpc_lb_v0_LoadBalanceRequest_grpc_lb_v0_InitialLoadBalanceRequest_grpc_lb_v0_ClientStats_grpc_lb_v0_LoadBalanceResponse_grpc_lb_v0_InitialLoadBalanceResponse_grpc_lb_v0_ServerList_grpc_lb_v0_Server)
+PB_STATIC_ASSERT((pb_membersize(grpc_lb_v1_LoadBalanceRequest, initial_request) < 65536 && pb_membersize(grpc_lb_v1_LoadBalanceRequest, client_stats) < 65536 && pb_membersize(grpc_lb_v1_LoadBalanceResponse, initial_response) < 65536 && pb_membersize(grpc_lb_v1_LoadBalanceResponse, server_list) < 65536 && pb_membersize(grpc_lb_v1_InitialLoadBalanceResponse, client_stats_report_interval) < 65536 && pb_membersize(grpc_lb_v1_ServerList, servers) < 65536 && pb_membersize(grpc_lb_v1_ServerList, expiration_interval) < 65536), YOU_MUST_DEFINE_PB_FIELD_32BIT_FOR_MESSAGES_grpc_lb_v1_Duration_grpc_lb_v1_LoadBalanceRequest_grpc_lb_v1_InitialLoadBalanceRequest_grpc_lb_v1_ClientStats_grpc_lb_v1_LoadBalanceResponse_grpc_lb_v1_InitialLoadBalanceResponse_grpc_lb_v1_ServerList_grpc_lb_v1_Server)
 #endif
 
 #if !defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT)
@@ -113,7 +112,7 @@ PB_STATIC_ASSERT((pb_membersize(grpc_lb_v0_LoadBalanceRequest, initial_request)
  * numbers or field sizes that are larger than what can fit in the default
  * 8 bit descriptors.
  */
-PB_STATIC_ASSERT((pb_membersize(grpc_lb_v0_LoadBalanceRequest, initial_request) < 256 && pb_membersize(grpc_lb_v0_LoadBalanceRequest, client_stats) < 256 && pb_membersize(grpc_lb_v0_LoadBalanceResponse, initial_response) < 256 && pb_membersize(grpc_lb_v0_LoadBalanceResponse, server_list) < 256 && pb_membersize(grpc_lb_v0_InitialLoadBalanceResponse, client_stats_report_interval) < 256 && pb_membersize(grpc_lb_v0_ServerList, servers) < 256 && pb_membersize(grpc_lb_v0_ServerList, expiration_interval) < 256), YOU_MUST_DEFINE_PB_FIELD_16BIT_FOR_MESSAGES_grpc_lb_v0_Duration_grpc_lb_v0_LoadBalanceRequest_grpc_lb_v0_InitialLoadBalanceRequest_grpc_lb_v0_ClientStats_grpc_lb_v0_LoadBalanceResponse_grpc_lb_v0_InitialLoadBalanceResponse_grpc_lb_v0_ServerList_grpc_lb_v0_Server)
+PB_STATIC_ASSERT((pb_membersize(grpc_lb_v1_LoadBalanceRequest, initial_request) < 256 && pb_membersize(grpc_lb_v1_LoadBalanceRequest, client_stats) < 256 && pb_membersize(grpc_lb_v1_LoadBalanceResponse, initial_response) < 256 && pb_membersize(grpc_lb_v1_LoadBalanceResponse, server_list) < 256 && pb_membersize(grpc_lb_v1_InitialLoadBalanceResponse, client_stats_report_interval) < 256 && pb_membersize(grpc_lb_v1_ServerList, servers) < 256 && pb_membersize(grpc_lb_v1_ServerList, expiration_interval) < 256), YOU_MUST_DEFINE_PB_FIELD_16BIT_FOR_MESSAGES_grpc_lb_v1_Duration_grpc_lb_v1_LoadBalanceRequest_grpc_lb_v1_InitialLoadBalanceRequest_grpc_lb_v1_ClientStats_grpc_lb_v1_LoadBalanceResponse_grpc_lb_v1_InitialLoadBalanceResponse_grpc_lb_v1_ServerList_grpc_lb_v1_Server)
 #endif
 
 
diff --git a/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h b/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h
new file mode 100644
index 0000000000..d5dc39ab94
--- /dev/null
+++ b/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h
@@ -0,0 +1,178 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+/* Automatically generated nanopb header */
+/* Generated by nanopb-0.3.5-dev */
+
+#ifndef PB_LOAD_BALANCER_PB_H_INCLUDED
+#define PB_LOAD_BALANCER_PB_H_INCLUDED
+#include "third_party/nanopb/pb.h"
+#if PB_PROTO_HEADER_VERSION != 30
+#error Regenerate this file with the current version of nanopb generator.
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Struct definitions */
+typedef struct _grpc_lb_v1_ClientStats {
+    bool has_total_requests;
+    int64_t total_requests;
+    bool has_client_rpc_errors;
+    int64_t client_rpc_errors;
+    bool has_dropped_requests;
+    int64_t dropped_requests;
+} grpc_lb_v1_ClientStats;
+
+typedef struct _grpc_lb_v1_Duration {
+    bool has_seconds;
+    int64_t seconds;
+    bool has_nanos;
+    int32_t nanos;
+} grpc_lb_v1_Duration;
+
+typedef struct _grpc_lb_v1_InitialLoadBalanceRequest {
+    bool has_name;
+    char name[128];
+} grpc_lb_v1_InitialLoadBalanceRequest;
+
+typedef struct _grpc_lb_v1_Server {
+    bool has_ip_address;
+    char ip_address[46];
+    bool has_port;
+    int32_t port;
+    bool has_load_balance_token;
+    char load_balance_token[64];
+    bool has_drop_request;
+    bool drop_request;
+} grpc_lb_v1_Server;
+
+typedef struct _grpc_lb_v1_InitialLoadBalanceResponse {
+    bool has_load_balancer_delegate;
+    char load_balancer_delegate[64];
+    bool has_client_stats_report_interval;
+    grpc_lb_v1_Duration client_stats_report_interval;
+} grpc_lb_v1_InitialLoadBalanceResponse;
+
+typedef struct _grpc_lb_v1_LoadBalanceRequest {
+    bool has_initial_request;
+    grpc_lb_v1_InitialLoadBalanceRequest initial_request;
+    bool has_client_stats;
+    grpc_lb_v1_ClientStats client_stats;
+} grpc_lb_v1_LoadBalanceRequest;
+
+typedef struct _grpc_lb_v1_ServerList {
+    pb_callback_t servers;
+    bool has_expiration_interval;
+    grpc_lb_v1_Duration expiration_interval;
+} grpc_lb_v1_ServerList;
+
+typedef struct _grpc_lb_v1_LoadBalanceResponse {
+    bool has_initial_response;
+    grpc_lb_v1_InitialLoadBalanceResponse initial_response;
+    bool has_server_list;
+    grpc_lb_v1_ServerList server_list;
+} grpc_lb_v1_LoadBalanceResponse;
+
+/* Default values for struct fields */
+
+/* Initializer values for message structs */
+#define grpc_lb_v1_Duration_init_default         {false, 0, false, 0}
+#define grpc_lb_v1_LoadBalanceRequest_init_default {false, grpc_lb_v1_InitialLoadBalanceRequest_init_default, false, grpc_lb_v1_ClientStats_init_default}
+#define grpc_lb_v1_InitialLoadBalanceRequest_init_default {false, ""}
+#define grpc_lb_v1_ClientStats_init_default      {false, 0, false, 0, false, 0}
+#define grpc_lb_v1_LoadBalanceResponse_init_default {false, grpc_lb_v1_InitialLoadBalanceResponse_init_default, false, grpc_lb_v1_ServerList_init_default}
+#define grpc_lb_v1_InitialLoadBalanceResponse_init_default {false, "", false, grpc_lb_v1_Duration_init_default}
+#define grpc_lb_v1_ServerList_init_default       {{{NULL}, NULL}, false, grpc_lb_v1_Duration_init_default}
+#define grpc_lb_v1_Server_init_default           {false, "", false, 0, false, "", false, 0}
+#define grpc_lb_v1_Duration_init_zero            {false, 0, false, 0}
+#define grpc_lb_v1_LoadBalanceRequest_init_zero  {false, grpc_lb_v1_InitialLoadBalanceRequest_init_zero, false, grpc_lb_v1_ClientStats_init_zero}
+#define grpc_lb_v1_InitialLoadBalanceRequest_init_zero {false, ""}
+#define grpc_lb_v1_ClientStats_init_zero         {false, 0, false, 0, false, 0}
+#define grpc_lb_v1_LoadBalanceResponse_init_zero {false, grpc_lb_v1_InitialLoadBalanceResponse_init_zero, false, grpc_lb_v1_ServerList_init_zero}
+#define grpc_lb_v1_InitialLoadBalanceResponse_init_zero {false, "", false, grpc_lb_v1_Duration_init_zero}
+#define grpc_lb_v1_ServerList_init_zero          {{{NULL}, NULL}, false, grpc_lb_v1_Duration_init_zero}
+#define grpc_lb_v1_Server_init_zero              {false, "", false, 0, false, "", false, 0}
+
+/* Field tags (for use in manual encoding/decoding) */
+#define grpc_lb_v1_ClientStats_total_requests_tag 1
+#define grpc_lb_v1_ClientStats_client_rpc_errors_tag 2
+#define grpc_lb_v1_ClientStats_dropped_requests_tag 3
+#define grpc_lb_v1_Duration_seconds_tag          1
+#define grpc_lb_v1_Duration_nanos_tag            2
+#define grpc_lb_v1_InitialLoadBalanceRequest_name_tag 1
+#define grpc_lb_v1_Server_ip_address_tag         1
+#define grpc_lb_v1_Server_port_tag               2
+#define grpc_lb_v1_Server_load_balance_token_tag 3
+#define grpc_lb_v1_Server_drop_request_tag       4
+#define grpc_lb_v1_InitialLoadBalanceResponse_load_balancer_delegate_tag 2
+#define grpc_lb_v1_InitialLoadBalanceResponse_client_stats_report_interval_tag 3
+#define grpc_lb_v1_LoadBalanceRequest_initial_request_tag 1
+#define grpc_lb_v1_LoadBalanceRequest_client_stats_tag 2
+#define grpc_lb_v1_ServerList_servers_tag        1
+#define grpc_lb_v1_ServerList_expiration_interval_tag 3
+#define grpc_lb_v1_LoadBalanceResponse_initial_response_tag 1
+#define grpc_lb_v1_LoadBalanceResponse_server_list_tag 2
+
+/* Struct field encoding specification for nanopb */
+extern const pb_field_t grpc_lb_v1_Duration_fields[3];
+extern const pb_field_t grpc_lb_v1_LoadBalanceRequest_fields[3];
+extern const pb_field_t grpc_lb_v1_InitialLoadBalanceRequest_fields[2];
+extern const pb_field_t grpc_lb_v1_ClientStats_fields[4];
+extern const pb_field_t grpc_lb_v1_LoadBalanceResponse_fields[3];
+extern const pb_field_t grpc_lb_v1_InitialLoadBalanceResponse_fields[3];
+extern const pb_field_t grpc_lb_v1_ServerList_fields[3];
+extern const pb_field_t grpc_lb_v1_Server_fields[5];
+
+/* Maximum encoded size of messages (where known) */
+#define grpc_lb_v1_Duration_size                 22
+#define grpc_lb_v1_LoadBalanceRequest_size       169
+#define grpc_lb_v1_InitialLoadBalanceRequest_size 131
+#define grpc_lb_v1_ClientStats_size              33
+#define grpc_lb_v1_LoadBalanceResponse_size      (98 + grpc_lb_v1_ServerList_size)
+#define grpc_lb_v1_InitialLoadBalanceResponse_size 90
+#define grpc_lb_v1_Server_size                   127
+
+/* Message IDs (where set with "msgid" option) */
+#ifdef PB_MSGID
+
+#define LOAD_BALANCER_MESSAGES \
+
+
+#endif
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif
diff --git a/src/core/ext/lb_policy/round_robin/round_robin.c b/src/core/ext/lb_policy/round_robin/round_robin.c
index 3f6051b892..dcdc0c6285 100644
--- a/src/core/ext/lb_policy/round_robin/round_robin.c
+++ b/src/core/ext/lb_policy/round_robin/round_robin.c
@@ -306,8 +306,10 @@ static void start_picking(grpc_exec_ctx *exec_ctx, round_robin_lb_policy *p) {
   size_t i;
   p->started_picking = 1;
 
-  gpr_log(GPR_DEBUG, "LB_POLICY: p=%p num_subchannels=%d", p,
-          p->num_subchannels);
+  if (grpc_lb_round_robin_trace) {
+    gpr_log(GPR_DEBUG, "LB_POLICY: p=%p num_subchannels=%d", p,
+            p->num_subchannels);
+  }
 
   for (i = 0; i < p->num_subchannels; i++) {
     subchannel_data *sd = p->subchannels[i];
diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.c b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
index 8c8593748d..b6886a2201 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
@@ -56,6 +56,8 @@
 #define DEFAULT_CONNECTION_WINDOW_TARGET (1024 * 1024)
 #define MAX_WINDOW 0x7fffffffu
 
+#define DEFAULT_MAX_HEADER_LIST_SIZE (16 * 1024)
+
 #define MAX_CLIENT_STREAM_ID 0x7fffffffu
 
 int grpc_http_trace = 0;
@@ -65,8 +67,8 @@ int grpc_flowctl_trace = 0;
   ((grpc_chttp2_transport *)((char *)(tw)-offsetof(grpc_chttp2_transport, \
                                                    writing)))
 
-#define TRANSPORT_FROM_PARSING(tw)                                        \
-  ((grpc_chttp2_transport *)((char *)(tw)-offsetof(grpc_chttp2_transport, \
+#define TRANSPORT_FROM_PARSING(tp)                                        \
+  ((grpc_chttp2_transport *)((char *)(tp)-offsetof(grpc_chttp2_transport, \
                                                    parsing)))
 
 #define TRANSPORT_FROM_GLOBAL(tg)                                         \
@@ -311,6 +313,8 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     push_setting(t, GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS, 0);
   }
   push_setting(t, GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE, DEFAULT_WINDOW);
+  push_setting(t, GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
+               DEFAULT_MAX_HEADER_LIST_SIZE);
 
   if (channel_args) {
     for (i = 0; i < channel_args->num_args; i++) {
@@ -378,6 +382,18 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
               &t->writing.hpack_compressor,
               (uint32_t)channel_args->args[i].value.integer);
         }
+      } else if (0 == strcmp(channel_args->args[i].key,
+                             GRPC_ARG_MAX_METADATA_SIZE)) {
+        if (channel_args->args[i].type != GRPC_ARG_INTEGER) {
+          gpr_log(GPR_ERROR, "%s: must be an integer",
+                  GRPC_ARG_MAX_METADATA_SIZE);
+        } else if (channel_args->args[i].value.integer < 0) {
+          gpr_log(GPR_ERROR, "%s: must be non-negative",
+                  GRPC_ARG_MAX_METADATA_SIZE);
+        } else {
+          push_setting(t, GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
+                       (uint32_t)channel_args->args[i].value.integer);
+        }
       }
     }
   }
@@ -510,7 +526,7 @@ static int init_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
                           [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
     *t->accepting_stream = s;
     grpc_chttp2_stream_map_add(&t->parsing_stream_map, s->global.id, s);
-    s->global.in_stream_map = 1;
+    s->global.in_stream_map = true;
   }
 
   grpc_chttp2_run_with_global_lock(exec_ctx, t, s, finish_init_stream_locked,
@@ -783,7 +799,8 @@ void grpc_chttp2_add_incoming_goaway(
     grpc_exec_ctx *exec_ctx, grpc_chttp2_transport_global *transport_global,
     uint32_t goaway_error, gpr_slice goaway_text) {
   char *msg = gpr_dump_slice(goaway_text, GPR_DUMP_HEX | GPR_DUMP_ASCII);
-  gpr_log(GPR_DEBUG, "got goaway [%d]: %s", goaway_error, msg);
+  GRPC_CHTTP2_IF_TRACING(
+      gpr_log(GPR_DEBUG, "got goaway [%d]: %s", goaway_error, msg));
   gpr_free(msg);
   gpr_slice_unref(goaway_text);
   transport_global->seen_goaway = 1;
@@ -833,7 +850,7 @@ static void maybe_start_some_streams(
     grpc_chttp2_stream_map_add(
         &TRANSPORT_FROM_GLOBAL(transport_global)->new_stream_map,
         stream_global->id, STREAM_FROM_GLOBAL(stream_global));
-    stream_global->in_stream_map = 1;
+    stream_global->in_stream_map = true;
     transport_global->concurrent_stream_count++;
     grpc_chttp2_become_writable(transport_global, stream_global);
   }
@@ -932,24 +949,38 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx,
     stream_global->send_initial_metadata_finished =
         add_closure_barrier(on_complete);
     stream_global->send_initial_metadata = op->send_initial_metadata;
-    if (contains_non_ok_status(transport_global, op->send_initial_metadata)) {
-      stream_global->seen_error = 1;
-      grpc_chttp2_list_add_check_read_ops(transport_global, stream_global);
-    }
-    if (!stream_global->write_closed) {
-      if (transport_global->is_client) {
-        GPR_ASSERT(stream_global->id == 0);
-        grpc_chttp2_list_add_waiting_for_concurrency(transport_global,
-                                                     stream_global);
-        maybe_start_some_streams(exec_ctx, transport_global);
+    const size_t metadata_size =
+        grpc_metadata_batch_size(op->send_initial_metadata);
+    const size_t metadata_peer_limit =
+        transport_global->settings[GRPC_PEER_SETTINGS]
+                                  [GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE];
+    if (metadata_size > metadata_peer_limit) {
+      gpr_log(GPR_DEBUG,
+              "to-be-sent initial metadata size exceeds peer limit "
+              "(%lu vs. %lu)",
+              metadata_size, metadata_peer_limit);
+      cancel_from_api(exec_ctx, transport_global, stream_global,
+                      GRPC_STATUS_RESOURCE_EXHAUSTED);
+    } else {
+      if (contains_non_ok_status(transport_global, op->send_initial_metadata)) {
+        stream_global->seen_error = true;
+        grpc_chttp2_list_add_check_read_ops(transport_global, stream_global);
+      }
+      if (!stream_global->write_closed) {
+        if (transport_global->is_client) {
+          GPR_ASSERT(stream_global->id == 0);
+          grpc_chttp2_list_add_waiting_for_concurrency(transport_global,
+                                                       stream_global);
+          maybe_start_some_streams(exec_ctx, transport_global);
+        } else {
+          GPR_ASSERT(stream_global->id != 0);
+          grpc_chttp2_become_writable(transport_global, stream_global);
+        }
       } else {
-        GPR_ASSERT(stream_global->id != 0);
-        grpc_chttp2_become_writable(transport_global, stream_global);
+        grpc_chttp2_complete_closure_step(
+            exec_ctx, stream_global,
+            &stream_global->send_initial_metadata_finished, 0);
       }
-    } else {
-      grpc_chttp2_complete_closure_step(
-          exec_ctx, stream_global,
-          &stream_global->send_initial_metadata_finished, 0);
     }
   }
 
@@ -973,19 +1004,34 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx,
     stream_global->send_trailing_metadata_finished =
         add_closure_barrier(on_complete);
     stream_global->send_trailing_metadata = op->send_trailing_metadata;
-    if (contains_non_ok_status(transport_global, op->send_trailing_metadata)) {
-      stream_global->seen_error = 1;
-      grpc_chttp2_list_add_check_read_ops(transport_global, stream_global);
-    }
-    if (stream_global->write_closed) {
-      grpc_chttp2_complete_closure_step(
-          exec_ctx, stream_global,
-          &stream_global->send_trailing_metadata_finished,
-          grpc_metadata_batch_is_empty(op->send_trailing_metadata));
-    } else if (stream_global->id != 0) {
-      /* TODO(ctiller): check if there's flow control for any outstanding
-         bytes before going writable */
-      grpc_chttp2_become_writable(transport_global, stream_global);
+    const size_t metadata_size =
+        grpc_metadata_batch_size(op->send_trailing_metadata);
+    const size_t metadata_peer_limit =
+        transport_global->settings[GRPC_PEER_SETTINGS]
+                                  [GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE];
+    if (metadata_size > metadata_peer_limit) {
+      gpr_log(GPR_DEBUG,
+              "to-be-sent trailing metadata size exceeds peer limit "
+              "(%lu vs. %lu)",
+              metadata_size, metadata_peer_limit);
+      cancel_from_api(exec_ctx, transport_global, stream_global,
+                      GRPC_STATUS_RESOURCE_EXHAUSTED);
+    } else {
+      if (contains_non_ok_status(transport_global,
+                                 op->send_trailing_metadata)) {
+        stream_global->seen_error = true;
+        grpc_chttp2_list_add_check_read_ops(transport_global, stream_global);
+      }
+      if (stream_global->write_closed) {
+        grpc_chttp2_complete_closure_step(
+            exec_ctx, stream_global,
+            &stream_global->send_trailing_metadata_finished,
+            grpc_metadata_batch_is_empty(op->send_trailing_metadata));
+      } else if (stream_global->id != 0) {
+        /* TODO(ctiller): check if there's flow control for any outstanding
+           bytes before going writable */
+        grpc_chttp2_become_writable(transport_global, stream_global);
+      }
     }
   }
 
