merge with head

36 files changed, 1067 insertions, 107 deletions

diff --git a/test/core/client_config/lb_policies_test.c b/test/core/client_config/lb_policies_test.c
index 0218b8f07f..5aa8140e08 100644
--- a/test/core/client_config/lb_policies_test.c
+++ b/test/core/client_config/lb_policies_test.c
@@ -269,8 +269,8 @@ int *perform_request(servers_fixture *f, grpc_channel *client,
     memset(s_valid, 0, f->num_servers * sizeof(int));
 
     c = grpc_channel_create_call(client, NULL, GRPC_PROPAGATE_DEFAULTS, f->cq,
-                                 "/foo", "foo.test.google.fr", gpr_inf_future(GPR_CLOCK_REALTIME),
-                                 NULL);
+                                 "/foo", "foo.test.google.fr",
+                                 gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
     GPR_ASSERT(c);
     completed_client = 0;
 
diff --git a/test/core/end2end/fixtures/proxy.c b/test/core/end2end/fixtures/proxy.c
index 1090ad667d..434e75dd15 100644
--- a/test/core/end2end/fixtures/proxy.c
+++ b/test/core/end2end/fixtures/proxy.c
@@ -146,7 +146,6 @@ void grpc_end2end_proxy_destroy(grpc_end2end_proxy *proxy) {
 }
 
 static void unrefpc(proxy_call *pc, const char *reason) {
-  gpr_log(GPR_DEBUG, "PROXY UNREF %s", reason);
   if (gpr_unref(&pc->refs)) {
     grpc_call_destroy(pc->c2p);
     grpc_call_destroy(pc->p2s);
@@ -158,10 +157,7 @@ static void unrefpc(proxy_call *pc, const char *reason) {
   }
 }
 
-static void refpc(proxy_call *pc, const char *reason) {
-  gpr_log(GPR_DEBUG, "PROXY   REF %s", reason);
-  gpr_ref(&pc->refs);
-}
+static void refpc(proxy_call *pc, const char *reason) { gpr_ref(&pc->refs); }
 
 static void on_c2p_sent_initial_metadata(void *arg, int success) {
   proxy_call *pc = arg;
diff --git a/test/core/end2end/gen_build_yaml.py b/test/core/end2end/gen_build_yaml.py
index 38d3b2218a..33687b8cd4 100755
--- a/test/core/end2end/gen_build_yaml.py
+++ b/test/core/end2end/gen_build_yaml.py
@@ -37,8 +37,8 @@ import collections
 import hashlib
 
 
-FixtureOptions = collections.namedtuple('FixtureOptions', 'fullstack includes_proxy dns_resolver secure platforms ci_mac')
-default_unsecure_fixture_options = FixtureOptions(True, False, True, False, ['windows', 'linux', 'mac', 'posix'], True)
+FixtureOptions = collections.namedtuple('FixtureOptions', 'fullstack includes_proxy dns_resolver secure platforms ci_mac tracing')
+default_unsecure_fixture_options = FixtureOptions(True, False, True, False, ['windows', 'linux', 'mac', 'posix'], True, False)
 socketpair_unsecure_fixture_options = default_unsecure_fixture_options._replace(fullstack=False, dns_resolver=False)
 default_secure_fixture_options = default_unsecure_fixture_options._replace(secure=True)
 uds_fixture_options = default_unsecure_fixture_options._replace(dns_resolver=False, platforms=['linux', 'mac', 'posix'])
@@ -54,7 +54,7 @@ END2END_FIXTURES = {
     'h2_proxy': default_unsecure_fixture_options._replace(includes_proxy=True, ci_mac=False),
     'h2_sockpair_1byte': socketpair_unsecure_fixture_options._replace(ci_mac=False),
     'h2_sockpair': socketpair_unsecure_fixture_options._replace(ci_mac=False),
-    'h2_sockpair+trace': socketpair_unsecure_fixture_options,
+    'h2_sockpair+trace': socketpair_unsecure_fixture_options._replace(tracing=True),
     'h2_ssl': default_secure_fixture_options,
     'h2_ssl+poll': default_secure_fixture_options._replace(platforms=['linux']),
     'h2_ssl_proxy': default_secure_fixture_options._replace(includes_proxy=True, ci_mac=False),
@@ -63,8 +63,8 @@ END2END_FIXTURES = {
     'h2_uds': uds_fixture_options,
 }
 