@@ -1148,6 +1194,16 @@ static void check_read_ops(grpc_exec_ctx *exec_ctx,
       grpc_chttp2_list_pop_check_read_ops(transport_global, &stream_global)) {
     if (stream_global->recv_initial_metadata_ready != NULL &&
         stream_global->published_initial_metadata) {
+      if (stream_global->seen_error) {
+        while ((bs = grpc_chttp2_incoming_frame_queue_pop(
+                    &stream_global->incoming_frames)) != NULL) {
+          incoming_byte_stream_destroy_locked(exec_ctx, NULL, NULL, bs);
+        }
+        if (stream_global->exceeded_metadata_size) {
+          cancel_from_api(exec_ctx, transport_global, stream_global,
+                          GRPC_STATUS_RESOURCE_EXHAUSTED);
+        }
+      }
       grpc_chttp2_incoming_metadata_buffer_publish(
           &stream_global->received_initial_metadata,
           stream_global->recv_initial_metadata);
@@ -1177,10 +1233,15 @@ static void check_read_ops(grpc_exec_ctx *exec_ctx,
     }
     if (stream_global->recv_trailing_metadata_finished != NULL &&
         stream_global->read_closed && stream_global->write_closed) {
-      while (stream_global->seen_error &&
-             (bs = grpc_chttp2_incoming_frame_queue_pop(
-                  &stream_global->incoming_frames)) != NULL) {
-        incoming_byte_stream_destroy_locked(exec_ctx, NULL, NULL, bs);
+      if (stream_global->seen_error) {
+        while ((bs = grpc_chttp2_incoming_frame_queue_pop(
+                    &stream_global->incoming_frames)) != NULL) {
+          incoming_byte_stream_destroy_locked(exec_ctx, NULL, NULL, bs);
+        }
+        if (stream_global->exceeded_metadata_size) {
+          cancel_from_api(exec_ctx, transport_global, stream_global,
+                          GRPC_STATUS_RESOURCE_EXHAUSTED);
+        }
       }
       if (stream_global->all_incoming_byte_streams_finished) {
         grpc_chttp2_incoming_metadata_buffer_publish(
@@ -1212,7 +1273,7 @@ static void remove_stream(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     s = grpc_chttp2_stream_map_delete(&t->new_stream_map, id);
   }
   GPR_ASSERT(s);
-  s->global.in_stream_map = 0;
+  s->global.in_stream_map = false;
   if (t->parsing.incoming_stream == &s->parsing) {
     t->parsing.incoming_stream = NULL;
     grpc_chttp2_parsing_become_skip_parser(exec_ctx, &t->parsing);
@@ -1256,7 +1317,7 @@ static void cancel_from_api(grpc_exec_ctx *exec_ctx,
                             NULL);
   }
   if (status != GRPC_STATUS_OK && !stream_global->seen_error) {
-    stream_global->seen_error = 1;
+    stream_global->seen_error = true;
     grpc_chttp2_list_add_check_read_ops(transport_global, stream_global);
   }
   grpc_chttp2_mark_stream_closed(exec_ctx, transport_global, stream_global, 1,
@@ -1268,7 +1329,7 @@ void grpc_chttp2_fake_status(grpc_exec_ctx *exec_ctx,
                              grpc_chttp2_stream_global *stream_global,
                              grpc_status_code status, gpr_slice *slice) {
   if (status != GRPC_STATUS_OK) {
-    stream_global->seen_error = 1;
+    stream_global->seen_error = true;
     grpc_chttp2_list_add_check_read_ops(transport_global, stream_global);
   }
   /* stream_global->recv_trailing_metadata_finished gives us a
@@ -1292,7 +1353,7 @@ void grpc_chttp2_fake_status(grpc_exec_ctx *exec_ctx,
               GRPC_MDSTR_GRPC_MESSAGE,
               grpc_mdstr_from_slice(gpr_slice_ref(*slice))));
     }
-    stream_global->published_trailing_metadata = 1;
+    stream_global->published_trailing_metadata = true;
     grpc_chttp2_list_add_check_read_ops(transport_global, stream_global);
   }
   if (slice) {
@@ -1322,13 +1383,13 @@ void grpc_chttp2_mark_stream_closed(
   }
   grpc_chttp2_list_add_check_read_ops(transport_global, stream_global);
   if (close_reads && !stream_global->read_closed) {
-    stream_global->read_closed = 1;
-    stream_global->published_initial_metadata = 1;
-    stream_global->published_trailing_metadata = 1;
+    stream_global->read_closed = true;
+    stream_global->published_initial_metadata = true;
+    stream_global->published_trailing_metadata = true;
     decrement_active_streams_locked(exec_ctx, transport_global, stream_global);
   }
   if (close_writes && !stream_global->write_closed) {
-    stream_global->write_closed = 1;
+    stream_global->write_closed = true;
     if (TRANSPORT_FROM_GLOBAL(transport_global)->executor.writing_active) {
       GRPC_CHTTP2_STREAM_REF(stream_global, "finish_writes");
       grpc_chttp2_list_add_closed_waiting_for_writing(transport_global,
diff --git a/src/core/ext/transport/chttp2/transport/frame_rst_stream.c b/src/core/ext/transport/chttp2/transport/frame_rst_stream.c
index 22467e9ddd..7f01105e3e 100644
--- a/src/core/ext/transport/chttp2/transport/frame_rst_stream.c
+++ b/src/core/ext/transport/chttp2/transport/frame_rst_stream.c
@@ -45,15 +45,20 @@ gpr_slice grpc_chttp2_rst_stream_create(uint32_t id, uint32_t code,
   stats->framing_bytes += frame_size;
   uint8_t *p = GPR_SLICE_START_PTR(slice);
 
+  // Frame size.
   *p++ = 0;
   *p++ = 0;
   *p++ = 4;
+  // Frame type.
   *p++ = GRPC_CHTTP2_FRAME_RST_STREAM;
+  // Flags.
   *p++ = 0;
+  // Stream ID.
   *p++ = (uint8_t)(id >> 24);
   *p++ = (uint8_t)(id >> 16);
   *p++ = (uint8_t)(id >> 8);
   *p++ = (uint8_t)(id);
+  // Error code.
   *p++ = (uint8_t)(code >> 24);
   *p++ = (uint8_t)(code >> 16);
   *p++ = (uint8_t)(code >> 8);
diff --git a/src/core/ext/transport/chttp2/transport/hpack_encoder.c b/src/core/ext/transport/chttp2/transport/hpack_encoder.c
index 555027c866..ebeee37f0d 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_encoder.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_encoder.c
@@ -63,6 +63,8 @@
 /* don't consider adding anything bigger than this to the hpack table */
 #define MAX_DECODER_SPACE_USAGE 512
 
+extern int grpc_http_trace;
+
 typedef struct {
   int is_first_frame;
   /* number of bytes in 'output' when we started the frame - used to calculate
@@ -532,7 +534,9 @@ void grpc_chttp2_hpack_compressor_set_max_table_size(
     }
   }
   c->advertise_table_size_change = 1;
-  gpr_log(GPR_DEBUG, "set max table size from encoder to %d", max_table_size);
+  if (grpc_http_trace) {
+    gpr_log(GPR_DEBUG, "set max table size from encoder to %d", max_table_size);
+  }
 }
 
 void grpc_chttp2_encode_header(grpc_chttp2_hpack_compressor *c,
diff --git a/src/core/ext/transport/chttp2/transport/hpack_table.c b/src/core/ext/transport/chttp2/transport/hpack_table.c
index 4d64506de2..295f31c44f 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_table.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_table.c
@@ -253,7 +253,9 @@ void grpc_chttp2_hptbl_set_max_bytes(grpc_chttp2_hptbl *tbl,
   if (tbl->max_bytes == max_bytes) {
     return;
   }
-  gpr_log(GPR_DEBUG, "Update hpack parser max size to %d", max_bytes);
+  if (grpc_http_trace) {
+    gpr_log(GPR_DEBUG, "Update hpack parser max size to %d", max_bytes);
+  }
   while (tbl->mem_used > max_bytes) {
     evict1(tbl);
   }
diff --git a/src/core/ext/transport/chttp2/transport/incoming_metadata.c b/src/core/ext/transport/chttp2/transport/incoming_metadata.c
index db21744f0c..3e463a7995 100644
--- a/src/core/ext/transport/chttp2/transport/incoming_metadata.c
+++ b/src/core/ext/transport/chttp2/transport/incoming_metadata.c
@@ -65,6 +65,7 @@ void grpc_chttp2_incoming_metadata_buffer_add(
         gpr_realloc(buffer->elems, sizeof(*buffer->elems) * buffer->capacity);
   }
   buffer->elems[buffer->count++].md = elem;
+  buffer->size += GRPC_MDELEM_LENGTH(elem);
 }
 
 void grpc_chttp2_incoming_metadata_buffer_set_deadline(
diff --git a/src/core/ext/transport/chttp2/transport/incoming_metadata.h b/src/core/ext/transport/chttp2/transport/incoming_metadata.h
index 17ecf8e181..df4343b93e 100644
--- a/src/core/ext/transport/chttp2/transport/incoming_metadata.h
+++ b/src/core/ext/transport/chttp2/transport/incoming_metadata.h
@@ -42,6 +42,7 @@ typedef struct {
   size_t capacity;
   gpr_timespec deadline;
   int published;
+  size_t size;  // total size of metadata
 } grpc_chttp2_incoming_metadata_buffer;
 
 /** assumes everything initially zeroed */
diff --git a/src/core/ext/transport/chttp2/transport/internal.h b/src/core/ext/transport/chttp2/transport/internal.h
index 8c4fa2d34a..5872fd8e0a 100644
--- a/src/core/ext/transport/chttp2/transport/internal.h
+++ b/src/core/ext/transport/chttp2/transport/internal.h
@@ -422,23 +422,21 @@ typedef struct {
   /** number of streams that are currently being read */
   gpr_refcount active_streams;
 
-  /** when the application requests writes be closed, the write_closed is
-      'queued'; when the close is flow controlled into the send path, we are
-      'sending' it; when the write has been performed it is 'sent' */
+  /** Is this stream closed for writing. */
   bool write_closed;
-  /** is this stream reading half-closed (boolean) */
+  /** Is this stream reading half-closed. */
   bool read_closed;
-  /** are all published incoming byte streams closed */
+  /** Are all published incoming byte streams closed. */
   bool all_incoming_byte_streams_finished;
-  /** is this stream in the stream map? (boolean) */
+  /** Is this stream in the stream map. */
   bool in_stream_map;
-  /** has this stream seen an error? if 1, then pending incoming frames
-      can be thrown away */
+  /** Has this stream seen an error.
+      If true, then pending incoming frames can be thrown away. */
   bool seen_error;
+  bool exceeded_metadata_size;
 
   bool published_initial_metadata;
   bool published_trailing_metadata;
-  bool faked_trailing_metadata;
 
   grpc_chttp2_incoming_metadata_buffer received_initial_metadata;
   grpc_chttp2_incoming_metadata_buffer received_trailing_metadata;
@@ -481,7 +479,8 @@ struct grpc_chttp2_stream_parsing {
   /** which metadata did we get (on this parse) */
   uint8_t got_metadata_on_parse[2];
   /** should we raise the seen_error flag in transport_global */
-  uint8_t seen_error;
+  bool seen_error;
+  bool exceeded_metadata_size;
   /** window available for peer to send to us */
   int64_t incoming_window;
   /** parsing state for data frames */
diff --git a/src/core/ext/transport/chttp2/transport/parsing.c b/src/core/ext/transport/chttp2/transport/parsing.c
index 2995066e51..4bd374b7fa 100644
--- a/src/core/ext/transport/chttp2/transport/parsing.c
+++ b/src/core/ext/transport/chttp2/transport/parsing.c
@@ -45,6 +45,10 @@
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/transport/static_metadata.h"
 
+#define TRANSPORT_FROM_PARSING(tp)                                        \
+  ((grpc_chttp2_transport *)((char *)(tp)-offsetof(grpc_chttp2_transport, \
+                                                   parsing)))
+
 static int init_frame_parser(grpc_exec_ctx *exec_ctx,
                              grpc_chttp2_transport_parsing *transport_parsing);
 static int init_header_frame_parser(
@@ -170,7 +174,9 @@ void grpc_chttp2_publish_reads(
   while (grpc_chttp2_list_pop_parsing_seen_stream(
       transport_global, transport_parsing, &stream_global, &stream_parsing)) {
     if (stream_parsing->seen_error) {
-      stream_global->seen_error = 1;
+      stream_global->seen_error = true;
+      stream_global->exceeded_metadata_size =
+          stream_parsing->exceeded_metadata_size;
       grpc_chttp2_list_add_check_read_ops(transport_global, stream_global);
     }
 
@@ -612,7 +618,7 @@ static void on_initial_header(void *tp, grpc_mdelem *md) {
 
   if (md->key == GRPC_MDSTR_GRPC_STATUS && md != GRPC_MDELEM_GRPC_STATUS_0) {
     /* TODO(ctiller): check for a status like " 0" */
-    stream_parsing->seen_error = 1;
+    stream_parsing->seen_error = true;
   }
 
   if (md->key == GRPC_MDSTR_GRPC_TIMEOUT) {
@@ -633,8 +639,26 @@ static void on_initial_header(void *tp, grpc_mdelem *md) {
         gpr_time_add(gpr_now(GPR_CLOCK_MONOTONIC), *cached_timeout));
     GRPC_MDELEM_UNREF(md);
   } else {
-    grpc_chttp2_incoming_metadata_buffer_add(
-        &stream_parsing->metadata_buffer[0], md);
+    const size_t new_size =
+        stream_parsing->metadata_buffer[0].size + GRPC_MDELEM_LENGTH(md);
+    grpc_chttp2_transport_global *transport_global =
+        &TRANSPORT_FROM_PARSING(transport_parsing)->global;
+    const size_t metadata_size_limit =
+        transport_global->settings[GRPC_LOCAL_SETTINGS]
+                                  [GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE];
+    if (new_size > metadata_size_limit) {
+      if (!stream_parsing->exceeded_metadata_size) {
+        gpr_log(GPR_DEBUG,
+                "received initial metadata size exceeds limit (%lu vs. %lu)",
+                new_size, metadata_size_limit);
+        stream_parsing->seen_error = true;
+        stream_parsing->exceeded_metadata_size = true;
+      }
+      GRPC_MDELEM_UNREF(md);
+    } else {
+      grpc_chttp2_incoming_metadata_buffer_add(
+          &stream_parsing->metadata_buffer[0], md);
+    }
   }
 
   grpc_chttp2_list_add_parsing_seen_stream(transport_parsing, stream_parsing);
@@ -658,12 +682,30 @@ static void on_trailing_header(void *tp, grpc_mdelem *md) {
 
   if (md->key == GRPC_MDSTR_GRPC_STATUS && md != GRPC_MDELEM_GRPC_STATUS_0) {
     /* TODO(ctiller): check for a status like " 0" */
-    stream_parsing->seen_error = 1;
+    stream_parsing->seen_error = true;
+  }
+
+  const size_t new_size =
+      stream_parsing->metadata_buffer[1].size + GRPC_MDELEM_LENGTH(md);
+  grpc_chttp2_transport_global *transport_global =
+      &TRANSPORT_FROM_PARSING(transport_parsing)->global;
+  const size_t metadata_size_limit =
+      transport_global->settings[GRPC_LOCAL_SETTINGS]
+                                [GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE];
+  if (new_size > metadata_size_limit) {
+    if (!stream_parsing->exceeded_metadata_size) {
+      gpr_log(GPR_DEBUG,
+              "received trailing metadata size exceeds limit (%lu vs. %lu)",
+              new_size, metadata_size_limit);
+      stream_parsing->seen_error = true;
+      stream_parsing->exceeded_metadata_size = true;
+    }
+    GRPC_MDELEM_UNREF(md);
+  } else {
+    grpc_chttp2_incoming_metadata_buffer_add(
+        &stream_parsing->metadata_buffer[1], md);
   }
 
-  grpc_chttp2_incoming_metadata_buffer_add(&stream_parsing->metadata_buffer[1],
-                                           md);
-
   grpc_chttp2_list_add_parsing_seen_stream(transport_parsing, stream_parsing);
 
   GPR_TIMER_END("on_trailing_header", 0);
diff --git a/src/core/lib/channel/channel_args.h b/src/core/lib/channel/channel_args.h
index 0a51780a14..23c7b7b897 100644
--- a/src/core/lib/channel/channel_args.h
+++ b/src/core/lib/channel/channel_args.h
@@ -56,10 +56,6 @@ grpc_channel_args *grpc_channel_args_merge(const grpc_channel_args *a,
 /** Destroy arguments created by \a grpc_channel_args_copy */
 void grpc_channel_args_destroy(grpc_channel_args *a);
 
-/** Reads census_enabled settings from channel args. Returns 1 if census_enabled
- * is specified in channel args, otherwise returns 0. */
-int grpc_channel_args_is_census_enabled(const grpc_channel_args *a);
-
 /** Returns the compression algorithm set in \a a. */
 grpc_compression_algorithm grpc_channel_args_get_compression_algorithm(
     const grpc_channel_args *a);
diff --git a/src/core/lib/iomgr/tcp_posix.c b/src/core/lib/iomgr/tcp_posix.c
index 7210aef5d5..e2869224f1 100644
--- a/src/core/lib/iomgr/tcp_posix.c
+++ b/src/core/lib/iomgr/tcp_posix.c
@@ -164,7 +164,7 @@ static void call_read_cb(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp, int success) {
     for (i = 0; i < tcp->incoming_buffer->count; i++) {
       char *dump = gpr_dump_slice(tcp->incoming_buffer->slices[i],
                                   GPR_DUMP_HEX | GPR_DUMP_ASCII);
-      gpr_log(GPR_DEBUG, "READ %p: %s", tcp, dump);
+      gpr_log(GPR_DEBUG, "READ %p (peer=%s): %s", tcp, tcp->peer_string, dump);
       gpr_free(dump);
     }
   }
@@ -398,7 +398,7 @@ static void tcp_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
     for (i = 0; i < buf->count; i++) {
       char *data =
           gpr_dump_slice(buf->slices[i], GPR_DUMP_HEX | GPR_DUMP_ASCII);
-      gpr_log(GPR_DEBUG, "WRITE %p: %s", tcp, data);
+      gpr_log(GPR_DEBUG, "WRITE %p (peer=%s): %s", tcp, tcp->peer_string, data);
       gpr_free(data);
     }
   }
diff --git a/src/core/lib/security/credentials/composite/composite_credentials.c b/src/core/lib/security/credentials/composite/composite_credentials.c
index 4a17f7c1b9..18189a8fb8 100644
--- a/src/core/lib/security/credentials/composite/composite_credentials.c
+++ b/src/core/lib/security/credentials/composite/composite_credentials.c
@@ -260,4 +260,3 @@ grpc_channel_credentials *grpc_composite_channel_credentials_create(
   c->call_creds = grpc_call_credentials_ref(call_creds);
   return &c->base;
 }
-
diff --git a/src/core/lib/security/credentials/composite/composite_credentials.h b/src/core/lib/security/credentials/composite/composite_credentials.h
index 96d3b14cc4..0d8966f464 100644
--- a/src/core/lib/security/credentials/composite/composite_credentials.h
+++ b/src/core/lib/security/credentials/composite/composite_credentials.h
@@ -68,5 +68,5 @@ typedef struct {
   grpc_call_credentials_array inner;
 } grpc_composite_call_credentials;
 
-#endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_COMPOSITE_COMPOSITE_CREDENTIALS_H */
-
+#endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_COMPOSITE_COMPOSITE_CREDENTIALS_H \
+          */
diff --git a/src/core/lib/security/credentials/credentials.c b/src/core/lib/security/credentials/credentials.c
index 29cf9ee884..3dde6e587d 100644
--- a/src/core/lib/security/credentials/credentials.c
+++ b/src/core/lib/security/credentials/credentials.c
@@ -53,10 +53,9 @@
 
 /* -- Common. -- */
 
-grpc_credentials_metadata_request *
-grpc_credentials_metadata_request_create(grpc_call_credentials *creds,
-                                         grpc_credentials_metadata_cb cb,
-                                         void *user_data) {
+grpc_credentials_metadata_request *grpc_credentials_metadata_request_create(
+    grpc_call_credentials *creds, grpc_credentials_metadata_cb cb,
+    void *user_data) {
   grpc_credentials_metadata_request *r =
       gpr_malloc(sizeof(grpc_credentials_metadata_request));
   r->creds = grpc_call_credentials_ref(creds);
@@ -230,4 +229,3 @@ grpc_server_credentials *grpc_find_server_credentials_in_args(
   }
   return NULL;
 }
-
diff --git a/src/core/lib/security/credentials/fake/fake_credentials.c b/src/core/lib/security/credentials/fake/fake_credentials.c
index 2a5d225078..54d7cf2581 100644
--- a/src/core/lib/security/credentials/fake/fake_credentials.c
+++ b/src/core/lib/security/credentials/fake/fake_credentials.c
@@ -136,4 +136,3 @@ grpc_call_credentials *grpc_md_only_test_credentials_create(
   c->is_async = is_async;
   return &c->base;
 }
-
diff --git a/src/core/lib/security/credentials/google_default/google_default_credentials.c b/src/core/lib/security/credentials/google_default/google_default_credentials.c
index da23bba62b..a521d95abc 100644
--- a/src/core/lib/security/credentials/google_default/google_default_credentials.c
+++ b/src/core/lib/security/credentials/google_default/google_default_credentials.c
@@ -41,8 +41,8 @@
 
 #include "src/core/lib/http/httpcli.h"
 #include "src/core/lib/http/parser.h"
-#include "src/core/lib/security/credentials/oauth2/oauth2_credentials.h"
 #include "src/core/lib/security/credentials/jwt/jwt_credentials.h"
+#include "src/core/lib/security/credentials/oauth2/oauth2_credentials.h"
 #include "src/core/lib/support/env.h"
 #include "src/core/lib/support/load_file.h"
 #include "src/core/lib/surface/api_trace.h"
diff --git a/src/core/lib/security/credentials/google_default/google_default_credentials.h b/src/core/lib/security/credentials/google_default/google_default_credentials.h
index fa3f1ae1bf..fac4377e2c 100644
--- a/src/core/lib/security/credentials/google_default/google_default_credentials.h
+++ b/src/core/lib/security/credentials/google_default/google_default_credentials.h
@@ -42,5 +42,5 @@
 
 void grpc_flush_cached_google_default_credentials(void);
 
-#endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_GOOGLE_DEFAULT_GOOGLE_DEFAULT_CREDENTIALS_H */
-
+#endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_GOOGLE_DEFAULT_GOOGLE_DEFAULT_CREDENTIALS_H \
+          */
diff --git a/src/core/lib/security/credentials/iam/iam_credentials.c b/src/core/lib/security/credentials/iam/iam_credentials.c
index ec0f2841f2..89defa7c60 100644
--- a/src/core/lib/security/credentials/iam/iam_credentials.c
+++ b/src/core/lib/security/credentials/iam/iam_credentials.c
@@ -83,5 +83,3 @@ grpc_call_credentials *grpc_google_iam_credentials_create(
       c->iam_md, GRPC_IAM_AUTHORITY_SELECTOR_METADATA_KEY, authority_selector);
   return &c->base;
 }
-
-
diff --git a/src/core/lib/security/credentials/iam/iam_credentials.h b/src/core/lib/security/credentials/iam/iam_credentials.h
index 58b77723fd..af54faa586 100644
--- a/src/core/lib/security/credentials/iam/iam_credentials.h
+++ b/src/core/lib/security/credentials/iam/iam_credentials.h
@@ -42,4 +42,3 @@ typedef struct {
 } grpc_google_iam_credentials;
 
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_IAM_IAM_CREDENTIALS_H */
-
diff --git a/src/core/lib/security/credentials/jwt/json_token.c b/src/core/lib/security/credentials/jwt/json_token.c
index fd3d0d6a64..354c13133e 100644
--- a/src/core/lib/security/credentials/jwt/json_token.c
+++ b/src/core/lib/security/credentials/jwt/json_token.c
@@ -318,4 +318,3 @@ void grpc_jwt_encode_and_sign_set_override(
     grpc_jwt_encode_and_sign_override func) {
   g_jwt_encode_and_sign_override = func;
 }
-
diff --git a/src/core/lib/security/credentials/jwt/jwt_credentials.c b/src/core/lib/security/credentials/jwt/jwt_credentials.c
index 9fd0527a52..8755a96af4 100644
--- a/src/core/lib/security/credentials/jwt/jwt_credentials.c
+++ b/src/core/lib/security/credentials/jwt/jwt_credentials.c
@@ -158,4 +158,3 @@ grpc_call_credentials *grpc_service_account_jwt_access_credentials_create(
   return grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
       grpc_auth_json_key_create_from_string(json_key), token_lifetime);
 }
-
diff --git a/src/core/lib/security/credentials/jwt/jwt_credentials.h b/src/core/lib/security/credentials/jwt/jwt_credentials.h
index acc73dd47f..d572606179 100644
--- a/src/core/lib/security/credentials/jwt/jwt_credentials.h
+++ b/src/core/lib/security/credentials/jwt/jwt_credentials.h
@@ -60,4 +60,3 @@ grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
     grpc_auth_json_key key, gpr_timespec token_lifetime);
 
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_JWT_JWT_CREDENTIALS_H */
-
diff --git a/src/core/lib/security/credentials/oauth2/oauth2_credentials.c b/src/core/lib/security/credentials/oauth2/oauth2_credentials.c
index 0984d1f53f..973c6e1d17 100644
--- a/src/core/lib/security/credentials/oauth2/oauth2_credentials.c
+++ b/src/core/lib/security/credentials/oauth2/oauth2_credentials.c
@@ -426,5 +426,3 @@ grpc_call_credentials *grpc_access_token_credentials_create(
   gpr_free(token_md_value);
   return &c->base;
 }
-
-
diff --git a/src/core/lib/security/credentials/oauth2/oauth2_credentials.h b/src/core/lib/security/credentials/oauth2/oauth2_credentials.h
index 4d28fce629..04915b333f 100644
--- a/src/core/lib/security/credentials/oauth2/oauth2_credentials.h
+++ b/src/core/lib/security/credentials/oauth2/oauth2_credentials.h
@@ -82,7 +82,6 @@ typedef struct {
   grpc_fetch_oauth2_func fetch_func;
 } grpc_oauth2_token_fetcher_credentials;
 
-
 // Google refresh token credentials.
 typedef struct {
   grpc_oauth2_token_fetcher_credentials base;
@@ -108,4 +107,3 @@ grpc_oauth2_token_fetcher_credentials_parse_server_response(
     grpc_credentials_md_store **token_md, gpr_timespec *token_lifetime);
 
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_OAUTH2_OAUTH2_CREDENTIALS_H */
-
diff --git a/src/core/lib/security/credentials/plugin/plugin_credentials.c b/src/core/lib/security/credentials/plugin/plugin_credentials.c
index b075e14551..bae357321e 100644
--- a/src/core/lib/security/credentials/plugin/plugin_credentials.c
+++ b/src/core/lib/security/credentials/plugin/plugin_credentials.c
@@ -127,5 +127,3 @@ grpc_call_credentials *grpc_metadata_credentials_create_from_plugin(
   c->plugin = plugin;
   return &c->base;
 }
-
-
diff --git a/src/core/lib/security/credentials/plugin/plugin_credentials.h b/src/core/lib/security/credentials/plugin/plugin_credentials.h
index 5b28531152..89073cb3d1 100644
--- a/src/core/lib/security/credentials/plugin/plugin_credentials.h
+++ b/src/core/lib/security/credentials/plugin/plugin_credentials.h
@@ -43,4 +43,3 @@ typedef struct {
 } grpc_plugin_credentials;
 
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_PLUGIN_PLUGIN_CREDENTIALS_H */
-
diff --git a/src/core/lib/security/credentials/ssl/ssl_credentials.c b/src/core/lib/security/credentials/ssl/ssl_credentials.c
index ee8d2e4365..545bca9d98 100644
--- a/src/core/lib/security/credentials/ssl/ssl_credentials.c
+++ b/src/core/lib/security/credentials/ssl/ssl_credentials.c
@@ -160,7 +160,6 @@ static void ssl_server_destruct(grpc_server_credentials *creds) {
   if (c->config.pem_root_certs != NULL) gpr_free(c->config.pem_root_certs);
 }
 
-
 static grpc_security_status ssl_server_create_security_connector(
     grpc_server_credentials *creds, grpc_server_security_connector **sc) {
   grpc_ssl_server_credentials *c = (grpc_ssl_server_credentials *)creds;
@@ -170,7 +169,6 @@ static grpc_security_status ssl_server_create_security_connector(
 static grpc_server_credentials_vtable ssl_server_vtable = {
     ssl_server_destruct, ssl_server_create_security_connector};
 
-
 static void ssl_build_server_config(
     const char *pem_root_certs, grpc_ssl_pem_key_cert_pair *pem_key_cert_pairs,
     size_t num_key_cert_pairs,
@@ -206,7 +204,6 @@ static void ssl_build_server_config(
   }
 }
 
-
 grpc_server_credentials *grpc_ssl_server_credentials_create(
     const char *pem_root_certs, grpc_ssl_pem_key_cert_pair *pem_key_cert_pairs,
     size_t num_key_cert_pairs, int force_client_auth, void *reserved) {
@@ -241,4 +238,3 @@ grpc_server_credentials *grpc_ssl_server_credentials_create_ex(
                           &c->config);
   return &c->base;
 }
-
diff --git a/src/core/lib/security/credentials/ssl/ssl_credentials.h b/src/core/lib/security/credentials/ssl/ssl_credentials.h
index ea4bdabc04..f23dbdbe49 100644
--- a/src/core/lib/security/credentials/ssl/ssl_credentials.h
+++ b/src/core/lib/security/credentials/ssl/ssl_credentials.h
@@ -46,4 +46,3 @@ typedef struct {
 } grpc_ssl_server_credentials;
 
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_SSL_SSL_CREDENTIALS_H */
-
diff --git a/src/core/lib/security/util/json_util.c b/src/core/lib/security/util/json_util.c
index 9eda12c628..7eed039baa 100644
--- a/src/core/lib/security/util/json_util.c
+++ b/src/core/lib/security/util/json_util.c
@@ -59,4 +59,3 @@ bool grpc_copy_json_string_property(const grpc_json *json,
   *copied_value = gpr_strdup(prop_value);
   return true;
 }
-
diff --git a/src/core/lib/security/util/json_util.h b/src/core/lib/security/util/json_util.h
index 7f3d4659c3..137900593f 100644
--- a/src/core/lib/security/util/json_util.h
+++ b/src/core/lib/security/util/json_util.h
@@ -50,8 +50,6 @@ const char *grpc_json_get_string_property(const grpc_json *json,
 // Copies the value of the json child property specified by prop_name.
 // Returns false if the property was not found.
 bool grpc_copy_json_string_property(const grpc_json *json,
-                                    const char *prop_name,
-                                    char **copied_value);
+                                    const char *prop_name, char **copied_value);
 
 #endif /* GRPC_CORE_LIB_SECURITY_UTIL_JSON_UTIL_H */
-
diff --git a/src/core/lib/surface/version.c b/src/core/lib/surface/version.c
index fe954cbefb..aca76d2bb7 100644
--- a/src/core/lib/surface/version.c
+++ b/src/core/lib/surface/version.c
@@ -36,4 +36,4 @@
 
 #include <grpc/grpc.h>
 
-const char *grpc_version_string(void) { return "0.14.0-dev"; }
+const char *grpc_version_string(void) { return "0.15.0-dev"; }
diff --git a/src/core/lib/transport/metadata.h b/src/core/lib/transport/metadata.h
index 713d9e6782..6d82f4d681 100644
--- a/src/core/lib/transport/metadata.h
+++ b/src/core/lib/transport/metadata.h
@@ -147,6 +147,10 @@ const char *grpc_mdstr_as_c_string(grpc_mdstr *s);
 
 #define GRPC_MDSTR_LENGTH(s) (GPR_SLICE_LENGTH(s->slice))
 
+/* We add 32 bytes of padding as per RFC-7540 section 6.5.2. */
+#define GRPC_MDELEM_LENGTH(e) \
+  (GRPC_MDSTR_LENGTH((e)->key) + GRPC_MDSTR_LENGTH((e)->value) + 32)
+
 int grpc_mdstr_is_legal_header(grpc_mdstr *s);
 int grpc_mdstr_is_legal_nonbin_header(grpc_mdstr *s);
 int grpc_mdstr_is_bin_suffixed(grpc_mdstr *s);
diff --git a/src/core/lib/transport/metadata_batch.c b/src/core/lib/transport/metadata_batch.c
index 4567221a48..e4398abeb7 100644
--- a/src/core/lib/transport/metadata_batch.c
+++ b/src/core/lib/transport/metadata_batch.c
@@ -192,3 +192,12 @@ int grpc_metadata_batch_is_empty(grpc_metadata_batch *batch) {
          gpr_time_cmp(gpr_inf_future(batch->deadline.clock_type),
                       batch->deadline) == 0;
 }
+
+size_t grpc_metadata_batch_size(grpc_metadata_batch *batch) {
+  size_t size = 0;
+  for (grpc_linked_mdelem *elem = batch->list.head; elem != NULL;
+       elem = elem->next) {
+    size += GRPC_MDELEM_LENGTH(elem->md);
+  }
+  return size;
+}
diff --git a/src/core/lib/transport/metadata_batch.h b/src/core/lib/transport/metadata_batch.h
index b62668876e..7af823f7ca 100644
--- a/src/core/lib/transport/metadata_batch.h
+++ b/src/core/lib/transport/metadata_batch.h
@@ -66,6 +66,9 @@ void grpc_metadata_batch_destroy(grpc_metadata_batch *batch);
 void grpc_metadata_batch_clear(grpc_metadata_batch *batch);
 int grpc_metadata_batch_is_empty(grpc_metadata_batch *batch);
 
+/* Returns the transport size of the batch. */
+size_t grpc_metadata_batch_size(grpc_metadata_batch *batch);
+
 /** Moves the metadata information from \a src to \a dst. Upon return, \a src is
  * zeroed. */
 void grpc_metadata_batch_move(grpc_metadata_batch *dst,
diff --git a/src/cpp/common/core_codegen.cc b/src/cpp/common/core_codegen.cc
index 33a8f755e6..8e8d42eb29 100644
--- a/src/cpp/common/core_codegen.cc
+++ b/src/cpp/common/core_codegen.cc
@@ -48,124 +48,6 @@
 
 #include "src/core/lib/profiling/timers.h"
 
-namespace {
-
-const int kGrpcBufferWriterMaxBufferLength = 8192;
-
-class GrpcBufferWriter GRPC_FINAL
-    : public ::grpc::protobuf::io::ZeroCopyOutputStream {
- public:
-  explicit GrpcBufferWriter(grpc_byte_buffer** bp, int block_size)
-      : block_size_(block_size), byte_count_(0), have_backup_(false) {
-    *bp = grpc_raw_byte_buffer_create(NULL, 0);
-    slice_buffer_ = &(*bp)->data.raw.slice_buffer;
-  }
-
-  ~GrpcBufferWriter() GRPC_OVERRIDE {
-    if (have_backup_) {
-      gpr_slice_unref(backup_slice_);
-    }
-  }
-
-  bool Next(void** data, int* size) GRPC_OVERRIDE {
-    if (have_backup_) {
-      slice_ = backup_slice_;
-      have_backup_ = false;
-    } else {
-      slice_ = gpr_slice_malloc(block_size_);
-    }
-    *data = GPR_SLICE_START_PTR(slice_);
-    // On win x64, int is only 32bit
-    GPR_ASSERT(GPR_SLICE_LENGTH(slice_) <= INT_MAX);
-    byte_count_ += * size = (int)GPR_SLICE_LENGTH(slice_);
-    gpr_slice_buffer_add(slice_buffer_, slice_);
-    return true;
-  }
-
-  void BackUp(int count) GRPC_OVERRIDE {
-    gpr_slice_buffer_pop(slice_buffer_);
-    if (count == block_size_) {
-      backup_slice_ = slice_;
-    } else {
-      backup_slice_ =
-          gpr_slice_split_tail(&slice_, GPR_SLICE_LENGTH(slice_) - count);
-      gpr_slice_buffer_add(slice_buffer_, slice_);
-    }
-    have_backup_ = true;
-    byte_count_ -= count;
-  }
-
-  grpc::protobuf::int64 ByteCount() const GRPC_OVERRIDE { return byte_count_; }
-
- private:
-  const int block_size_;
-  int64_t byte_count_;
-  gpr_slice_buffer* slice_buffer_;
-  bool have_backup_;
-  gpr_slice backup_slice_;
-  gpr_slice slice_;
-};
-
-class GrpcBufferReader GRPC_FINAL
-    : public ::grpc::protobuf::io::ZeroCopyInputStream {
- public:
-  explicit GrpcBufferReader(grpc_byte_buffer* buffer)
-      : byte_count_(0), backup_count_(0) {
-    grpc_byte_buffer_reader_init(&reader_, buffer);
-  }
-  ~GrpcBufferReader() GRPC_OVERRIDE {
-    grpc_byte_buffer_reader_destroy(&reader_);
-  }
-
-  bool Next(const void** data, int* size) GRPC_OVERRIDE {
-    if (backup_count_ > 0) {
-      *data = GPR_SLICE_START_PTR(slice_) + GPR_SLICE_LENGTH(slice_) -
-              backup_count_;
-      GPR_ASSERT(backup_count_ <= INT_MAX);
-      *size = (int)backup_count_;
-      backup_count_ = 0;
-      return true;
-    }
-    if (!grpc_byte_buffer_reader_next(&reader_, &slice_)) {
-      return false;
-    }
-    gpr_slice_unref(slice_);
-    *data = GPR_SLICE_START_PTR(slice_);
-    // On win x64, int is only 32bit
-    GPR_ASSERT(GPR_SLICE_LENGTH(slice_) <= INT_MAX);
-    byte_count_ += * size = (int)GPR_SLICE_LENGTH(slice_);
-    return true;
-  }
-
-  void BackUp(int count) GRPC_OVERRIDE { backup_count_ = count; }
-
-  bool Skip(int count) GRPC_OVERRIDE {
-    const void* data;
-    int size;
-    while (Next(&data, &size)) {
-      if (size >= count) {
-        BackUp(size - count);
-        return true;
-      }
-      // size < count;
-      count -= size;
-    }
-    // error or we have too large count;
-    return false;
-  }
-
-  grpc::protobuf::int64 ByteCount() const GRPC_OVERRIDE {
-    return byte_count_ - backup_count_;
-  }
-
- private:
-  int64_t byte_count_;
-  int64_t backup_count_;
-  grpc_byte_buffer_reader reader_;
-  gpr_slice slice_;
-};
-}  // namespace
-
 namespace grpc {
 
 grpc_completion_queue* CoreCodegen::grpc_completion_queue_create(
@@ -192,6 +74,44 @@ void CoreCodegen::grpc_byte_buffer_destroy(grpc_byte_buffer* bb) {
   ::grpc_byte_buffer_destroy(bb);
 }
 