-TestOptions = collections.namedtuple('TestOptions', 'needs_fullstack needs_dns proxyable flaky secure')
-default_test_options = TestOptions(False, False, True, False, False)
+TestOptions = collections.namedtuple('TestOptions', 'needs_fullstack needs_dns proxyable flaky secure traceable')
+default_test_options = TestOptions(False, False, True, False, False, True)
 connectivity_test_options = default_test_options._replace(needs_fullstack=True)
 
 # maps test names to options
@@ -85,6 +85,7 @@ END2END_TESTS = {
     'disappearing_server': connectivity_test_options,
     'empty_batch': default_test_options,
     'graceful_server_shutdown': default_test_options,
+    'hpack_size': default_test_options._replace(proxyable=False, traceable=False),
     'high_initial_seqno': default_test_options,
     'invoke_large_request': default_test_options,
     'large_metadata': default_test_options,
@@ -117,6 +118,9 @@ def compatible(f, t):
   if not END2END_TESTS[t].proxyable:
     if END2END_FIXTURES[f].includes_proxy:
       return False
+  if not END2END_TESTS[t].traceable:
+    if END2END_FIXTURES[f].tracing:
+      return False
   return True
 
 
diff --git a/test/core/end2end/tests/cancel_with_status.c b/test/core/end2end/tests/cancel_with_status.c
index eecfa83fa4..2005e5f881 100644
--- a/test/core/end2end/tests/cancel_with_status.c
+++ b/test/core/end2end/tests/cancel_with_status.c
@@ -166,7 +166,8 @@ static void simple_request_body(grpc_end2end_test_fixture f, size_t num_ops) {
   cq_verifier_destroy(cqv);
 }
 
-static void test_invoke_simple_request(grpc_end2end_test_config config, size_t num_ops) {
+static void test_invoke_simple_request(grpc_end2end_test_config config,
+                                       size_t num_ops) {
   grpc_end2end_test_fixture f;
 