+void CoreCodegen::grpc_byte_buffer_reader_init(grpc_byte_buffer_reader* reader,
+                                               grpc_byte_buffer* buffer) {
+  ::grpc_byte_buffer_reader_init(reader, buffer);
+}
+
+void CoreCodegen::grpc_byte_buffer_reader_destroy(
+    grpc_byte_buffer_reader* reader) {
+  ::grpc_byte_buffer_reader_destroy(reader);
+}
+
+int CoreCodegen::grpc_byte_buffer_reader_next(grpc_byte_buffer_reader* reader,
+                                              gpr_slice* slice) {
+  return ::grpc_byte_buffer_reader_next(reader, slice);
+}
+
+grpc_byte_buffer* CoreCodegen::grpc_raw_byte_buffer_create(gpr_slice* slice,
+                                                           size_t nslices) {
+  return ::grpc_raw_byte_buffer_create(slice, nslices);
+}
+
+gpr_slice CoreCodegen::gpr_slice_malloc(size_t length) {
+  return ::gpr_slice_malloc(length);
+}
+
+void CoreCodegen::gpr_slice_unref(gpr_slice slice) { ::gpr_slice_unref(slice); }
+
+gpr_slice CoreCodegen::gpr_slice_split_tail(gpr_slice* s, size_t split) {
+  return ::gpr_slice_split_tail(s, split);
+}
+
+void CoreCodegen::gpr_slice_buffer_add(gpr_slice_buffer* sb, gpr_slice slice) {
+  ::gpr_slice_buffer_add(sb, slice);
+}
+
+void CoreCodegen::gpr_slice_buffer_pop(gpr_slice_buffer* sb) {
+  ::gpr_slice_buffer_pop(sb);
+}
+
 void CoreCodegen::grpc_metadata_array_init(grpc_metadata_array* array) {
   ::grpc_metadata_array_init(array);
 }
@@ -200,6 +120,10 @@ void CoreCodegen::grpc_metadata_array_destroy(grpc_metadata_array* array) {
   ::grpc_metadata_array_destroy(array);
 }
 
+const Status& CoreCodegen::ok() { return grpc::Status::OK; }
+
+const Status& CoreCodegen::cancelled() { return grpc::Status::CANCELLED; }
+
 gpr_timespec CoreCodegen::gpr_inf_future(gpr_clock_type type) {
   return ::gpr_inf_future(type);
 }
@@ -209,48 +133,4 @@ void CoreCodegen::assert_fail(const char* failed_assertion) {
   abort();
 }
 
-Status CoreCodegen::SerializeProto(const grpc::protobuf::Message& msg,
-                                   grpc_byte_buffer** bp) {
-  GPR_TIMER_SCOPE("SerializeProto", 0);
-  int byte_size = msg.ByteSize();
-  if (byte_size <= kGrpcBufferWriterMaxBufferLength) {
-    gpr_slice slice = gpr_slice_malloc(byte_size);
-    GPR_ASSERT(GPR_SLICE_END_PTR(slice) ==
-               msg.SerializeWithCachedSizesToArray(GPR_SLICE_START_PTR(slice)));
-    *bp = grpc_raw_byte_buffer_create(&slice, 1);
-    gpr_slice_unref(slice);
-    return Status::OK;
-  } else {
-    GrpcBufferWriter writer(bp, kGrpcBufferWriterMaxBufferLength);
-    return msg.SerializeToZeroCopyStream(&writer)
-               ? Status::OK
-               : Status(StatusCode::INTERNAL, "Failed to serialize message");
-  }
-}
-
-Status CoreCodegen::DeserializeProto(grpc_byte_buffer* buffer,
-                                     grpc::protobuf::Message* msg,
-                                     int max_message_size) {
-  GPR_TIMER_SCOPE("DeserializeProto", 0);
-  if (buffer == nullptr) {
-    return Status(StatusCode::INTERNAL, "No payload");
-  }
-  Status result = Status::OK;
-  {
-    GrpcBufferReader reader(buffer);
-    ::grpc::protobuf::io::CodedInputStream decoder(&reader);
-    if (max_message_size > 0) {
-      decoder.SetTotalBytesLimit(max_message_size, max_message_size);
-    }
-    if (!msg->ParseFromCodedStream(&decoder)) {
-      result = Status(StatusCode::INTERNAL, msg->InitializationErrorString());
-    }
-    if (!decoder.ConsumedEntireMessage()) {
-      result = Status(StatusCode::INTERNAL, "Did not read entire message");
-    }
-  }
-  grpc_byte_buffer_destroy(buffer);
-  return result;
-}
-
 }  // namespace grpc
diff --git a/src/cpp/common/core_codegen.h b/src/cpp/common/core_codegen.h
index e15cb4c34a..656b11e7e7 100644
--- a/src/cpp/common/core_codegen.h
+++ b/src/cpp/common/core_codegen.h
@@ -42,13 +42,6 @@ namespace grpc {
 /// Implementation of the core codegen interface.
 class CoreCodegen : public CoreCodegenInterface {
  private:
-  Status SerializeProto(const grpc::protobuf::Message& msg,
-                        grpc_byte_buffer** bp) override;
-
-  Status DeserializeProto(grpc_byte_buffer* buffer,
-                          grpc::protobuf::Message* msg,
-                          int max_message_size) override;
-
   grpc_completion_queue* grpc_completion_queue_create(void* reserved) override;
   void grpc_completion_queue_destroy(grpc_completion_queue* cq) override;
   grpc_event grpc_completion_queue_pluck(grpc_completion_queue* cq, void* tag,
@@ -60,11 +53,30 @@ class CoreCodegen : public CoreCodegenInterface {
 
   void grpc_byte_buffer_destroy(grpc_byte_buffer* bb) override;
 
+  void grpc_byte_buffer_reader_init(grpc_byte_buffer_reader* reader,
+                                    grpc_byte_buffer* buffer) override;
+  void grpc_byte_buffer_reader_destroy(
+      grpc_byte_buffer_reader* reader) override;
+  int grpc_byte_buffer_reader_next(grpc_byte_buffer_reader* reader,
+                                   gpr_slice* slice) override;
+
+  grpc_byte_buffer* grpc_raw_byte_buffer_create(gpr_slice* slice,
+                                                size_t nslices) override;
+
+  gpr_slice gpr_slice_malloc(size_t length) override;
+  void gpr_slice_unref(gpr_slice slice) override;
+  gpr_slice gpr_slice_split_tail(gpr_slice* s, size_t split) override;
+  void gpr_slice_buffer_add(gpr_slice_buffer* sb, gpr_slice slice) override;
+  void gpr_slice_buffer_pop(gpr_slice_buffer* sb) override;
+
   void grpc_metadata_array_init(grpc_metadata_array* array) override;
   void grpc_metadata_array_destroy(grpc_metadata_array* array) override;
 
   gpr_timespec gpr_inf_future(gpr_clock_type type) override;
 
+  virtual const Status& ok() override;
+  virtual const Status& cancelled() override;
+
   void assert_fail(const char* failed_assertion) override;
 };
 
diff --git a/src/csharp/Grpc.Core.Tests/Internal/AsyncCallServerTest.cs b/src/csharp/Grpc.Core.Tests/Internal/AsyncCallServerTest.cs
index 058371521d..0e204761f6 100644
--- a/src/csharp/Grpc.Core.Tests/Internal/AsyncCallServerTest.cs
+++ b/src/csharp/Grpc.Core.Tests/Internal/AsyncCallServerTest.cs
@@ -168,7 +168,7 @@ namespace Grpc.Core.Internal.Tests
             var responseStream = new ServerResponseStream<string, string>(asyncCallServer);
 
             var writeTask = responseStream.WriteAsync("request1");
-            var writeStatusTask = asyncCallServer.SendStatusFromServerAsync(Status.DefaultSuccess, new Metadata());
+            var writeStatusTask = asyncCallServer.SendStatusFromServerAsync(Status.DefaultSuccess, new Metadata(), null);
 
             fakeCall.SendCompletionHandler(true);
             fakeCall.SendStatusFromServerHandler(true);
diff --git a/src/csharp/Grpc.Core.Tests/Internal/FakeNativeCall.cs b/src/csharp/Grpc.Core.Tests/Internal/FakeNativeCall.cs
index 1bec258ca2..909112a47c 100644
--- a/src/csharp/Grpc.Core.Tests/Internal/FakeNativeCall.cs
+++ b/src/csharp/Grpc.Core.Tests/Internal/FakeNativeCall.cs
@@ -165,7 +165,8 @@ namespace Grpc.Core.Internal.Tests
             SendCompletionHandler = callback;
         }
 
-        public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
+        public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata,
+            byte[] optionalPayload, WriteFlags writeFlags)
         {
             SendStatusFromServerHandler = callback;
         }
diff --git a/src/csharp/Grpc.Core/GrpcEnvironment.cs b/src/csharp/Grpc.Core/GrpcEnvironment.cs
index a5c78cc9d7..bee0ef1d62 100644
--- a/src/csharp/Grpc.Core/GrpcEnvironment.cs
+++ b/src/csharp/Grpc.Core/GrpcEnvironment.cs
@@ -45,11 +45,12 @@ namespace Grpc.Core
     /// </summary>
     public class GrpcEnvironment
     {
-        const int THREAD_POOL_SIZE = 4;
+        const int MinDefaultThreadPoolSize = 4;
 
         static object staticLock = new object();
         static GrpcEnvironment instance;
         static int refCount;
+        static int? customThreadPoolSize;
 
         static ILogger logger = new ConsoleLogger();
 
@@ -123,13 +124,30 @@ namespace Grpc.Core
         }
 
         /// <summary>
+        /// Sets the number of threads in the gRPC thread pool that polls for internal RPC events.
+        /// Can be only invoke before the <c>GrpcEnviroment</c> is started and cannot be changed afterwards.
+        /// Setting thread pool size is an advanced setting and you should only use it if you know what you are doing.
+        /// Most users should rely on the default value provided by gRPC library.
+        /// Note: this method is part of an experimental API that can change or be removed without any prior notice.
+        /// </summary>
+        public static void SetThreadPoolSize(int threadCount)
+        {
+            lock (staticLock)
+            {
+                GrpcPreconditions.CheckState(instance == null, "Can only be set before GrpcEnvironment is initialized");
+                GrpcPreconditions.CheckArgument(threadCount > 0, "threadCount needs to be a positive number");
+                customThreadPoolSize = threadCount;
+            }
+        }
+
+        /// <summary>
         /// Creates gRPC environment.
         /// </summary>
         private GrpcEnvironment()
         {
             GrpcNativeInit();
             completionRegistry = new CompletionRegistry(this);
-            threadPool = new GrpcThreadPool(this, THREAD_POOL_SIZE);
+            threadPool = new GrpcThreadPool(this, GetThreadPoolSizeOrDefault());
             threadPool.Start();
         }
 
@@ -200,5 +218,17 @@ namespace Grpc.Core
 
             debugStats.CheckOK();
         }
+
+        private int GetThreadPoolSizeOrDefault()
+        {
+            if (customThreadPoolSize.HasValue)
+            {
+                return customThreadPoolSize.Value;
+            }
+            // In systems with many cores, use half of the cores for GrpcThreadPool
+            // and the other half for .NET thread pool. This heuristic definitely needs
+            // more work, but seems to work reasonably well for a start.
+            return Math.Max(MinDefaultThreadPoolSize, Environment.ProcessorCount / 2);
+        }
     }
 }
diff --git a/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs b/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
index eafe2ccab8..b1566b44a7 100644
--- a/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
+++ b/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
@@ -139,8 +139,11 @@ namespace Grpc.Core.Internal
         /// Sends call result status, indicating we are done with writes.
         /// Sending a status different from StatusCode.OK will also implicitly cancel the call.
         /// </summary>
-        public Task SendStatusFromServerAsync(Status status, Metadata trailers)
+        public Task SendStatusFromServerAsync(Status status, Metadata trailers, Tuple<TResponse, WriteFlags> optionalWrite)
         {
+            byte[] payload = optionalWrite != null ? UnsafeSerialize(optionalWrite.Item1) : null;
+            var writeFlags = optionalWrite != null ? optionalWrite.Item2 : default(WriteFlags);
+
             lock (myLock)
             {
                 GrpcPreconditions.CheckState(started);
@@ -149,11 +152,16 @@ namespace Grpc.Core.Internal
 
                 using (var metadataArray = MetadataArraySafeHandle.Create(trailers))
                 {
-                    call.StartSendStatusFromServer(HandleSendStatusFromServerFinished, status, metadataArray, !initialMetadataSent);
+                    call.StartSendStatusFromServer(HandleSendStatusFromServerFinished, status, metadataArray, !initialMetadataSent,
+                        payload, writeFlags);
                 }
                 halfcloseRequested = true;
                 initialMetadataSent = true;
                 sendStatusFromServerTcs = new TaskCompletionSource<object>();
+                if (optionalWrite != null)
+                {
+                    streamingWritesCounter++;
+                }
                 return sendStatusFromServerTcs.Task;
             }
         }
diff --git a/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs b/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs
index 500653ba5d..244b97d4a4 100644
--- a/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs
@@ -135,13 +135,16 @@ namespace Grpc.Core.Internal
             }
         }
 
-        public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
+        public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata,
+            byte[] optionalPayload, WriteFlags writeFlags)
         {
             using (completionQueue.NewScope())
             {
                 var ctx = BatchContextSafeHandle.Create();
+                var optionalPayloadLength = optionalPayload != null ? new UIntPtr((ulong)optionalPayload.Length) : UIntPtr.Zero;
                 completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
-                Native.grpcsharp_call_send_status_from_server(this, ctx, status.StatusCode, status.Detail, metadataArray, sendEmptyInitialMetadata).CheckOk();
+                Native.grpcsharp_call_send_status_from_server(this, ctx, status.StatusCode, status.Detail, metadataArray, sendEmptyInitialMetadata,
+                    optionalPayload, optionalPayloadLength, writeFlags).CheckOk();
             }
         }
 
diff --git a/src/csharp/Grpc.Core/Internal/INativeCall.cs b/src/csharp/Grpc.Core/Internal/INativeCall.cs
index cbef599139..cd3719cb50 100644
--- a/src/csharp/Grpc.Core/Internal/INativeCall.cs
+++ b/src/csharp/Grpc.Core/Internal/INativeCall.cs
@@ -78,7 +78,7 @@ namespace Grpc.Core.Internal
 
         void StartSendCloseFromClient(SendCompletionHandler callback);
 
-        void StartSendStatusFromServer(SendCompletionHandler callback, Grpc.Core.Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata);
+        void StartSendStatusFromServer(SendCompletionHandler callback, Grpc.Core.Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata, byte[] optionalPayload, Grpc.Core.WriteFlags writeFlags);
 
         void StartServerSide(ReceivedCloseOnServerHandler callback);
     }
diff --git a/src/csharp/Grpc.Core/Internal/NativeMethods.cs b/src/csharp/Grpc.Core/Internal/NativeMethods.cs
index 9ee0ba3bc0..c277c73ef0 100644
--- a/src/csharp/Grpc.Core/Internal/NativeMethods.cs
+++ b/src/csharp/Grpc.Core/Internal/NativeMethods.cs
@@ -421,20 +421,21 @@ namespace Grpc.Core.Internal
             public delegate GRPCCallError grpcsharp_call_cancel_delegate(CallSafeHandle call);
             public delegate GRPCCallError grpcsharp_call_cancel_with_status_delegate(CallSafeHandle call, StatusCode status, string description);
             public delegate GRPCCallError grpcsharp_call_start_unary_delegate(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
             public delegate GRPCCallError grpcsharp_call_start_client_streaming_delegate(CallSafeHandle call,
                 BatchContextSafeHandle ctx, MetadataArraySafeHandle metadataArray);
             public delegate GRPCCallError grpcsharp_call_start_server_streaming_delegate(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len,
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen,
                 MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
             public delegate GRPCCallError grpcsharp_call_start_duplex_streaming_delegate(CallSafeHandle call,
                 BatchContextSafeHandle ctx, MetadataArraySafeHandle metadataArray);
             public delegate GRPCCallError grpcsharp_call_send_message_delegate(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len, WriteFlags writeFlags, bool sendEmptyInitialMetadata);
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen, WriteFlags writeFlags, bool sendEmptyInitialMetadata);
             public delegate GRPCCallError grpcsharp_call_send_close_from_client_delegate(CallSafeHandle call,
                 BatchContextSafeHandle ctx);
             public delegate GRPCCallError grpcsharp_call_send_status_from_server_delegate(CallSafeHandle call,
-                BatchContextSafeHandle ctx, StatusCode statusCode, string statusMessage, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata);
+                BatchContextSafeHandle ctx, StatusCode statusCode, string statusMessage, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata,
+                byte[] optionalSendBuffer, UIntPtr optionalSendBufferLen, WriteFlags writeFlags);
             public delegate GRPCCallError grpcsharp_call_recv_message_delegate(CallSafeHandle call,
                 BatchContextSafeHandle ctx);
             public delegate GRPCCallError grpcsharp_call_recv_initial_metadata_delegate(CallSafeHandle call,
@@ -593,7 +594,7 @@ namespace Grpc.Core.Internal
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_start_unary(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_start_client_streaming(CallSafeHandle call,
@@ -601,7 +602,7 @@ namespace Grpc.Core.Internal
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_start_server_streaming(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len,
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen,
                 MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
 
             [DllImport("grpc_csharp_ext.dll")]
@@ -610,7 +611,7 @@ namespace Grpc.Core.Internal
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_send_message(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] send_buffer, UIntPtr send_buffer_len, WriteFlags writeFlags, bool sendEmptyInitialMetadata);
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen, WriteFlags writeFlags, bool sendEmptyInitialMetadata);
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_send_close_from_client(CallSafeHandle call,
@@ -618,7 +619,8 @@ namespace Grpc.Core.Internal
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_send_status_from_server(CallSafeHandle call,
-                BatchContextSafeHandle ctx, StatusCode statusCode, string statusMessage, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata);
+                BatchContextSafeHandle ctx, StatusCode statusCode, string statusMessage, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata,
+                byte[] optionalSendBuffer, UIntPtr optionalSendBufferLen, WriteFlags writeFlags);
 
             [DllImport("grpc_csharp_ext.dll")]
             public static extern GRPCCallError grpcsharp_call_recv_message(CallSafeHandle call,
diff --git a/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs b/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
index 00d82d51e8..85b7a4b01e 100644
--- a/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
@@ -75,27 +75,32 @@ namespace Grpc.Core.Internal
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
 
             Status status;
+            Tuple<TResponse,WriteFlags> responseTuple = null;
             var context = HandlerUtils.NewContext(newRpc, asyncCall.Peer, responseStream, asyncCall.CancellationToken);
             try
             {
                 GrpcPreconditions.CheckArgument(await requestStream.MoveNext().ConfigureAwait(false));
                 var request = requestStream.Current;
-                var result = await handler(request, context).ConfigureAwait(false);
+                var response = await handler(request, context).ConfigureAwait(false);
                 status = context.Status;
-                await responseStream.WriteAsync(result).ConfigureAwait(false);
+                responseTuple = Tuple.Create(response, HandlerUtils.GetWriteFlags(context.WriteOptions));
             } 
             catch (Exception e)
             {
-                Logger.Error(e, "Exception occured in handler.");
+                if (!(e is RpcException))
+                {
+                    Logger.Warning(e, "Exception occured in handler.");
+                }
                 status = HandlerUtils.StatusFromException(e);
             }
             try
             {
-                await asyncCall.SendStatusFromServerAsync(status, context.ResponseTrailers).ConfigureAwait(false);
+                await asyncCall.SendStatusFromServerAsync(status, context.ResponseTrailers, responseTuple).ConfigureAwait(false);
             }
-            catch (OperationCanceledException)
+            catch (Exception)
             {
-                // Call has been already cancelled.
+                asyncCall.Cancel();
+                throw;
             }
             await finishedTask.ConfigureAwait(false);
         }
@@ -139,17 +144,21 @@ namespace Grpc.Core.Internal
             }
             catch (Exception e)
             {
-                Logger.Error(e, "Exception occured in handler.");
+                if (!(e is RpcException))
+                {
+                    Logger.Warning(e, "Exception occured in handler.");
+                }
                 status = HandlerUtils.StatusFromException(e);
             }
 
             try
             {
-                await asyncCall.SendStatusFromServerAsync(status, context.ResponseTrailers).ConfigureAwait(false);
+                await asyncCall.SendStatusFromServerAsync(status, context.ResponseTrailers, null).ConfigureAwait(false);
             }
-            catch (OperationCanceledException)
+            catch (Exception)
             {
-                // Call has been already cancelled.
+                asyncCall.Cancel();
+                throw;
             }
             await finishedTask.ConfigureAwait(false);
         }
@@ -183,33 +192,31 @@ namespace Grpc.Core.Internal
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
 
             Status status;
+            Tuple<TResponse,WriteFlags> responseTuple = null;
             var context = HandlerUtils.NewContext(newRpc, asyncCall.Peer, responseStream, asyncCall.CancellationToken);
             try
             {
-                var result = await handler(requestStream, context).ConfigureAwait(false);
+                var response = await handler(requestStream, context).ConfigureAwait(false);
                 status = context.Status;
-                try
-                {
-                    await responseStream.WriteAsync(result).ConfigureAwait(false);
-                }
-                catch (OperationCanceledException)
-                {
-                    status = Status.DefaultCancelled;
-                }
+                responseTuple = Tuple.Create(response, HandlerUtils.GetWriteFlags(context.WriteOptions));
             }
             catch (Exception e)
             {
-                Logger.Error(e, "Exception occured in handler.");
+                if (!(e is RpcException))
+                {
+                    Logger.Warning(e, "Exception occured in handler.");
+                }
                 status = HandlerUtils.StatusFromException(e);
             }
 
             try
             {
-                await asyncCall.SendStatusFromServerAsync(status, context.ResponseTrailers).ConfigureAwait(false);
+                await asyncCall.SendStatusFromServerAsync(status, context.ResponseTrailers, responseTuple).ConfigureAwait(false);
             }
-            catch (OperationCanceledException)
+            catch (Exception)
             {
-                // Call has been already cancelled.
+                asyncCall.Cancel();
+                throw;
             }
             await finishedTask.ConfigureAwait(false);
         }
@@ -251,16 +258,20 @@ namespace Grpc.Core.Internal
             }
             catch (Exception e)
             {
-                Logger.Error(e, "Exception occured in handler.");
+                if (!(e is RpcException))
+                {
+                    Logger.Warning(e, "Exception occured in handler.");
+                }
                 status = HandlerUtils.StatusFromException(e);
             }
             try
             {
-                await asyncCall.SendStatusFromServerAsync(status, context.ResponseTrailers).ConfigureAwait(false);
+                await asyncCall.SendStatusFromServerAsync(status, context.ResponseTrailers, null).ConfigureAwait(false);
             }
-            catch (OperationCanceledException)
+            catch (Exception)
             {
-                // Call has been already cancelled.
+                asyncCall.Cancel();
+                throw;
             }
             await finishedTask.ConfigureAwait(false);
         }
@@ -278,7 +289,7 @@ namespace Grpc.Core.Internal
             
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
-            await asyncCall.SendStatusFromServerAsync(new Status(StatusCode.Unimplemented, ""), Metadata.Empty).ConfigureAwait(false);
+            await asyncCall.SendStatusFromServerAsync(new Status(StatusCode.Unimplemented, ""), Metadata.Empty, null).ConfigureAwait(false);
             await finishedTask.ConfigureAwait(false);
         }
     }
@@ -297,6 +308,11 @@ namespace Grpc.Core.Internal
             return new Status(StatusCode.Unknown, "Exception was thrown by handler.");
         }
 
+        public static WriteFlags GetWriteFlags(WriteOptions writeOptions)
+        {
+            return writeOptions != null ? writeOptions.Flags : default(WriteFlags);
+        }
+
         public static ServerCallContext NewContext<TRequest, TResponse>(ServerRpcNew newRpc, string peer, ServerResponseStream<TRequest, TResponse> serverResponseStream, CancellationToken cancellationToken)
             where TRequest : class
             where TResponse : class
diff --git a/src/csharp/Grpc.Core/Server.cs b/src/csharp/Grpc.Core/Server.cs
index 5b61b7f060..d538a4671f 100644
--- a/src/csharp/Grpc.Core/Server.cs
+++ b/src/csharp/Grpc.Core/Server.cs
@@ -48,6 +48,7 @@ namespace Grpc.Core
     /// </summary>
     public class Server
     {
+        const int InitialAllowRpcTokenCount = 10;
         static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<Server>();
 
         readonly AtomicCounter activeCallCounter = new AtomicCounter();
@@ -65,7 +66,7 @@ namespace Grpc.Core
         readonly TaskCompletionSource<object> shutdownTcs = new TaskCompletionSource<object>();
 
         bool startRequested;
-        bool shutdownRequested;
+        volatile bool shutdownRequested;
 
         /// <summary>
         /// Create a new server.
@@ -129,7 +130,13 @@ namespace Grpc.Core
                 startRequested = true;
                 
                 handle.Start();
-                AllowOneRpc();
+
+                // Starting with more than one AllowOneRpc tokens can significantly increase
+                // unary RPC throughput.
+                for (int i = 0; i < InitialAllowRpcTokenCount; i++)
+                {
+                    AllowOneRpc();
+                }
             }
         }
 
@@ -239,12 +246,9 @@ namespace Grpc.Core
         /// </summary>
         private void AllowOneRpc()
         {
-            lock (myLock)
+            if (!shutdownRequested)
             {
-                if (!shutdownRequested)
-                {
-                    handle.RequestCall(HandleNewServerRpc, environment);
-                }
+                handle.RequestCall(HandleNewServerRpc, environment);
             }
         }
 
@@ -283,6 +287,8 @@ namespace Grpc.Core
         /// </summary>
         private void HandleNewServerRpc(bool success, BatchContextSafeHandle ctx)
         {
+			Task.Run(() => AllowOneRpc());
+
             if (success)
             {
                 ServerRpcNew newRpc = ctx.GetServerRpcNew(this);
@@ -290,11 +296,9 @@ namespace Grpc.Core
                 // after server shutdown, the callback returns with null call
                 if (!newRpc.Call.IsInvalid)
                 {
-                    Task.Run(async () => await HandleCallAsync(newRpc)).ConfigureAwait(false);
+                    HandleCallAsync(newRpc);  // we don't need to await.
                 }
             }
-
-            AllowOneRpc();
         }
 
         /// <summary>
diff --git a/src/csharp/Grpc.Core/VersionInfo.cs b/src/csharp/Grpc.Core/VersionInfo.cs
index f7a9cb9c1c..e1609341d9 100644
--- a/src/csharp/Grpc.Core/VersionInfo.cs
+++ b/src/csharp/Grpc.Core/VersionInfo.cs
@@ -48,11 +48,11 @@ namespace Grpc.Core
         /// <summary>
         /// Current <c>AssemblyFileVersion</c> of gRPC C# assemblies
         /// </summary>
-        public const string CurrentAssemblyFileVersion = "0.14.0.0";
+        public const string CurrentAssemblyFileVersion = "0.15.0.0";
 
         /// <summary>
         /// Current version of gRPC C#
         /// </summary>
-        public const string CurrentVersion = "0.14.0-dev";
+        public const string CurrentVersion = "0.15.0-dev";
     }
 }
diff --git a/src/csharp/Grpc.Examples/MathGrpc.cs b/src/csharp/Grpc.Examples/MathGrpc.cs
index 2d3034d28b..d700a18778 100644
--- a/src/csharp/Grpc.Examples/MathGrpc.cs
+++ b/src/csharp/Grpc.Examples/MathGrpc.cs
@@ -151,25 +151,25 @@ namespace Math {
       ///  Div divides args.dividend by args.divisor and returns the quotient and
       ///  remainder.
       /// </summary>
-      Task<global::Math.DivReply> Div(global::Math.DivArgs request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Math.DivReply> Div(global::Math.DivArgs request, ServerCallContext context);
       /// <summary>
       ///  DivMany accepts an arbitrary number of division args from the client stream
       ///  and sends back the results in the reply stream.  The stream continues until
       ///  the client closes its end; the server does the same after sending all the
       ///  replies.  The stream ends immediately if either end aborts.
       /// </summary>
-      Task DivMany(IAsyncStreamReader<global::Math.DivArgs> requestStream, IServerStreamWriter<global::Math.DivReply> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task DivMany(IAsyncStreamReader<global::Math.DivArgs> requestStream, IServerStreamWriter<global::Math.DivReply> responseStream, ServerCallContext context);
       /// <summary>
       ///  Fib generates numbers in the Fibonacci sequence.  If args.limit > 0, Fib
       ///  generates up to limit numbers; otherwise it continues until the call is
       ///  canceled.  Unlike Fib above, Fib has no final FibReply.
       /// </summary>
-      Task Fib(global::Math.FibArgs request, IServerStreamWriter<global::Math.Num> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task Fib(global::Math.FibArgs request, IServerStreamWriter<global::Math.Num> responseStream, ServerCallContext context);
       /// <summary>
       ///  Sum sums a stream of numbers, returning the final result once the stream
       ///  is closed.
       /// </summary>
-      Task<global::Math.Num> Sum(IAsyncStreamReader<global::Math.Num> requestStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Math.Num> Sum(IAsyncStreamReader<global::Math.Num> requestStream, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of Math</summary>
@@ -179,7 +179,7 @@ namespace Math {
       ///  Div divides args.dividend by args.divisor and returns the quotient and
       ///  remainder.
       /// </summary>
-      public virtual Task<global::Math.DivReply> Div(global::Math.DivArgs request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Math.DivReply> Div(global::Math.DivArgs request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -190,7 +190,7 @@ namespace Math {
       ///  the client closes its end; the server does the same after sending all the
       ///  replies.  The stream ends immediately if either end aborts.
       /// </summary>
-      public virtual Task DivMany(IAsyncStreamReader<global::Math.DivArgs> requestStream, IServerStreamWriter<global::Math.DivReply> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task DivMany(IAsyncStreamReader<global::Math.DivArgs> requestStream, IServerStreamWriter<global::Math.DivReply> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -200,7 +200,7 @@ namespace Math {
       ///  generates up to limit numbers; otherwise it continues until the call is
       ///  canceled.  Unlike Fib above, Fib has no final FibReply.
       /// </summary>
-      public virtual Task Fib(global::Math.FibArgs request, IServerStreamWriter<global::Math.Num> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task Fib(global::Math.FibArgs request, IServerStreamWriter<global::Math.Num> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -209,7 +209,7 @@ namespace Math {
       ///  Sum sums a stream of numbers, returning the final result once the stream
       ///  is closed.
       /// </summary>
-      public virtual Task<global::Math.Num> Sum(IAsyncStreamReader<global::Math.Num> requestStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Math.Num> Sum(IAsyncStreamReader<global::Math.Num> requestStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
diff --git a/src/csharp/Grpc.HealthCheck/HealthGrpc.cs b/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
index 967d1170be..51c6a39b1d 100644
--- a/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
+++ b/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
@@ -72,13 +72,13 @@ namespace Grpc.Health.V1 {
     [System.Obsolete("Service implementations should inherit from the generated abstract base class instead.")]
     public interface IHealth
     {
-      Task<global::Grpc.Health.V1.HealthCheckResponse> Check(global::Grpc.Health.V1.HealthCheckRequest request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Health.V1.HealthCheckResponse> Check(global::Grpc.Health.V1.HealthCheckRequest request, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of Health</summary>
     public abstract class HealthBase
     {
-      public virtual Task<global::Grpc.Health.V1.HealthCheckResponse> Check(global::Grpc.Health.V1.HealthCheckRequest request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Health.V1.HealthCheckResponse> Check(global::Grpc.Health.V1.HealthCheckRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
diff --git a/src/csharp/Grpc.IntegrationTesting/ClientRunners.cs b/src/csharp/Grpc.IntegrationTesting/ClientRunners.cs
index b4572756f2..9eaf6bf7ce 100644
--- a/src/csharp/Grpc.IntegrationTesting/ClientRunners.cs
+++ b/src/csharp/Grpc.IntegrationTesting/ClientRunners.cs
@@ -142,8 +142,7 @@ namespace Grpc.IntegrationTesting
                 for (int i = 0; i < outstandingRpcsPerChannel; i++)
                 {
                     var timer = CreateTimer(loadParams, 1.0 / this.channels.Count / outstandingRpcsPerChannel);
-                    var threadBody = GetThreadBody(channel, timer);
-                    this.runnerTasks.Add(Task.Factory.StartNew(threadBody, TaskCreationOptions.LongRunning));
+                    this.runnerTasks.Add(RunClientAsync(channel, timer));
                 }
             }
         }
@@ -269,38 +268,30 @@ namespace Grpc.IntegrationTesting
             }
         }
 
-        private Action GetThreadBody(Channel channel, IInterarrivalTimer timer)
+        private Task RunClientAsync(Channel channel, IInterarrivalTimer timer)
         {
             if (payloadConfig.PayloadCase == PayloadConfig.PayloadOneofCase.BytebufParams)
             {
                 GrpcPreconditions.CheckArgument(clientType == ClientType.ASYNC_CLIENT, "Generic client only supports async API");
                 GrpcPreconditions.CheckArgument(rpcType == RpcType.STREAMING, "Generic client only supports streaming calls");
-                return () =>
-                {
-                    RunGenericStreamingAsync(channel, timer).Wait();
-                };
+                return RunGenericStreamingAsync(channel, timer);
             }
 
             GrpcPreconditions.CheckNotNull(payloadConfig.SimpleParams);
             if (clientType == ClientType.SYNC_CLIENT)
             {
                 GrpcPreconditions.CheckArgument(rpcType == RpcType.UNARY, "Sync client can only be used for Unary calls in C#");
-                return () => RunUnary(channel, timer);
+                // create a dedicated thread for the synchronous client
+                return Task.Factory.StartNew(() => RunUnary(channel, timer), TaskCreationOptions.LongRunning);
             }
             else if (clientType == ClientType.ASYNC_CLIENT)
             {
                 switch (rpcType)
                 {
                     case RpcType.UNARY:
-                        return () =>
-                        {
-                            RunUnaryAsync(channel, timer).Wait();
-                        };
+                        return RunUnaryAsync(channel, timer);
                     case RpcType.STREAMING:
-                        return () =>
-                        {
-                            RunStreamingPingPongAsync(channel, timer).Wait();
-                        };
+                        return RunStreamingPingPongAsync(channel, timer);
                 }
             }
             throw new ArgumentException("Unsupported configuration.");
diff --git a/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs b/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
index aa4f1c5c3e..9d31d1c514 100644
--- a/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
@@ -112,11 +112,11 @@ namespace Grpc.Testing {
       ///  Returns the values of all the gauges that are currently being maintained by
       ///  the service
       /// </summary>
-      Task GetAllGauges(global::Grpc.Testing.EmptyMessage request, IServerStreamWriter<global::Grpc.Testing.GaugeResponse> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task GetAllGauges(global::Grpc.Testing.EmptyMessage request, IServerStreamWriter<global::Grpc.Testing.GaugeResponse> responseStream, ServerCallContext context);
       /// <summary>
       ///  Returns the value of one gauge
       /// </summary>
-      Task<global::Grpc.Testing.GaugeResponse> GetGauge(global::Grpc.Testing.GaugeRequest request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.GaugeResponse> GetGauge(global::Grpc.Testing.GaugeRequest request, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of MetricsService</summary>
@@ -126,7 +126,7 @@ namespace Grpc.Testing {
       ///  Returns the values of all the gauges that are currently being maintained by
       ///  the service
       /// </summary>
-      public virtual Task GetAllGauges(global::Grpc.Testing.EmptyMessage request, IServerStreamWriter<global::Grpc.Testing.GaugeResponse> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task GetAllGauges(global::Grpc.Testing.EmptyMessage request, IServerStreamWriter<global::Grpc.Testing.GaugeResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -134,7 +134,7 @@ namespace Grpc.Testing {
       /// <summary>
       ///  Returns the value of one gauge
       /// </summary>
-      public virtual Task<global::Grpc.Testing.GaugeResponse> GetGauge(global::Grpc.Testing.GaugeRequest request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.GaugeResponse> GetGauge(global::Grpc.Testing.GaugeRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
diff --git a/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs b/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
index 42bf5e0b58..f7071ebf6b 100644
--- a/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
@@ -111,12 +111,12 @@ namespace Grpc.Testing {
       ///  One request followed by one response.
       ///  The server returns the client payload as-is.
       /// </summary>
-      Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context);
       /// <summary>
       ///  One request followed by one response.
       ///  The server returns the client payload as-is.
       /// </summary>
-      Task StreamingCall(IAsyncStreamReader<global::Grpc.Testing.SimpleRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.SimpleResponse> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task StreamingCall(IAsyncStreamReader<global::Grpc.Testing.SimpleRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.SimpleResponse> responseStream, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of BenchmarkService</summary>
@@ -126,7 +126,7 @@ namespace Grpc.Testing {
       ///  One request followed by one response.
       ///  The server returns the client payload as-is.
       /// </summary>
-      public virtual Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -135,7 +135,7 @@ namespace Grpc.Testing {
       ///  One request followed by one response.
       ///  The server returns the client payload as-is.
       /// </summary>
-      public virtual Task StreamingCall(IAsyncStreamReader<global::Grpc.Testing.SimpleRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.SimpleResponse> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task StreamingCall(IAsyncStreamReader<global::Grpc.Testing.SimpleRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.SimpleResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -375,7 +375,7 @@ namespace Grpc.Testing {
       ///  and once the shutdown has finished, the OK status is sent to terminate
       ///  this RPC.
       /// </summary>
-      Task RunServer(IAsyncStreamReader<global::Grpc.Testing.ServerArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ServerStatus> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task RunServer(IAsyncStreamReader<global::Grpc.Testing.ServerArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ServerStatus> responseStream, ServerCallContext context);
       /// <summary>
       ///  Start client with specified workload.
       ///  First request sent specifies the ClientConfig followed by ClientStatus
@@ -384,15 +384,15 @@ namespace Grpc.Testing {
       ///  and once the shutdown has finished, the OK status is sent to terminate
       ///  this RPC.
       /// </summary>
-      Task RunClient(IAsyncStreamReader<global::Grpc.Testing.ClientArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ClientStatus> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task RunClient(IAsyncStreamReader<global::Grpc.Testing.ClientArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ClientStatus> responseStream, ServerCallContext context);
       /// <summary>
       ///  Just return the core count - unary call
       /// </summary>
-      Task<global::Grpc.Testing.CoreResponse> CoreCount(global::Grpc.Testing.CoreRequest request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.CoreResponse> CoreCount(global::Grpc.Testing.CoreRequest request, ServerCallContext context);
       /// <summary>
       ///  Quit this worker
       /// </summary>
-      Task<global::Grpc.Testing.Void> QuitWorker(global::Grpc.Testing.Void request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.Void> QuitWorker(global::Grpc.Testing.Void request, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of WorkerService</summary>
@@ -406,7 +406,7 @@ namespace Grpc.Testing {
       ///  and once the shutdown has finished, the OK status is sent to terminate
       ///  this RPC.
       /// </summary>
-      public virtual Task RunServer(IAsyncStreamReader<global::Grpc.Testing.ServerArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ServerStatus> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task RunServer(IAsyncStreamReader<global::Grpc.Testing.ServerArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ServerStatus> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -419,7 +419,7 @@ namespace Grpc.Testing {
       ///  and once the shutdown has finished, the OK status is sent to terminate
       ///  this RPC.
       /// </summary>
-      public virtual Task RunClient(IAsyncStreamReader<global::Grpc.Testing.ClientArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ClientStatus> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task RunClient(IAsyncStreamReader<global::Grpc.Testing.ClientArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ClientStatus> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -427,7 +427,7 @@ namespace Grpc.Testing {
       /// <summary>
       ///  Just return the core count - unary call
       /// </summary>
-      public virtual Task<global::Grpc.Testing.CoreResponse> CoreCount(global::Grpc.Testing.CoreRequest request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.CoreResponse> CoreCount(global::Grpc.Testing.CoreRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -435,7 +435,7 @@ namespace Grpc.Testing {
       /// <summary>
       ///  Quit this worker
       /// </summary>
-      public virtual Task<global::Grpc.Testing.Void> QuitWorker(global::Grpc.Testing.Void request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.Void> QuitWorker(global::Grpc.Testing.Void request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
diff --git a/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs b/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
index f1878cbb55..cf43a77118 100644
--- a/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
@@ -196,34 +196,34 @@ namespace Grpc.Testing {
       /// <summary>
       ///  One empty request followed by one empty response.
       /// </summary>
-      Task<global::Grpc.Testing.Empty> EmptyCall(global::Grpc.Testing.Empty request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> EmptyCall(global::Grpc.Testing.Empty request, ServerCallContext context);
       /// <summary>
       ///  One request followed by one response.
       /// </summary>
-      Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context);
       /// <summary>
       ///  One request followed by a sequence of responses (streamed download).
       ///  The server returns the payload with client desired type and sizes.
       /// </summary>
-      Task StreamingOutputCall(global::Grpc.Testing.StreamingOutputCallRequest request, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task StreamingOutputCall(global::Grpc.Testing.StreamingOutputCallRequest request, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
       /// <summary>
       ///  A sequence of requests followed by one response (streamed upload).
       ///  The server returns the aggregated size of client payload as the result.
       /// </summary>
-      Task<global::Grpc.Testing.StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<global::Grpc.Testing.StreamingInputCallRequest> requestStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<global::Grpc.Testing.StreamingInputCallRequest> requestStream, ServerCallContext context);
       /// <summary>
       ///  A sequence of requests with each request served by the server immediately.
       ///  As one request could lead to multiple responses, this interface
       ///  demonstrates the idea of full duplexing.
       /// </summary>
-      Task FullDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task FullDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
       /// <summary>
       ///  A sequence of requests followed by a sequence of responses.
       ///  The server buffers all the client requests and then serves them in order. A
       ///  stream of responses are returned to the client when the server starts with
       ///  first request.
       /// </summary>
-      Task HalfDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
+      global::System.Threading.Tasks.Task HalfDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of TestService</summary>
@@ -232,7 +232,7 @@ namespace Grpc.Testing {
       /// <summary>
       ///  One empty request followed by one empty response.
       /// </summary>
-      public virtual Task<global::Grpc.Testing.Empty> EmptyCall(global::Grpc.Testing.Empty request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> EmptyCall(global::Grpc.Testing.Empty request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -240,7 +240,7 @@ namespace Grpc.Testing {
       /// <summary>
       ///  One request followed by one response.
       /// </summary>
-      public virtual Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -249,7 +249,7 @@ namespace Grpc.Testing {
       ///  One request followed by a sequence of responses (streamed download).
       ///  The server returns the payload with client desired type and sizes.
       /// </summary>
-      public virtual Task StreamingOutputCall(global::Grpc.Testing.StreamingOutputCallRequest request, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task StreamingOutputCall(global::Grpc.Testing.StreamingOutputCallRequest request, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -258,7 +258,7 @@ namespace Grpc.Testing {
       ///  A sequence of requests followed by one response (streamed upload).
       ///  The server returns the aggregated size of client payload as the result.
       /// </summary>
-      public virtual Task<global::Grpc.Testing.StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<global::Grpc.Testing.StreamingInputCallRequest> requestStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<global::Grpc.Testing.StreamingInputCallRequest> requestStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -268,7 +268,7 @@ namespace Grpc.Testing {
       ///  As one request could lead to multiple responses, this interface
       ///  demonstrates the idea of full duplexing.
       /// </summary>
-      public virtual Task FullDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task FullDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -279,7 +279,7 @@ namespace Grpc.Testing {
       ///  stream of responses are returned to the client when the server starts with
       ///  first request.
       /// </summary>
-      public virtual Task HalfDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task HalfDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -525,7 +525,7 @@ namespace Grpc.Testing {
       /// <summary>
       ///  A call that no server should implement
       /// </summary>
-      Task<global::Grpc.Testing.Empty> UnimplementedCall(global::Grpc.Testing.Empty request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> UnimplementedCall(global::Grpc.Testing.Empty request, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of UnimplementedService</summary>
@@ -534,7 +534,7 @@ namespace Grpc.Testing {
       /// <summary>
       ///  A call that no server should implement
       /// </summary>
-      public virtual Task<global::Grpc.Testing.Empty> UnimplementedCall(global::Grpc.Testing.Empty request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> UnimplementedCall(global::Grpc.Testing.Empty request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
@@ -669,19 +669,19 @@ namespace Grpc.Testing {
     [System.Obsolete("Service implementations should inherit from the generated abstract base class instead.")]
     public interface IReconnectService
     {
-      Task<global::Grpc.Testing.Empty> Start(global::Grpc.Testing.ReconnectParams request, ServerCallContext context);
-      Task<global::Grpc.Testing.ReconnectInfo> Stop(global::Grpc.Testing.Empty request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> Start(global::Grpc.Testing.ReconnectParams request, ServerCallContext context);
+      global::System.Threading.Tasks.Task<global::Grpc.Testing.ReconnectInfo> Stop(global::Grpc.Testing.Empty request, ServerCallContext context);
     }
 