   f = begin_test(config, "test_invoke_simple_request", NULL, NULL);
diff --git a/test/core/end2end/tests/hpack_size.c b/test/core/end2end/tests/hpack_size.c
new file mode 100644
index 0000000000..297ea8d542
--- /dev/null
+++ b/test/core/end2end/tests/hpack_size.c
@@ -0,0 +1,446 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include "test/core/end2end/end2end_tests.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include <grpc/byte_buffer.h>
+#include <grpc/grpc.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/time.h>
+#include <grpc/support/useful.h>
+
+#include "src/core/support/string.h"
+#include "test/core/end2end/cq_verifier.h"
+
+static void *tag(gpr_intptr t) { return (void *)t; }
+
+const char *hobbits[][2] = {{"Adaldrida", "Brandybuck"},
+                            {"Adamanta", "Took"},
+                            {"Adalgrim", "Took"},
+                            {"Adelard", "Took"},
+                            {"Amaranth", "Brandybuck"},
+                            {"Andwise", "Roper"},
+                            {"Angelica", "Baggins"},
+                            {"Asphodel", "Burrows"},
+                            {"Balbo", "Baggins"},
+                            {"Bandobras", "Took"},
+                            {"Belba", "Bolger"},
+                            {"Bell", "Gamgee"},
+                            {"Belladonna", "Baggins"},
+                            {"Berylla", "Baggins"},
+                            {"Bilbo", "Baggins"},
+                            {"Bilbo", "Gardner"},
+                            {"Bill", "Butcher"},
+                            {"Bingo", "Baggins"},
+                            {"Bodo", "Proudfoot"},
+                            {"Bowman", "Cotton"},
+                            {"Bungo", "Baggins"},
+                            {"Camellia", "Sackville"},
+                            {"Carl", "Cotton"},
+                            {"Celandine", "Brandybuck"},
+                            {"Chica", "Baggins"},
+                            {"Daddy", "Twofoot"},
+                            {"Daisy", "Boffin"},
+                            {"Diamond", "Took"},
+                            {"Dinodas", "Brandybuck"},
+                            {"Doderic", "Brandybuck"},
+                            {"Dodinas", "Brandybuck"},
+                            {"Donnamira", "Boffin"},
+                            {"Dora", "Baggins"},
+                            {"Drogo", "Baggins"},
+                            {"Dudo", "Baggins"},
+                            {"Eglantine", "Took"},
+                            {"Elanor", "Fairbairn"},
+                            {"Elfstan", "Fairbairn"},
+                            {"Esmeralda", "Brandybuck"},
+                            {"Estella", "Brandybuck"},
+                            {"Everard", "Took"},
+                            {"Falco", "Chubb-Baggins"},
+                            {"Faramir", "Took"},
+                            {"Farmer", "Maggot"},
+                            {"Fastolph", "Bolger"},
+                            {"Ferdibrand", "Took"},
+                            {"Ferdinand", "Took"},
+                            {"Ferumbras", "Took"},
+                            {"Ferumbras", "Took"},
+                            {"Filibert", "Bolger"},
+                            {"Firiel", "Fairbairn"},
+                            {"Flambard", "Took"},
+                            {"Folco", "Boffin"},
+                            {"Fortinbras", "Took"},
+                            {"Fortinbras", "Took"},
+                            {"Fosco", "Baggins"},
+                            {"Fredegar", "Bolger"},
+                            {"Frodo", "Baggins"},
+                            {"Frodo", "Gardner"},
+                            {"Gerontius", "Took"},
+                            {"Gilly", "Baggins"},
+                            {"Goldilocks", "Took"},
+                            {"Gorbadoc", "Brandybuck"},
+                            {"Gorbulas", "Brandybuck"},
+                            {"Gorhendad", "Brandybuck"},
+                            {"Gormadoc", "Brandybuck"},
+                            {"Griffo", "Boffin"},
+                            {"Halfast", "Gamgee"},
+                            {"Halfred", "Gamgee"},
+                            {"Halfred", "Greenhand"},
+                            {"Hanna", "Brandybuck"},
+                            {"Hamfast", "Gamgee"},