     /// <summary>Base class for server-side implementations of ReconnectService</summary>
     public abstract class ReconnectServiceBase
     {
-      public virtual Task<global::Grpc.Testing.Empty> Start(global::Grpc.Testing.ReconnectParams request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> Start(global::Grpc.Testing.ReconnectParams request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
-      public virtual Task<global::Grpc.Testing.ReconnectInfo> Stop(global::Grpc.Testing.Empty request, ServerCallContext context)
+      public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.ReconnectInfo> Stop(global::Grpc.Testing.Empty request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
diff --git a/src/csharp/build_packages.bat b/src/csharp/build_packages.bat
index 9a60be26b6..7520b0f81a 100644
--- a/src/csharp/build_packages.bat
+++ b/src/csharp/build_packages.bat
@@ -1,7 +1,7 @@
 @rem Builds gRPC NuGet packages
 
 @rem Current package versions
-set VERSION=0.14.0-dev
+set VERSION=0.15.0-dev
 set PROTOBUF_VERSION=3.0.0-beta2
 
 @rem Packages that depend on prerelease packages (like Google.Protobuf) need to have prerelease suffix as well.
diff --git a/src/csharp/ext/grpc_csharp_ext.c b/src/csharp/ext/grpc_csharp_ext.c
index aeef8a79e9..5b8ff9b819 100644
--- a/src/csharp/ext/grpc_csharp_ext.c
+++ b/src/csharp/ext/grpc_csharp_ext.c
@@ -715,10 +715,11 @@ grpcsharp_call_send_close_from_client(grpc_call *call,
 GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_send_status_from_server(
     grpc_call *call, grpcsharp_batch_context *ctx, grpc_status_code status_code,
     const char *status_details, grpc_metadata_array *trailing_metadata,
-    int32_t send_empty_initial_metadata) {
+    int32_t send_empty_initial_metadata, const char* optional_send_buffer,
+    size_t optional_send_buffer_len, uint32_t write_flags) {
   /* TODO: don't use magic number */
-  grpc_op ops[2];
-  size_t nops = send_empty_initial_metadata ? 2 : 1;
+  grpc_op ops[3];
+  size_t nops = 1;
   ops[0].op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   ops[0].data.send_status_from_server.status = status_code;
   ops[0].data.send_status_from_server.status_details =
@@ -731,12 +732,23 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_send_status_from_server(
       ctx->send_status_from_server.trailing_metadata.metadata;
   ops[0].flags = 0;
   ops[0].reserved = NULL;
-  ops[1].op = GRPC_OP_SEND_INITIAL_METADATA;
-  ops[1].data.send_initial_metadata.count = 0;
-  ops[1].data.send_initial_metadata.metadata = NULL;
-  ops[1].flags = 0;
-  ops[1].reserved = NULL;
-
+  if (optional_send_buffer) {
+    ops[nops].op = GRPC_OP_SEND_MESSAGE;
+    ctx->send_message = string_to_byte_buffer(optional_send_buffer,
+                                              optional_send_buffer_len);
+    ops[nops].data.send_message = ctx->send_message;
+    ops[nops].flags = write_flags;
+    ops[nops].reserved = NULL;
+    nops ++;
+  }
+  if (send_empty_initial_metadata) {
+    ops[nops].op = GRPC_OP_SEND_INITIAL_METADATA;
+    ops[nops].data.send_initial_metadata.count = 0;
+    ops[nops].data.send_initial_metadata.metadata = NULL;
+    ops[nops].flags = 0;
+    ops[nops].reserved = NULL;
+    nops++;
+  }
   return grpc_call_start_batch(call, ops, nops, ctx, NULL);
 }
 
diff --git a/src/node/test/math/math_server.js b/src/node/test/math/math_server.js
index fa05ed0165..5e3d1dd864 100644
--- a/src/node/test/math/math_server.js
+++ b/src/node/test/math/math_server.js
@@ -68,7 +68,7 @@ function mathDiv(call, cb) {
 function mathFib(stream) {
   // Here, call is a standard writable Node object Stream
   var previous = 0, current = 1;
-  for (var i = 0; i < stream.request.limit; i++) {
+  for (var i = 0; i < stream.request.getLimit(); i++) {
     var response = new math.Num();
     response.setNum(current);
     stream.write(response);
diff --git a/src/node/tools/package.json b/src/node/tools/package.json
index d98ed0b1fc..d4849c2e38 100644
--- a/src/node/tools/package.json
+++ b/src/node/tools/package.json
@@ -1,6 +1,6 @@
 {
   "name": "grpc-tools",
-  "version": "0.14.0-dev",
+  "version": "0.15.0-dev",
   "author": "Google Inc.",
   "description": "Tools for developing with gRPC on Node.js",
   "homepage": "http://www.grpc.io/",
@@ -16,8 +16,8 @@
     }
   ],
   "bin": {
-    "grpc-tools-protoc": "./bin/protoc.js",
-    "grpc-tools-plugin": "./bin/protoc_plugin.js"
+    "grpc_tools_node_protoc": "./bin/protoc.js",
+    "grpc_tools_node_protoc_plugin": "./bin/protoc_plugin.js"
   },
   "scripts": {
     "install": "./node_modules/.bin/node-pre-gyp install"
diff --git a/src/objective-c/BoringSSL.podspec b/src/objective-c/BoringSSL.podspec
index 4a6df910a7..7d1de80716 100644
--- a/src/objective-c/BoringSSL.podspec
+++ b/src/objective-c/BoringSSL.podspec
@@ -31,7 +31,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'BoringSSL'
-  s.version  = '2.0'
+  s.version  = '3.0'
   s.summary  = 'BoringSSL is a fork of OpenSSL that is designed to meet Google’s needs.'
   # Adapted from the homepage:
   s.description = <<-DESC
@@ -67,7 +67,7 @@ Pod::Spec.new do |s|
   s.authors  = 'Adam Langley', 'David Benjamin', 'Matt Braithwaite'
 
   s.source = { :git => 'https://boringssl.googlesource.com/boringssl',
-               :tag => 'version_for_cocoapods_2.0' }
+               :tag => 'version_for_cocoapods_3.0' }
 
   s.source_files = 'ssl/*.{h,c}',
                    'ssl/**/*.{h,c}',
diff --git a/src/php/tests/interop/interop_client.php b/src/php/tests/interop/interop_client.php
index aebf80f6bf..565bfce74f 100755
--- a/src/php/tests/interop/interop_client.php
+++ b/src/php/tests/interop/interop_client.php
@@ -1,7 +1,7 @@
 <?php
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -388,141 +388,158 @@ function timeoutOnSleepingServer($stub)
              'Call status was not DEADLINE_EXCEEDED');
 }
 
-$args = getopt('', ['server_host:', 'server_port:', 'test_case:',
-                    'use_tls::', 'use_test_ca::',
-                    'server_host_override:', 'oauth_scope:',
-                    'default_service_account:', ]);
-if (!array_key_exists('server_host', $args)) {
-    throw new Exception('Missing argument: --server_host is required');
-}
-if (!array_key_exists('server_port', $args)) {
-    throw new Exception('Missing argument: --server_port is required');
-}
-if (!array_key_exists('test_case', $args)) {
-    throw new Exception('Missing argument: --test_case is required');
-}
-
-if ($args['server_port'] == 443) {
-    $server_address = $args['server_host'];
-} else {
-    $server_address = $args['server_host'].':'.$args['server_port'];
-}
+function _makeStub($args)
+{
+    if (!array_key_exists('server_host', $args)) {
+        throw new Exception('Missing argument: --server_host is required');
+    }
+    if (!array_key_exists('server_port', $args)) {
+        throw new Exception('Missing argument: --server_port is required');
+    }
+    if (!array_key_exists('test_case', $args)) {
+        throw new Exception('Missing argument: --test_case is required');
+    }
 
-$test_case = $args['test_case'];
+    if ($args['server_port'] == 443) {
+        $server_address = $args['server_host'];
+    } else {
+        $server_address = $args['server_host'].':'.$args['server_port'];
+    }
 
-$host_override = 'foo.test.google.fr';
-if (array_key_exists('server_host_override', $args)) {
-    $host_override = $args['server_host_override'];
-}
+    $test_case = $args['test_case'];
 
-$use_tls = false;
-if (array_key_exists('use_tls', $args) &&
-    $args['use_tls'] != 'false') {
-    $use_tls = true;
-}
+    $host_override = 'foo.test.google.fr';
+    if (array_key_exists('server_host_override', $args)) {
+        $host_override = $args['server_host_override'];
+    }
 
-$use_test_ca = false;
-if (array_key_exists('use_test_ca', $args) &&
-    $args['use_test_ca'] != 'false') {
-    $use_test_ca = true;
-}
+    $use_tls = false;
+    if (array_key_exists('use_tls', $args) &&
+        $args['use_tls'] != 'false') {
+        $use_tls = true;
+    }
 
-$opts = [];
+    $use_test_ca = false;
+    if (array_key_exists('use_test_ca', $args) &&
+        $args['use_test_ca'] != 'false') {
+        $use_test_ca = true;
+    }
 
-if ($use_tls) {
-    if ($use_test_ca) {
-        $ssl_credentials = Grpc\ChannelCredentials::createSsl(
-            file_get_contents(dirname(__FILE__).'/../data/ca.pem'));
+    $opts = [];
+
+    if ($use_tls) {
+        if ($use_test_ca) {
+            $ssl_credentials = Grpc\ChannelCredentials::createSsl(
+                file_get_contents(dirname(__FILE__).'/../data/ca.pem'));
+        } else {
+            $ssl_credentials = Grpc\ChannelCredentials::createSsl();
+        }
+        $opts['credentials'] = $ssl_credentials;
+        $opts['grpc.ssl_target_name_override'] = $host_override;
     } else {
-        $ssl_credentials = Grpc\ChannelCredentials::createSsl();
+        $opts['credentials'] = Grpc\ChannelCredentials::createInsecure();
     }
-    $opts['credentials'] = $ssl_credentials;
-    $opts['grpc.ssl_target_name_override'] = $host_override;
-} else {
-    $opts['credentials'] = Grpc\ChannelCredentials::createInsecure();
-}
 
-if (in_array($test_case, ['service_account_creds',
-    'compute_engine_creds', 'jwt_token_creds', ])) {
-    if ($test_case == 'jwt_token_creds') {
-        $auth_credentials = ApplicationDefaultCredentials::getCredentials();
-    } else {
+    if (in_array($test_case, ['service_account_creds',
+                              'compute_engine_creds', 'jwt_token_creds', ])) {
+        if ($test_case == 'jwt_token_creds') {
+            $auth_credentials = ApplicationDefaultCredentials::getCredentials();
+        } else {
+            $auth_credentials = ApplicationDefaultCredentials::getCredentials(
+                $args['oauth_scope']
+            );
+        }
+        $opts['update_metadata'] = $auth_credentials->getUpdateMetadataFunc();
+    }
+
+    if ($test_case == 'oauth2_auth_token') {
         $auth_credentials = ApplicationDefaultCredentials::getCredentials(
             $args['oauth_scope']
         );
+        $token = $auth_credentials->fetchAuthToken();
+        $update_metadata =
+            function ($metadata,
+                      $authUri = null,
+                      ClientInterface $client = null) use ($token) {
+                $metadata_copy = $metadata;
+                $metadata_copy[CredentialsLoader::AUTH_METADATA_KEY] =
+                    [sprintf('%s %s',
+                             $token['token_type'],
+                             $token['access_token'])];
+
+                return $metadata_copy;
+            };
+        $opts['update_metadata'] = $update_metadata;
     }
-    $opts['update_metadata'] = $auth_credentials->getUpdateMetadataFunc();
+
+    $stub = new grpc\testing\TestServiceClient($server_address, $opts);
+
+    return $stub;
 }
 
-if ($test_case == 'oauth2_auth_token') {
-    $auth_credentials = ApplicationDefaultCredentials::getCredentials(
-        $args['oauth_scope']
-    );
-    $token = $auth_credentials->fetchAuthToken();
-    $update_metadata =
-        function ($metadata,
-                  $authUri = null,
-                  ClientInterface $client = null) use ($token) {
-            $metadata_copy = $metadata;
-            $metadata_copy[CredentialsLoader::AUTH_METADATA_KEY] =
-                [sprintf('%s %s',
-                         $token['token_type'],
-                         $token['access_token'])];
-
-            return $metadata_copy;
-        };
-    $opts['update_metadata'] = $update_metadata;
+function interop_main($args, $stub = false) {
+    if (!$stub) {
+        $stub = _makeStub($args);
+    }
+
+    $test_case = $args['test_case'];
+    echo "Running test case $test_case\n";
+
+    switch ($test_case) {
+        case 'empty_unary':
+            emptyUnary($stub);
+            break;
+        case 'large_unary':
+            largeUnary($stub);
+            break;
+        case 'client_streaming':
+            clientStreaming($stub);
+            break;
+        case 'server_streaming':
+            serverStreaming($stub);
+            break;
+        case 'ping_pong':
+            pingPong($stub);
+            break;
+        case 'empty_stream':
+            emptyStream($stub);
+            break;
+        case 'cancel_after_begin':
+            cancelAfterBegin($stub);
+            break;
+        case 'cancel_after_first_response':
+            cancelAfterFirstResponse($stub);
+            break;
+        case 'timeout_on_sleeping_server':
+            timeoutOnSleepingServer($stub);
+            break;
+        case 'service_account_creds':
+            serviceAccountCreds($stub, $args);
+            break;
+        case 'compute_engine_creds':
+            computeEngineCreds($stub, $args);
+            break;
+        case 'jwt_token_creds':
+            jwtTokenCreds($stub, $args);
+            break;
+        case 'oauth2_auth_token':
+            oauth2AuthToken($stub, $args);
+            break;
+        case 'per_rpc_creds':
+            perRpcCreds($stub, $args);
+            break;
+        default:
+            echo "Unsupported test case $test_case\n";
+            exit(1);
+    }
+
+    return $stub;
 }
 