+                            {"Hamfast", "Gardner"},
+                            {"Hamson", "Gamgee"},
+                            {"Harding", "Gardner"},
+                            {"Hilda", "Brandybuck"},
+                            {"Hildibrand", "Took"},
+                            {"Hildifons", "Took"},
+                            {"Hildigard", "Took"},
+                            {"Hildigrim", "Took"},
+                            {"Hob", "Gammidge"},
+                            {"Hob", "Hayward"},
+                            {"Hobson", "Gamgee"},
+                            {"Holfast", "Gardner"},
+                            {"Holman", "Cotton"},
+                            {"Holman", "Greenhand"},
+                            {"Hugo", "Boffin"},
+                            {"Hugo", "Bracegirdle"},
+                            {"Ilberic", "Brandybuck"},
+                            {"Isembard", "Took"},
+                            {"Isembold", "Took"},
+                            {"Isengar", "Took"},
+                            {"Isengrim", "Took"},
+                            {"Isengrim", "Took"},
+                            {"Isumbras", "Took"},
+                            {"Isumbras", "Took"},
+                            {"Jolly", "Cotton"},
+                            {"Lalia", "Took"},
+                            {"Largo", "Baggins"},
+                            {"Laura", "Baggins"},
+                            {"Lily", "Goodbody"},
+                            {"Lily", "Cotton"},
+                            {"Linda", "Proudfoot"},
+                            {"Lobelia", "Sackville-Baggins"},
+                            {"Longo", "Baggins"},
+                            {"Lotho", "Sackville-Baggins"},
+                            {"Madoc", "Brandybuck"},
+                            {"Malva", "Brandybuck"},
+                            {"Marigold", "Cotton"},
+                            {"Marmadas", "Brandybuck"},
+                            {"Marmadoc", "Brandybuck"},
+                            {"Marroc", "Brandybuck"},
+                            {"May", "Gamgee"},
+                            {"Melilot", "Brandybuck"},
+                            {"Menegilda", "Brandybuck"},
+                            {"Mentha", "Brandybuck"},
+                            {"Meriadoc", "Brandybuck"},
+                            {"Merimac", "Brandybuck"},
+                            {"Merimas", "Brandybuck"},
+                            {"Merry", "Gardner"},
+                            {"Milo", "Burrows"},
+                            {"Mimosa", "Baggins"},
+                            {"Minto", "Burrows"},
+                            {"Mirabella", "Brandybuck"},
+                            {"Moro", "Burrows"},
+                            {"Mosco", "Burrows"},
+                            {"Mungo", "Baggins"},
+                            {"Myrtle", "Burrows"},
+                            {"Odo", "Proudfoot"},
+                            {"Odovacar", "Bolger"},
+                            {"Olo", "Proudfoot"},
+                            {"Orgulas", "Brandybuck"},
+                            {"Otho", "Sackville-Baggins"},
+                            {"Paladin", "Took"},
+                            {"Pansy", "Bolger"},
+                            {"Pearl", "Took"},
+                            {"Peony", "Burrows"},
+                            {"Peregrin", "Took"},
+                            {"Pervinca", "Took"},
+                            {"Pimpernel", "Took"},
+                            {"Pippin", "Gardner"},
+                            {"Polo", "Baggins"},
+                            {"Ponto", "Baggins"},
+                            {"Porto", "Baggins"},
+                            {"Posco", "Baggins"},
+                            {"Poppy", "Bolger"},
+                            {"Primrose", "Gardner"},
+                            {"Primula", "Baggins"},
+                            {"Prisca", "Bolger"},
+                            {"Reginard", "Took"},
+                            {"Robin", "Smallburrow"},
+                            {"Robin", "Gardner"},
+                            {"Rorimac", "Brandybuck"},
+                            {"Rosa", "Took"},
+                            {"Rosamunda", "Bolger"},
+                            {"Rose", "Gardner"},
+                            {"Ruby", "Baggins"},
+                            {"Ruby", "Gardner"},
+                            {"Rudigar", "Bolger"},
+                            {"Rufus", "Burrows"},
+                            {"Sadoc", "Brandybuck"},
+                            {"Salvia", "Bolger"},
+                            {"Samwise", "Gamgee"},
+                            {"Sancho", "Proudfoot"},
+                            {"Saradas", "Brandybuck"},
+                            {"Saradoc", "Brandybuck"},
+                            {"Seredic", "Brandybuck"},
+                            {"Sigismond", "Took"},
+                            {"Smeagol", "Gollum"},
+                            {"Tanta", "Baggins"},
+                            {"Ted", "Sandyman"},
+                            {"Tobold", "Hornblower"},
+                            {"Togo", "Goodbody"},
+                            {"Tolman", "Cotton"},
+                            {"Tolman", "Gardner"},
+                            {"Widow", "Rumble"},
+                            {"Wilcome", "Cotton"},
+                            {"Wilcome", "Cotton"},
+                            {"Wilibald", "Bolger"},
+                            {"Will", "Whitfoot"},
+                            {"Wiseman", "Gamwich"}};
+
+const char *dragons[] = {"Ancalagon", "Glaurung", "Scatha",
+                         "Smaug the Magnificent"};
+
+static grpc_end2end_test_fixture begin_test(grpc_end2end_test_config config,
+                                            const char *test_name,
+                                            grpc_channel_args *client_args,
+                                            grpc_channel_args *server_args) {
+  grpc_end2end_test_fixture f;
+  gpr_log(GPR_INFO, "%s/%s", test_name, config.name);
+  f = config.create_fixture(client_args, server_args);
+  config.init_client(&f, client_args);
+  config.init_server(&f, server_args);
+  return f;
+}
+
+static gpr_timespec n_seconds_time(int n) {
+  return GRPC_TIMEOUT_SECONDS_TO_DEADLINE(n);
+}
+
+static gpr_timespec five_seconds_time(void) { return n_seconds_time(5); }
+
+static void drain_cq(grpc_completion_queue *cq) {
+  grpc_event ev;
+  do {
+    ev = grpc_completion_queue_next(cq, five_seconds_time(), NULL);
+  } while (ev.type != GRPC_QUEUE_SHUTDOWN);
+}
+
+static void shutdown_server(grpc_end2end_test_fixture *f) {
+  if (!f->server) return;
+  grpc_server_shutdown_and_notify(f->server, f->cq, tag(1000));
+  GPR_ASSERT(grpc_completion_queue_pluck(
+                 f->cq, tag(1000), GRPC_TIMEOUT_SECONDS_TO_DEADLINE(5), NULL)
+                 .type == GRPC_OP_COMPLETE);
+  grpc_server_destroy(f->server);
+  f->server = NULL;
+}
+
+static void shutdown_client(grpc_end2end_test_fixture *f) {
+  if (!f->client) return;
+  grpc_channel_destroy(f->client);
+  f->client = NULL;
+}
+
+static void end_test(grpc_end2end_test_fixture *f) {
+  shutdown_server(f);
+  shutdown_client(f);
+
+  grpc_completion_queue_shutdown(f->cq);
+  drain_cq(f->cq);
+  grpc_completion_queue_destroy(f->cq);
+}
+
+static void simple_request_body(grpc_end2end_test_fixture f, size_t index) {
+  grpc_call *c;
+  grpc_call *s;
+  gpr_timespec deadline = five_seconds_time();
+  cq_verifier *cqv = cq_verifier_create(f.cq);
+  grpc_op ops[6];
+  grpc_op *op;
+  grpc_metadata_array initial_metadata_recv;
+  grpc_metadata_array trailing_metadata_recv;
+  grpc_metadata_array request_metadata_recv;
+  grpc_call_details call_details;
+  grpc_status_code status;
+  grpc_call_error error;
+  grpc_metadata extra_metadata[3];
+  char *details = NULL;
+  size_t details_capacity = 0;
+  int was_cancelled = 2;
+
+  memset(extra_metadata, 0, sizeof(extra_metadata));
+  extra_metadata[0].key = "hobbit-first-name";
+  extra_metadata[0].value = hobbits[index % GPR_ARRAY_SIZE(hobbits)][0];
+  extra_metadata[0].value_length = strlen(extra_metadata[0].value);
+  extra_metadata[1].key = "hobbit-second-name";
+  extra_metadata[1].value = hobbits[index % GPR_ARRAY_SIZE(hobbits)][1];
+  extra_metadata[1].value_length = strlen(extra_metadata[1].value);
+  extra_metadata[2].key = "dragon";
+  extra_metadata[2].value = dragons[index % GPR_ARRAY_SIZE(dragons)];
+  extra_metadata[2].value_length = strlen(extra_metadata[2].value);
+
+  c = grpc_channel_create_call(f.client, NULL, GRPC_PROPAGATE_DEFAULTS, f.cq,
+                               "/foo", "foo.test.google.fr:1234", deadline,
+                               NULL);
+  GPR_ASSERT(c);
+
+  grpc_metadata_array_init(&initial_metadata_recv);