-$stub = new grpc\testing\TestServiceClient($server_address, $opts);
-
-echo "Connecting to $server_address\n";
-echo "Running test case $test_case\n";
-
-switch ($test_case) {
-    case 'empty_unary':
-        emptyUnary($stub);
-        break;
-    case 'large_unary':
-        largeUnary($stub);
-        break;
-    case 'client_streaming':
-        clientStreaming($stub);
-        break;
-    case 'server_streaming':
-        serverStreaming($stub);
-        break;
-    case 'ping_pong':
-        pingPong($stub);
-        break;
-    case 'empty_stream':
-        emptyStream($stub);
-        break;
-    case 'cancel_after_begin':
-        cancelAfterBegin($stub);
-        break;
-    case 'cancel_after_first_response':
-        cancelAfterFirstResponse($stub);
-        break;
-    case 'timeout_on_sleeping_server':
-        timeoutOnSleepingServer($stub);
-        break;
-    case 'service_account_creds':
-        serviceAccountCreds($stub, $args);
-        break;
-    case 'compute_engine_creds':
-        computeEngineCreds($stub, $args);
-        break;
-    case 'jwt_token_creds':
-        jwtTokenCreds($stub, $args);
-        break;
-    case 'oauth2_auth_token':
-        oauth2AuthToken($stub, $args);
-        break;
-    case 'per_rpc_creds':
-        perRpcCreds($stub, $args);
-        break;
-    default:
-        echo "Unsupported test case $test_case\n";
-        exit(1);
+if (isset($_SERVER['PHP_SELF']) && preg_match('/interop_client/', $_SERVER['PHP_SELF'])) {
+    $args = getopt('', ['server_host:', 'server_port:', 'test_case:',
+                        'use_tls::', 'use_test_ca::',
+                        'server_host_override:', 'oauth_scope:',
+                        'default_service_account:', ]);
+    interop_main($args);
 }
diff --git a/src/php/tests/interop/metrics_client.php b/src/php/tests/interop/metrics_client.php
new file mode 100644
index 0000000000..46f4212f77
--- /dev/null
+++ b/src/php/tests/interop/metrics_client.php
@@ -0,0 +1,49 @@
+<?php
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+$args = getopt('', ['metrics_server_address:', 'total_only::']);
+$parts = explode(':', $args['metrics_server_address']);
+$server_host = $parts[0];
+$server_port = (count($parts) == 2) ? $parts[1] : '';
+
+$socket = socket_create(AF_INET, SOCK_STREAM, 0);
+if (@!socket_connect($socket, $server_host, $server_port)) {
+  echo "Cannot connect to merics server...\n";
+  exit(1);
+}
+socket_write($socket, 'qps');
+while ($out = socket_read($socket, 1024)) {
+  echo "$out\n";
+}
+socket_close($socket);
diff --git a/src/php/tests/interop/stress_client.php b/src/php/tests/interop/stress_client.php
new file mode 100644
index 0000000000..2339f0d105
--- /dev/null
+++ b/src/php/tests/interop/stress_client.php
@@ -0,0 +1,116 @@
+<?php
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+include_once('interop_client.php');
+
+function stress_main($args) {
+  mt_srand();
+  set_time_limit(0);
+
+  // open socket to listen as metrics server
+  $socket = socket_create(AF_INET, SOCK_STREAM, 0);
+  socket_set_option($socket, SOL_SOCKET, SO_REUSEADDR, 1);
+  if (@!socket_bind($socket, 'localhost', $args['metrics_port'])) {
+    echo "Cannot create socket for metrics server...\n";
+    exit(1);
+  }
+  socket_listen($socket);
+  socket_set_nonblock($socket);
+
+  $start_time = microtime(true);
+  $count = 0;
+  $deadline = $args['test_duration_secs'] ?
+              ($start_time + $args['test_duration_secs']) : false;
+  $num_test_cases = count($args['test_cases']);
+  $stub = false;
+
+  while (true) {
+    $current_time = microtime(true);
+    if ($deadline && $current_time > $deadline) {
+      break;
+    }
+    if ($client_connection = socket_accept($socket)) {
+      // there is an incoming request, respond with qps metrics
+      $input = socket_read($client_connection, 1024);
+      $qps = round($count / ($current_time - $start_time));
+      socket_write($client_connection, "qps: $qps");
+      socket_close($client_connection);
+    } else {
+      // do actual work, run one interop test case
+      $args['test_case'] =
+          $args['test_cases'][mt_rand(0, $num_test_cases - 1)];
+      $stub = @interop_main($args, $stub);
+      $count++;
+    }
+  }
+  socket_close($socket);
+  echo "Number of interop tests run in $args[test_duration_secs] seconds: $count.\n";
+}
+
+// process command line arguments
+$raw_args = getopt('',
+  ['server_addresses::',
+   'test_cases:',
+   'metrics_port::',
+   'test_duration_secs::',
+   'num_channels_per_server::',
+   'num_stubs_per_channel::']);
+
+$args = [];
+
+if (empty($raw_args['server_addresses'])) {
+  $args['server_host'] = 'localhost';
+  $args['server_port'] = '8080';
+} else {
+  $parts = explode(':', $raw_args['server_addresses']);
+  $args['server_host'] = $parts[0];
+  $args['server_port'] = (count($parts) == 2) ? $parts[1] : '';
+}
+
+$args['metrics_port'] = empty($raw_args['metrics_port']) ?
+  '8081' : $args['metrics_port'];
+
+$args['test_duration_secs'] = empty($raw_args['test_duration_secs']) ||
+  $raw_args['test_duration_secs'] == -1 ?
+  false : $raw_args['test_duration_secs'];
+
+$test_cases = [];
+$test_case_strs = explode(',', $raw_args['test_cases']);
+foreach ($test_case_strs as $test_case_str) {
+  $parts = explode(':', $test_case_str);
+  $test_cases = array_merge($test_cases, array_fill(0, $parts[1], $parts[0]));
+}
+$args['test_cases'] = $test_cases;
+
+stress_main($args);
diff --git a/src/proto/grpc/lb/v0/load_balancer.options b/src/proto/grpc/lb/v0/load_balancer.options
deleted file mode 100644
index 6d4528f838..0000000000
--- a/src/proto/grpc/lb/v0/load_balancer.options
+++ /dev/null
@@ -1,6 +0,0 @@
-grpc.lb.v0.InitialLoadBalanceRequest.name max_size:128
-grpc.lb.v0.InitialLoadBalanceResponse.client_config max_size:64
-grpc.lb.v0.InitialLoadBalanceResponse.load_balancer_delegate max_size:64
-grpc.lb.v0.Server.ip_address max_size:46
-grpc.lb.v0.Server.load_balance_token max_size:64
-load_balancer.proto no_unions:true
diff --git a/src/proto/grpc/lb/v1/load_balancer.options b/src/proto/grpc/lb/v1/load_balancer.options
new file mode 100644
index 0000000000..d90366996e
--- /dev/null
+++ b/src/proto/grpc/lb/v1/load_balancer.options
@@ -0,0 +1,6 @@
+grpc.lb.v1.InitialLoadBalanceRequest.name max_size:128
+grpc.lb.v1.InitialLoadBalanceResponse.client_config max_size:64
+grpc.lb.v1.InitialLoadBalanceResponse.load_balancer_delegate max_size:64
+grpc.lb.v1.Server.ip_address max_size:46
+grpc.lb.v1.Server.load_balance_token max_size:64
+load_balancer.proto no_unions:true
diff --git a/src/proto/grpc/lb/v0/load_balancer.proto b/src/proto/grpc/lb/v1/load_balancer.proto
index e88a4f8c4a..1bcad0b1d4 100644
--- a/src/proto/grpc/lb/v0/load_balancer.proto
+++ b/src/proto/grpc/lb/v1/load_balancer.proto
@@ -29,7 +29,7 @@
 
 syntax = "proto3";
 
-package grpc.lb.v0;
+package grpc.lb.v1;
 
 message Duration {
 
@@ -94,9 +94,8 @@ message LoadBalanceResponse {
 
 message InitialLoadBalanceResponse {
   oneof initial_response_type {
-    // Contains gRPC config options like RPC deadline or flow control.
-    // TODO(yetianx): Change to ClientConfig after it is defined.
-    string client_config = 1;
+    // TODO(zhangkun83): ClientConfig not yet defined
+    //ClientConfig client_config = 1;
 
     // This is an application layer redirect that indicates the client should
     // use the specified server for load balancing. When this field is set in
@@ -134,9 +133,7 @@ message Server {
   // An opaque token that is passed from the client to the server in metadata.
   // The server may expect this token to indicate that the request from the
   // client was load balanced.
-  // TODO(yetianx): Not used right now, and will be used after implementing
-  // load report.
-  bytes load_balance_token = 3;
+  string load_balance_token = 3;
 
   // Indicates whether this particular request should be dropped by the client
   // when this server is chosen from the list.
diff --git a/src/proto/grpc/testing/echo.proto b/src/proto/grpc/testing/echo.proto
index 0eef53a92a..c596aabfcc 100644
--- a/src/proto/grpc/testing/echo.proto
+++ b/src/proto/grpc/testing/echo.proto
@@ -45,3 +45,7 @@ service EchoTestService {
 service UnimplementedService {
   rpc Unimplemented(EchoRequest) returns (EchoResponse);
 }
+
+// A service without any rpc defined to test coverage.
+service NoRpcService {
+}
diff --git a/src/python/grpcio/README.rst b/src/python/grpcio/README.rst
index cb3f6b87fe..afc4fe6a37 100644
--- a/src/python/grpcio/README.rst
+++ b/src/python/grpcio/README.rst
@@ -48,6 +48,7 @@ package named :code:`python-dev`).
   $ export REPO_ROOT=grpc  # REPO_ROOT can be any directory of your choice
   $ git clone https://github.com/grpc/grpc.git $REPO_ROOT
   $ cd $REPO_ROOT
+  $ git submodule update --init
 
   # For the next two commands do `sudo pip install` if you get permission-denied errors
   $ pip install -rrequirements.txt
diff --git a/src/python/grpcio/grpc/__init__.py b/src/python/grpcio/grpc/__init__.py
index 7086519106..b844a14c48 100644
--- a/src/python/grpcio/grpc/__init__.py
+++ b/src/python/grpcio/grpc/__init__.py
@@ -1,4 +1,4 @@
-# Copyright 2015, Google Inc.
+# Copyright 2015-2016, Google Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -27,4 +27,5 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+__import__('pkg_resources').declare_namespace(__name__)
 
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index 0f0678a2cd..a411f45bbd 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -231,7 +231,7 @@ CORE_SOURCE_FILES = [
   'src/core/ext/transport/chttp2/server/insecure/server_chttp2.c',
   'src/core/ext/transport/chttp2/client/insecure/channel_create.c',
   'src/core/ext/lb_policy/grpclb/load_balancer_api.c',
-  'src/core/ext/lb_policy/grpclb/proto/grpc/lb/v0/load_balancer.pb.c',
+  'src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c',
   'third_party/nanopb/pb_common.c',
   'third_party/nanopb/pb_decode.c',
   'third_party/nanopb/pb_encode.c',
diff --git a/src/python/grpcio/grpc_version.py b/src/python/grpcio/grpc_version.py
index 873b4e2a91..0c13104d9d 100644
--- a/src/python/grpcio/grpc_version.py
+++ b/src/python/grpcio/grpc_version.py
@@ -29,4 +29,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio/grpc_version.py.template`!!!
 
-VERSION='0.14.0.dev0'
+VERSION='0.15.0.dev0'
diff --git a/src/python/grpcio/precompiled.py b/src/python/grpcio/precompiled.py
deleted file mode 100644
index b6aa7fc90e..0000000000
--- a/src/python/grpcio/precompiled.py
+++ /dev/null
@@ -1,114 +0,0 @@
-# Copyright 2015, Google Inc.
-# All rights reserved.
-#
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions are
-# met:
-#
-#     * Redistributions of source code must retain the above copyright
-# notice, this list of conditions and the following disclaimer.
-#     * Redistributions in binary form must reproduce the above
-# copyright notice, this list of conditions and the following disclaimer
-# in the documentation and/or other materials provided with the
-# distribution.
-#     * Neither the name of Google Inc. nor the names of its
-# contributors may be used to endorse or promote products derived from
-# this software without specific prior written permission.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-import os
-import platform
-import shutil
-import sys
-import sysconfig
-
-import setuptools
-
-import commands
-import grpc_version
-
-try:
-  from urllib2 import urlopen
-except ImportError:
-  from urllib.request import urlopen
-
-PYTHON_STEM = os.path.dirname(os.path.abspath(__file__))
-BINARIES_REPOSITORY = os.environ.get(
-    'GRPC_PYTHON_BINARIES_REPOSITORY',
-    'https://storage.googleapis.com/grpc-precompiled-binaries/python')
-USE_PRECOMPILED_BINARIES = bool(int(os.environ.get(
-    'GRPC_PYTHON_USE_PRECOMPILED_BINARIES', '1')))
-
-def _tagged_ext_name(base):
-  uname = platform.uname()
-  tags = (
-      grpc_version.VERSION,
-      'py{}'.format(sysconfig.get_python_version()),
-      uname[0],
-      uname[4],
-  )
-  ucs = 'ucs{}'.format(sysconfig.get_config_var('Py_UNICODE_SIZE'))
-  return '{base}-{tags}-{ucs}'.format(
-      base=base, tags='-'.join(tags), ucs=ucs)
-
-
-class BuildTaggedExt(setuptools.Command):
-
-  description = 'build the gRPC tagged extensions'
-  user_options = []
-
-  def initialize_options(self):
-    # distutils requires this override.
-    pass
-
-  def finalize_options(self):
-    # distutils requires this override.
-    pass
-
-  def run(self):
-    if 'linux' in sys.platform:
-      self.run_command('build_ext')
-      try:
-        os.makedirs('dist/')
-      except OSError:
-        pass
-      shutil.copyfile(
-          os.path.join(PYTHON_STEM, 'grpc/_cython/cygrpc.so'),
-          'dist/{}.so'.format(_tagged_ext_name('cygrpc')))
-    else:
-      sys.stderr.write('nothing to do for build_tagged_ext\n')
-
-
-def update_setup_arguments(setup_arguments):
-  if not USE_PRECOMPILED_BINARIES:
-    sys.stderr.write('not using precompiled extension')
-    return
-  url = '{}/{}.so'.format(BINARIES_REPOSITORY, _tagged_ext_name('cygrpc'))
-  target_path = os.path.join(PYTHON_STEM, 'grpc/_cython/cygrpc.so')
-  try:
-    extension = urlopen(url).read()
-  except:
-    sys.stderr.write(
-        'could not download precompiled extension: {}\n'.format(url))
-    return
-  try:
-    with open(target_path, 'w') as target:
-      target.write(extension)
-    setup_arguments['ext_modules'] = []
-  except:
-    sys.stderr.write(
-        'could not write precompiled extension to directory: {} -> {}\n'
-            .format(url, target_path))
-    return
-  setup_arguments['package_data']['grpc._cython'].append('cygrpc.so')
diff --git a/src/python/grpcio/tests/stress/client.py b/src/python/grpcio/tests/stress/client.py
index a733741b73..e2e016760c 100644
--- a/src/python/grpcio/tests/stress/client.py
+++ b/src/python/grpcio/tests/stress/client.py
@@ -117,7 +117,10 @@ def run_test(args):
   for runner in runners:
     runner.start()
   try:
-    raise exception_queue.get(block=True, timeout=args.test_duration_secs)
+    timeout_secs = args.test_duration_secs
+    if timeout_secs < 0:
+      timeout_secs = None
+    raise exception_queue.get(block=True, timeout=timeout_secs)
   except Queue.Empty:
     # No exceptions thrown, success
     pass
diff --git a/src/python/grpcio/tests/unit/_cython/_channel_test.py b/src/python/grpcio/tests/unit/_cython/_channel_test.py
index b414f8e6f6..931cd9083e 100644
--- a/src/python/grpcio/tests/unit/_cython/_channel_test.py
+++ b/src/python/grpcio/tests/unit/_cython/_channel_test.py
@@ -33,8 +33,7 @@ import unittest
 
 from grpc._cython import cygrpc
 
-# TODO(nathaniel): This should be at least one hundred. Why not one thousand?
-_PARALLELISM = 4
+from tests.unit.framework.common import test_constants
 
 
 def _channel_and_completion_queue():
@@ -61,7 +60,7 @@ def _create_loop_destroy():
 def _in_parallel(behavior, arguments):
   threads = tuple(
       threading.Thread(target=behavior, args=arguments)
-      for _ in range(_PARALLELISM))
+      for _ in range(test_constants.PARALLELISM))
   for thread in threads:
     thread.start()
   for thread in threads:
diff --git a/src/ruby/.rubocop.yml b/src/ruby/.rubocop.yml
index d13ce42655..34bb477543 100644
--- a/src/ruby/.rubocop.yml
+++ b/src/ruby/.rubocop.yml
@@ -11,10 +11,10 @@ AllCops:
     - 'pb/test/**/*'
 
 Metrics/CyclomaticComplexity:
-  Max: 8
+  Max: 9
 
 Metrics/PerceivedComplexity:
-  Max: 8
+  Max: 9
 
 Metrics/ClassLength:
   Max: 250
diff --git a/src/ruby/ext/grpc/extconf.rb b/src/ruby/ext/grpc/extconf.rb
index 07f7bb93b8..6d65db8306 100644
--- a/src/ruby/ext/grpc/extconf.rb
+++ b/src/ruby/ext/grpc/extconf.rb
@@ -78,9 +78,11 @@ output_dir = File.expand_path(RbConfig::CONFIG['topdir'])
 grpc_lib_dir = File.join(output_dir, 'libs', grpc_config)
 ENV['BUILDDIR'] = output_dir
 
-puts 'Building internal gRPC into ' + grpc_lib_dir
-system("make -j -C #{grpc_root} #{grpc_lib_dir}/libgrpc.a CONFIG=#{grpc_config}")
-exit 1 unless $? == 0
+unless windows
+  puts 'Building internal gRPC into ' + grpc_lib_dir
+  system("make -j -C #{grpc_root} #{grpc_lib_dir}/libgrpc.a CONFIG=#{grpc_config}")
+  exit 1 unless $? == 0
+end
 
 $CFLAGS << ' -I' + File.join(grpc_root, 'include')
 $LDFLAGS << ' ' + File.join(grpc_lib_dir, 'libgrpc.a') unless windows
diff --git a/src/ruby/ext/grpc/rb_byte_buffer.c b/src/ruby/ext/grpc/rb_byte_buffer.c
index cba910d832..1172691116 100644
--- a/src/ruby/ext/grpc/rb_byte_buffer.c
+++ b/src/ruby/ext/grpc/rb_byte_buffer.c
@@ -32,11 +32,10 @@
  */
 
 #include <ruby/ruby.h>
+
 #include "rb_grpc_imports.generated.h"
 #include "rb_byte_buffer.h"
 
-#include <ruby/ruby.h>
-
 #include <grpc/grpc.h>
 #include <grpc/byte_buffer_reader.h>
 #include <grpc/support/slice.h>
diff --git a/src/ruby/ext/grpc/rb_call.c b/src/ruby/ext/grpc/rb_call.c
index 48c49a21e9..1b06273af9 100644
--- a/src/ruby/ext/grpc/rb_call.c
+++ b/src/ruby/ext/grpc/rb_call.c
@@ -32,11 +32,10 @@
  */
 
 #include <ruby/ruby.h>
+
 #include "rb_grpc_imports.generated.h"
 #include "rb_call.h"
 
-#include <ruby/ruby.h>
-
 #include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
 
diff --git a/src/ruby/ext/grpc/rb_call_credentials.c b/src/ruby/ext/grpc/rb_call_credentials.c
index 38bf1f7710..79ca5b32ce 100644
--- a/src/ruby/ext/grpc/rb_call_credentials.c
+++ b/src/ruby/ext/grpc/rb_call_credentials.c
@@ -32,10 +32,10 @@
  */
 
 #include <ruby/ruby.h>
+
 #include "rb_grpc_imports.generated.h"
 #include "rb_call_credentials.h"
 
-#include <ruby/ruby.h>
 #include <ruby/thread.h>
 
 #include <grpc/grpc.h>
@@ -86,11 +86,11 @@ static VALUE grpc_rb_call_credentials_callback_rescue(VALUE args,
       rb_funcall(exception_object, rb_intern("backtrace"), 0),
       rb_intern("join"),
       1, rb_str_new2("\n\tfrom "));
-  VALUE exception_info = rb_funcall(exception_object, rb_intern("to_s"), 0);
+  VALUE rb_exception_info = rb_funcall(exception_object, rb_intern("to_s"), 0);
   const char *exception_classname = rb_obj_classname(exception_object);
   (void)args;
   gpr_log(GPR_INFO, "Call credentials callback failed: %s: %s\n%s",
-          exception_classname, StringValueCStr(exception_info),
+          exception_classname, StringValueCStr(rb_exception_info),
           StringValueCStr(backtrace));
   rb_hash_aset(result, rb_str_new2("metadata"), Qnil);
   /* Currently only gives the exception class name. It should be possible get
diff --git a/src/ruby/ext/grpc/rb_channel.c b/src/ruby/ext/grpc/rb_channel.c
index 984afad107..013321ffc8 100644
--- a/src/ruby/ext/grpc/rb_channel.c
+++ b/src/ruby/ext/grpc/rb_channel.c
@@ -32,11 +32,10 @@
  */
 
 #include <ruby/ruby.h>
+
 #include "rb_grpc_imports.generated.h"
 #include "rb_channel.h"
 
-#include <ruby/ruby.h>
-
 #include <grpc/grpc.h>
 #include <grpc/grpc_security.h>
 #include <grpc/support/alloc.h>
diff --git a/src/ruby/ext/grpc/rb_channel_args.c b/src/ruby/ext/grpc/rb_channel_args.c
index 2ffb8f41da..87c0e0a705 100644
--- a/src/ruby/ext/grpc/rb_channel_args.c
+++ b/src/ruby/ext/grpc/rb_channel_args.c
@@ -32,11 +32,10 @@
  */
 
 #include <ruby/ruby.h>
+
 #include "rb_grpc_imports.generated.h"
 #include "rb_channel_args.h"
 
-#include <ruby/ruby.h>
-
 #include <grpc/grpc.h>
 
 #include "rb_grpc.h"
diff --git a/src/ruby/ext/grpc/rb_channel_credentials.c b/src/ruby/ext/grpc/rb_channel_credentials.c
index 09bd3093a9..cbb23885aa 100644
--- a/src/ruby/ext/grpc/rb_channel_credentials.c
+++ b/src/ruby/ext/grpc/rb_channel_credentials.c
@@ -31,14 +31,13 @@
  *
  */
 
+#include <ruby/ruby.h>
+
 #include <string.h>
 
-#include <ruby/ruby.h>
 #include "rb_grpc_imports.generated.h"
 #include "rb_channel_credentials.h"
 