+  grpc_metadata_array_init(&trailing_metadata_recv);
+  grpc_metadata_array_init(&request_metadata_recv);
+  grpc_call_details_init(&call_details);
+
+  op = ops;
+  op->op = GRPC_OP_SEND_INITIAL_METADATA;
+  op->data.send_initial_metadata.count = GPR_ARRAY_SIZE(extra_metadata);
+  op->data.send_initial_metadata.metadata = extra_metadata;
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  op->op = GRPC_OP_RECV_INITIAL_METADATA;
+  op->data.recv_initial_metadata = &initial_metadata_recv;
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
+  op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
+  op->data.recv_status_on_client.status = &status;
+  op->data.recv_status_on_client.status_details = &details;
+  op->data.recv_status_on_client.status_details_capacity = &details_capacity;
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  error = grpc_call_start_batch(c, ops, (size_t)(op - ops), tag(1), NULL);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  error =
+      grpc_server_request_call(f.server, &s, &call_details,
+                               &request_metadata_recv, f.cq, f.cq, tag(101));
+  GPR_ASSERT(GRPC_CALL_OK == error);
+  cq_expect_completion(cqv, tag(101), 1);
+  cq_verify(cqv);
+
+  op = ops;
+  op->op = GRPC_OP_SEND_INITIAL_METADATA;
+  op->data.send_initial_metadata.count = 0;
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
+  op->data.send_status_from_server.trailing_metadata_count = 0;
+  op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
+  op->data.send_status_from_server.status_details = "xyz";
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
+  op->data.recv_close_on_server.cancelled = &was_cancelled;
+  op->flags = 0;
+  op->reserved = NULL;
+  op++;
+  error = grpc_call_start_batch(s, ops, (size_t)(op - ops), tag(102), NULL);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  cq_expect_completion(cqv, tag(102), 1);
+  cq_expect_completion(cqv, tag(1), 1);
+  cq_verify(cqv);
+
+  GPR_ASSERT(status == GRPC_STATUS_UNIMPLEMENTED);
+  GPR_ASSERT(0 == strcmp(details, "xyz"));
+  GPR_ASSERT(0 == strcmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == strcmp(call_details.host, "foo.test.google.fr:1234"));
+  GPR_ASSERT(was_cancelled == 1);
+
+  gpr_free(details);
+  grpc_metadata_array_destroy(&initial_metadata_recv);
+  grpc_metadata_array_destroy(&trailing_metadata_recv);
+  grpc_metadata_array_destroy(&request_metadata_recv);
+  grpc_call_details_destroy(&call_details);
+
+  grpc_call_destroy(c);
+  grpc_call_destroy(s);
+
+  cq_verifier_destroy(cqv);
+}
+
+static void test_size(grpc_end2end_test_config config, int encode_size,
+                      int decode_size) {
+  size_t i;
+  grpc_end2end_test_fixture f;
+  grpc_arg server_arg;
+  grpc_channel_args server_args;
+  grpc_arg client_arg;
+  grpc_channel_args client_args;
+  char *name;
+
+  server_arg.type = GRPC_ARG_INTEGER;
+  server_arg.key = GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_DECODER;
+  server_arg.value.integer = decode_size;
+  server_args.num_args = 1;
+  server_args.args = &server_arg;
+
+  client_arg.type = GRPC_ARG_INTEGER;
+  client_arg.key = GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_ENCODER;
+  client_arg.value.integer = encode_size;
+  client_args.num_args = 1;
+  client_args.args = &client_arg;
+
+  gpr_asprintf(&name, "test_size:e=%d:d=%d", encode_size, decode_size);
+  f = begin_test(config, name, encode_size != 4096 ? &client_args : NULL,
+                 decode_size != 4096 ? &server_args : NULL);
+  for (i = 0; i < 4 * GPR_ARRAY_SIZE(hobbits); i++) {
+    simple_request_body(f, i);
+  }
+  end_test(&f);
+  config.tear_down_data(&f);
+  gpr_free(name);
+}
+
+void grpc_end2end_tests(grpc_end2end_test_config config) {
+  static const int interesting_sizes[] = {4096, 0,     100,
+                                          1000, 32768, 4 * 1024 * 1024};
+  size_t i, j;
+
+  for (i = 0; i < GPR_ARRAY_SIZE(interesting_sizes); i++) {
+    for (j = 0; j < GPR_ARRAY_SIZE(interesting_sizes); j++) {
+      test_size(config, interesting_sizes[i], interesting_sizes[j]);
+    }
+  }
+}
diff --git a/test/core/end2end/tests/negative_deadline.c b/test/core/end2end/tests/negative_deadline.c
index abcc1ba358..8fe9e7bcc5 100644
--- a/test/core/end2end/tests/negative_deadline.c
+++ b/test/core/end2end/tests/negative_deadline.c
@@ -163,7 +163,8 @@ static void simple_request_body(grpc_end2end_test_fixture f, size_t num_ops) {
   cq_verifier_destroy(cqv);
 }
 