-#include <ruby/ruby.h>
-
 #include <grpc/grpc.h>
 #include <grpc/grpc_security.h>
 #include <grpc/support/alloc.h>
diff --git a/src/ruby/ext/grpc/rb_completion_queue.c b/src/ruby/ext/grpc/rb_completion_queue.c
index 2a2eee190c..4bb615f8be 100644
--- a/src/ruby/ext/grpc/rb_completion_queue.c
+++ b/src/ruby/ext/grpc/rb_completion_queue.c
@@ -32,10 +32,10 @@
  */
 
 #include <ruby/ruby.h>
+
 #include "rb_grpc_imports.generated.h"
 #include "rb_completion_queue.h"
 
-#include <ruby/ruby.h>
 #include <ruby/thread.h>
 
 #include <grpc/grpc.h>
diff --git a/src/ruby/ext/grpc/rb_event_thread.c b/src/ruby/ext/grpc/rb_event_thread.c
index 2649a1087f..9e85bbcfbf 100644
--- a/src/ruby/ext/grpc/rb_event_thread.c
+++ b/src/ruby/ext/grpc/rb_event_thread.c
@@ -32,12 +32,12 @@
  */
 
 #include <ruby/ruby.h>
+
 #include "rb_grpc_imports.generated.h"
 #include "rb_event_thread.h"
 
 #include <stdbool.h>
 
-#include <ruby/ruby.h>
 #include <ruby/thread.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/sync.h>
diff --git a/src/ruby/ext/grpc/rb_grpc.c b/src/ruby/ext/grpc/rb_grpc.c
index acb47b0055..5277148fc9 100644
--- a/src/ruby/ext/grpc/rb_grpc.c
+++ b/src/ruby/ext/grpc/rb_grpc.c
@@ -32,11 +32,11 @@
  */
 
 #include <ruby/ruby.h>
+
 #include "rb_grpc_imports.generated.h"
 #include "rb_grpc.h"
 
 #include <math.h>
-#include <ruby/ruby.h>
 #include <ruby/vm.h>
 #include <sys/time.h>
 
@@ -50,6 +50,7 @@
 #include "rb_loader.h"
 #include "rb_server.h"
 #include "rb_server_credentials.h"
+#include "rb_signal.h"
 
 static VALUE grpc_rb_cTimeVal = Qnil;
 
@@ -332,6 +333,7 @@ void Init_grpc_c() {
   Init_grpc_channel_credentials();
   Init_grpc_server();
   Init_grpc_server_credentials();
+  Init_grpc_signals();
   Init_grpc_status_codes();
   Init_grpc_time_consts();
 }
diff --git a/src/ruby/ext/grpc/rb_server.c b/src/ruby/ext/grpc/rb_server.c
index 96e60c6776..2b3acaaf59 100644
--- a/src/ruby/ext/grpc/rb_server.c
+++ b/src/ruby/ext/grpc/rb_server.c
@@ -32,11 +32,10 @@
  */
 
 #include <ruby/ruby.h>
+
 #include "rb_grpc_imports.generated.h"
 #include "rb_server.h"
 
-#include <ruby/ruby.h>
-
 #include <grpc/grpc.h>
 #include <grpc/grpc_security.h>
 #include "rb_call.h"
diff --git a/src/ruby/ext/grpc/rb_server_credentials.c b/src/ruby/ext/grpc/rb_server_credentials.c
index b2d7280a30..3b0fb6c910 100644
--- a/src/ruby/ext/grpc/rb_server_credentials.c
+++ b/src/ruby/ext/grpc/rb_server_credentials.c
@@ -32,11 +32,10 @@
  */
 
 #include <ruby/ruby.h>
+
 #include "rb_grpc_imports.generated.h"
 #include "rb_server_credentials.h"
 
-#include <ruby/ruby.h>
-
 #include <grpc/grpc.h>
 #include <grpc/grpc_security.h>
 
diff --git a/src/ruby/ext/grpc/rb_signal.c b/src/ruby/ext/grpc/rb_signal.c
new file mode 100644
index 0000000000..a9e512374b
--- /dev/null
+++ b/src/ruby/ext/grpc/rb_signal.c
@@ -0,0 +1,70 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <ruby/ruby.h>
+#include <signal.h>
+#include <stdbool.h>
+
+#include <grpc/support/log.h>
+
+#include "rb_grpc.h"
+
+static void (*old_sigint_handler)(int);
+static void (*old_sigterm_handler)(int);
+
+static volatile bool signal_received = false;
+
+/* This has to be handled at the C level instead of Ruby, because Ruby signal
+ * handlers are constrained to run in the main interpreter thread. If that main
+ * thread is blocked on grpc_completion_queue_pluck, the signal handlers will
+ * never run */
+static void handle_signal(int signum) {
+  signal_received = true;
+  if (signum == SIGINT) {
+    old_sigint_handler(signum);
+  } else if (signum == SIGTERM) {
+    old_sigterm_handler(signum);
+  }
+}
+
+static VALUE grpc_rb_signal_received(VALUE self) {
+  (void)self;
+  return signal_received ? Qtrue : Qfalse;
+}
+
+void Init_grpc_signals() {
+  old_sigint_handler = signal(SIGINT, handle_signal);
+  old_sigterm_handler = signal(SIGTERM, handle_signal);
+  rb_define_singleton_method(grpc_rb_mGrpcCore, "signal_received?",
+                             grpc_rb_signal_received, 0);
+}
diff --git a/src/ruby/ext/grpc/rb_signal.h b/src/ruby/ext/grpc/rb_signal.h
new file mode 100644
index 0000000000..07e49c0a8b
--- /dev/null
+++ b/src/ruby/ext/grpc/rb_signal.h
@@ -0,0 +1,39 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_RB_SIGNAL_H_
+#define GRPC_RB_SIGNAL_H_
+
+void Init_grpc_signals();
+
+#endif  /* GRPC_RB_SIGNAL_H_ */
diff --git a/src/ruby/lib/grpc.rb b/src/ruby/lib/grpc.rb
index 79fa705b1c..7c9aae30e9 100644
--- a/src/ruby/lib/grpc.rb
+++ b/src/ruby/lib/grpc.rb
@@ -33,6 +33,7 @@ require_relative 'grpc/errors'
 require_relative 'grpc/grpc'
 require_relative 'grpc/logconfig'
 require_relative 'grpc/notifier'
+require_relative 'grpc/signals'
 require_relative 'grpc/version'
 require_relative 'grpc/core/time_consts'
 require_relative 'grpc/generic/active_call'
@@ -47,3 +48,5 @@ begin
 ensure
   file.close
 end
+
+GRPC::Signals.wait_for_signals
diff --git a/src/ruby/lib/grpc/generic/active_call.rb b/src/ruby/lib/grpc/generic/active_call.rb
index ecf3cc3293..fd20a86144 100644
--- a/src/ruby/lib/grpc/generic/active_call.rb
+++ b/src/ruby/lib/grpc/generic/active_call.rb
@@ -28,7 +28,9 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 require 'forwardable'
+require 'weakref'
 require_relative 'bidi_call'
+require_relative '../signals'
 
 class Struct
   # BatchResult is the struct returned by calls to call#start_batch.
@@ -121,6 +123,10 @@ module GRPC
       @unmarshal = unmarshal
       @metadata_tag = metadata_tag
       @op_notifier = nil
+      weak_self = WeakRef.new(self)
+      remove_handler = GRPC::Signals.register_handler(&weak_self
+                                                        .method(:cancel))
+      ObjectSpace.define_finalizer(self, remove_handler)
     end
 
     # output_metadata are provides access to hash that can be used to
diff --git a/src/ruby/lib/grpc/generic/rpc_server.rb b/src/ruby/lib/grpc/generic/rpc_server.rb
index 7f3a38a9f4..238aaa9656 100644
--- a/src/ruby/lib/grpc/generic/rpc_server.rb
+++ b/src/ruby/lib/grpc/generic/rpc_server.rb
@@ -28,46 +28,13 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 require_relative '../grpc'
+require_relative '../signals'
 require_relative 'active_call'
 require_relative 'service'
 require 'thread'
 
-# A global that contains signals the gRPC servers should respond to.
-$grpc_signals = []
-
 # GRPC contains the General RPC module.
 module GRPC
-  # Handles the signals in $grpc_signals.
-  #
-  # @return false if the server should exit, true if not.
-  def handle_signals
-    loop do
-      sig = $grpc_signals.shift
-      case sig
-      when 'INT'
-        return false
-      when 'TERM'
-        return false
-      when nil
-        return true
-      end
-    end
-    true
-  end
-  module_function :handle_signals
-
-  # Sets up a signal handler that adds signals to the signal handling global.
-  #
-  # Signal handlers should do as little as humanly possible.
-  # Here, they just add themselves to $grpc_signals
-  #
-  # RpcServer (and later other parts of gRPC) monitors the signals
-  # $grpc_signals in its own non-signal context.
-  def trap_signals
-    %w(INT TERM).each { |sig| trap(sig) { $grpc_signals << sig } }
-  end
-  module_function :trap_signals
-
   # Pool is a simple thread pool.
   class Pool
     # Default keep alive period is 1s
@@ -328,25 +295,6 @@ module GRPC
       end
     end
 
-    # Runs the server in its own thread, then waits for signal INT or TERM on
-    # the current thread to terminate it.
-    def run_till_terminated
-      GRPC.trap_signals
-      stopped = false
-      t = Thread.new do
-        run
-        stopped = true
-      end
-      wait_till_running
-      loop do
-        sleep SIGNAL_CHECK_PERIOD
-        break if stopped
-        break unless GRPC.handle_signals
-      end
-      stop
-      t.join
-    end
-
     # handle registration of classes
     #
     # service is either a class that includes GRPC::GenericService and whose
@@ -405,9 +353,14 @@ module GRPC
         transition_running_state(:running)
         @run_cond.broadcast
       end
+      remove_signal_handler = GRPC::Signals.register_handler { stop }
       loop_handle_server_calls
+      # Remove signal handler when server stops
+      remove_signal_handler.call
     end
 
+    alias_method :run_till_terminated, :run
+
     # Sends RESOURCE_EXHAUSTED if there are too many unprocessed jobs
     def available?(an_rpc)
       jobs_count, max = @pool.jobs_waiting, @max_waiting_requests
@@ -416,7 +369,7 @@ module GRPC
       GRPC.logger.warn("NOT AVAILABLE: too many jobs_waiting: #{an_rpc}")
       noop = proc { |x| x }
       c = ActiveCall.new(an_rpc.call, @cq, noop, noop, an_rpc.deadline)
-      c.send_status(StatusCodes::RESOURCE_EXHAUSTED, '')
+      c.send_status(GRPC::Core::StatusCodes::RESOURCE_EXHAUSTED, '')
       nil
     end
 
@@ -427,7 +380,7 @@ module GRPC
       GRPC.logger.warn("UNIMPLEMENTED: #{an_rpc}")
       noop = proc { |x| x }
       c = ActiveCall.new(an_rpc.call, @cq, noop, noop, an_rpc.deadline)
-      c.send_status(StatusCodes::UNIMPLEMENTED, '')
+      c.send_status(GRPC::Core::StatusCodes::UNIMPLEMENTED, '')
       nil
     end
 
@@ -443,7 +396,12 @@ module GRPC
           unless active_call.nil?
             @pool.schedule(active_call) do |ac|
               c, mth = ac
-              rpc_descs[mth].run_server_method(c, rpc_handlers[mth])
+              begin
+                rpc_descs[mth].run_server_method(c, rpc_handlers[mth])
+              rescue StandardError
+                c.send_status(GRPC::Core::StatusCodes::INTERNAL,
+                              'Server handler failed')
+              end
             end
           end
         rescue Core::CallError, RuntimeError => e
@@ -500,10 +458,8 @@ module GRPC
       unless cls.include?(GenericService)
         fail "#{cls} must 'include GenericService'"
       end
-      if cls.rpc_descs.size.zero?
-        fail "#{cls} should specify some rpc descriptions"
-      end
-      cls.assert_rpc_descs_have_methods
+      fail "#{cls} should specify some rpc descriptions" if
+        cls.rpc_descs.size.zero?
     end
 
     # This should be called while holding @run_mutex
diff --git a/src/ruby/lib/grpc/generic/service.rb b/src/ruby/lib/grpc/generic/service.rb
index 8e940b5b13..0a166e823e 100644
--- a/src/ruby/lib/grpc/generic/service.rb
+++ b/src/ruby/lib/grpc/generic/service.rb
@@ -110,6 +110,9 @@ module GRPC
         rpc_descs[name] = RpcDesc.new(name, input, output,
                                       marshal_class_method,
                                       unmarshal_class_method)
+        define_method(name) do
+          fail GRPC::BadStatus, GRPC::Core::StatusCodes::UNIMPLEMENTED
+        end
       end
 
       def inherited(subclass)
@@ -199,19 +202,6 @@ module GRPC
           end
         end
       end
-
-      # Asserts that the appropriate methods are defined for each added rpc
-      # spec. Is intended to aid verifying that server classes are correctly
-      # implemented.
-      def assert_rpc_descs_have_methods
-        rpc_descs.each_pair do |m, spec|
-          mth_name = GenericService.underscore(m.to_s).to_sym
-          unless instance_methods.include?(mth_name)
-            fail "#{self} does not provide instance method '#{mth_name}'"
-          end
-          spec.assert_arity_matches(instance_method(mth_name))
-        end
-      end
     end
 
     def self.included(o)
diff --git a/src/ruby/lib/grpc/signals.rb b/src/ruby/lib/grpc/signals.rb
new file mode 100644
index 0000000000..2ab85c8bb1
--- /dev/null
+++ b/src/ruby/lib/grpc/signals.rb
@@ -0,0 +1,69 @@
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+require 'thread'
+require_relative 'grpc'
+
+# GRPC contains the General RPC module.
+module GRPC
+  # Signals contains gRPC functions related to signal handling
+  module Signals
+    @interpreter_exiting = false
+    @signal_handlers = []
+    @handlers_mutex = Mutex.new
+
+    def register_handler(&handler)
+      @handlers_mutex.synchronize do
+        @signal_handlers.push(handler)
+        handler.call if @exit_signal_received
+      end
+      # Returns a function to remove the handler
+      lambda do
+        @handlers_mutex.synchronize { @signal_handlers.delete(handler) }
+      end
+    end
+    module_function :register_handler
+
+    def wait_for_signals
+      t = Thread.new do
+        sleep 0.1 until GRPC::Core.signal_received? || @interpreter_exiting
+        unless @interpreter_exiting
+          @handlers_mutex.synchronize do
+            @signal_handlers.each(&:call)
+          end
+        end
+      end
+      at_exit do
+        @interpreter_exiting = true
+        t.join
+      end
+    end
+    module_function :wait_for_signals
+  end
+end
diff --git a/src/ruby/lib/grpc/version.rb b/src/ruby/lib/grpc/version.rb
index 67c6a5d5a1..01c8c5ac8f 100644
--- a/src/ruby/lib/grpc/version.rb
+++ b/src/ruby/lib/grpc/version.rb
@@ -29,5 +29,5 @@
 
 # GRPC contains the General RPC module.
 module GRPC
-  VERSION = '0.14.0.dev'
+  VERSION = '0.15.0.dev'
 end
diff --git a/src/ruby/spec/generic/rpc_server_spec.rb b/src/ruby/spec/generic/rpc_server_spec.rb
index e688057cb1..2a42736237 100644
--- a/src/ruby/spec/generic/rpc_server_spec.rb
+++ b/src/ruby/spec/generic/rpc_server_spec.rb
@@ -308,10 +308,6 @@ describe GRPC::RpcServer do
       expect { @srv.handle(EmptyService) }.to raise_error
     end
 
-    it 'raises if the service does not define its rpc methods' do
-      expect { @srv.handle(NoRpcImplementation) }.to raise_error
-    end
-
     it 'raises if a handler method is already registered' do
       @srv.handle(EchoService)
       expect { r.handle(EchoService) }.to raise_error
@@ -349,6 +345,25 @@ describe GRPC::RpcServer do
         t.join
       end
 
+      it 'should return UNIMPLEMENTED on unimplemented methods', server: true do
+        @srv.handle(NoRpcImplementation)
+        t = Thread.new { @srv.run }
+        @srv.wait_till_running
+        req = EchoMsg.new
+        blk = proc do
+          cq = GRPC::Core::CompletionQueue.new
+          stub = GRPC::ClientStub.new(@host, cq, :this_channel_is_insecure,
+                                      **client_opts)
+          stub.request_response('/an_rpc', req, marshal, unmarshal)
+        end
+        expect(&blk).to raise_error do |error|
+          expect(error).to be_a(GRPC::BadStatus)
+          expect(error.code).to be(GRPC::Core::StatusCodes::UNIMPLEMENTED)
+        end
+        @srv.stop
+        t.join
+      end
+
       it 'should handle multiple sequential requests', server: true do
         @srv.handle(EchoService)
         t = Thread.new { @srv.run }
diff --git a/src/ruby/spec/generic/service_spec.rb b/src/ruby/spec/generic/service_spec.rb
index 5e7b6c7aba..76034e4f74 100644
--- a/src/ruby/spec/generic/service_spec.rb
+++ b/src/ruby/spec/generic/service_spec.rb
@@ -273,73 +273,4 @@ describe GenericService do
       end
     end
   end
-
-  describe '#assert_rpc_descs_have_methods' do
-    it 'fails if there is no instance method for an rpc descriptor' do
-      c1 = Class.new do
-        include GenericService
-        rpc :AnRpc, GoodMsg, GoodMsg
-      end
-      expect { c1.assert_rpc_descs_have_methods }.to raise_error
-
-      c2 = Class.new do
-        include GenericService
-        rpc :AnRpc, GoodMsg, GoodMsg
-        rpc :AnotherRpc, GoodMsg, GoodMsg
-
-        def an_rpc
-        end
-      end
-      expect { c2.assert_rpc_descs_have_methods }.to raise_error
-    end
-
-    it 'passes if there are corresponding methods for each descriptor' do
-      c = Class.new do
-        include GenericService
-        rpc :AnRpc, GoodMsg, GoodMsg
-        rpc :AServerStreamer, GoodMsg, stream(GoodMsg)
-        rpc :AClientStreamer, stream(GoodMsg), GoodMsg
-        rpc :ABidiStreamer, stream(GoodMsg), stream(GoodMsg)
-
-        def an_rpc(_req, _call)
-        end
-
-        def a_server_streamer(_req, _call)
-        end
-
-        def a_client_streamer(_call)
-        end
-
-        def a_bidi_streamer(_call)
-        end
-      end
-      expect { c.assert_rpc_descs_have_methods }.to_not raise_error
-    end
-
-    it 'passes for subclasses of that include GenericService' do
-      base = Class.new do
-        include GenericService
-        rpc :AnRpc, GoodMsg, GoodMsg
-
-        def an_rpc(_req, _call)
-        end
-      end
-      c = Class.new(base)
-      expect { c.assert_rpc_descs_have_methods }.to_not raise_error
-      expect(c.include?(GenericService)).to be(true)
-    end
-
-    it 'passes if subclasses define the rpc methods' do
-      base = Class.new do
-        include GenericService
-        rpc :AnRpc, GoodMsg, GoodMsg
-      end
-      c = Class.new(base) do
-        def an_rpc(_req, _call)
-        end
-      end
-      expect { c.assert_rpc_descs_have_methods }.to_not raise_error
-      expect(c.include?(GenericService)).to be(true)
-    end
-  end
 end
diff --git a/src/ruby/tools/bin/protoc.rb b/src/ruby/tools/bin/grpc_tools_ruby_protoc.rb
index 3a2a5b8dc9..3a2a5b8dc9 100755
--- a/src/ruby/tools/bin/protoc.rb
+++ b/src/ruby/tools/bin/grpc_tools_ruby_protoc.rb
diff --git a/src/ruby/tools/bin/protoc_grpc_ruby_plugin.rb b/src/ruby/tools/bin/grpc_tools_ruby_protoc_plugin.rb
index 4b296dedc7..4b296dedc7 100755
--- a/src/ruby/tools/bin/protoc_grpc_ruby_plugin.rb
+++ b/src/ruby/tools/bin/grpc_tools_ruby_protoc_plugin.rb
diff --git a/src/ruby/tools/version.rb b/src/ruby/tools/version.rb
index 12ad21b80e..dca7fd7e72 100644
--- a/src/ruby/tools/version.rb
+++ b/src/ruby/tools/version.rb
@@ -29,6 +29,6 @@
 
 module GRPC
   module Tools
-    VERSION = '0.14.0.dev'
+    VERSION = '0.15.0.dev'
   end
 end