-static void test_invoke_simple_request(grpc_end2end_test_config config, size_t num_ops) {
+static void test_invoke_simple_request(grpc_end2end_test_config config,
+                                       size_t num_ops) {
   grpc_end2end_test_fixture f;
 
   f = begin_test(config, "test_invoke_simple_request", NULL, NULL);
diff --git a/test/core/network_benchmarks/low_level_ping_pong.c b/test/core/network_benchmarks/low_level_ping_pong.c
index 7a2d894481..dd1544c27b 100644
--- a/test/core/network_benchmarks/low_level_ping_pong.c
+++ b/test/core/network_benchmarks/low_level_ping_pong.c
@@ -139,7 +139,7 @@ static int poll_read_bytes(int fd, char *buf, size_t read_size, int spin) {
       gpr_log(GPR_ERROR, "Read failed: %s", strerror(errno));
       return -1;
     }
-    bytes_read += (size_t) err2;
+    bytes_read += (size_t)err2;
   } while (bytes_read < read_size);
   return 0;
 }
@@ -174,11 +174,11 @@ static int epoll_read_bytes(struct thread_args *args, char *buf, int spin) {
     GPR_ASSERT(ev.data.fd == args->fds.read_fd);
     do {
       do {
-        err2 = read(args->fds.read_fd, buf + bytes_read,
-		    read_size - bytes_read);
+        err2 =
+            read(args->fds.read_fd, buf + bytes_read, read_size - bytes_read);
       } while (err2 < 0 && errno == EINTR);
       if (errno == EAGAIN) break;
-      bytes_read += (size_t) err2;
+      bytes_read += (size_t)err2;
       /* TODO(klempner): This should really be doing an extra call after we are
          done to ensure we see an EAGAIN */
     } while (bytes_read < read_size);
diff --git a/test/core/security/credentials_test.c b/test/core/security/credentials_test.c
index dcb35e5309..4cfef7be78 100644
--- a/test/core/security/credentials_test.c
+++ b/test/core/security/credentials_test.c
@@ -353,8 +353,8 @@ static void test_google_iam_creds(void) {
       test_google_iam_authorization_token, test_google_iam_authority_selector,
       NULL);
   grpc_call_credentials_get_request_metadata(&exec_ctx, creds, NULL,
-                                        test_service_url,
-                                        check_google_iam_metadata, creds);
+                                             test_service_url,
+                                             check_google_iam_metadata, creds);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
@@ -436,7 +436,8 @@ static void test_oauth2_google_iam_composite_creds(void) {
       test_google_iam_authorization_token, test_google_iam_authority_selector,
       NULL);
   grpc_call_credentials *composite_creds =
-      grpc_composite_call_credentials_create(oauth2_creds, google_iam_creds, NULL);
+      grpc_composite_call_credentials_create(oauth2_creds, google_iam_creds,
+                                             NULL);
   grpc_call_credentials_unref(oauth2_creds);
   grpc_call_credentials_unref(google_iam_creds);
   GPR_ASSERT(
@@ -481,7 +482,8 @@ static void test_channel_oauth2_google_iam_composite_creds(void) {
   grpc_call_credentials *oauth2_creds =
       grpc_access_token_credentials_create("blah", NULL);
   grpc_channel_credentials *channel_oauth2_creds =
-      grpc_composite_channel_credentials_create(channel_creds, oauth2_creds, NULL);
+      grpc_composite_channel_credentials_create(channel_creds, oauth2_creds,
+                                                NULL);
   grpc_call_credentials *google_iam_creds = grpc_google_iam_credentials_create(
       test_google_iam_authorization_token, test_google_iam_authority_selector,
       NULL);
diff --git a/test/core/surface/byte_buffer_reader_test.c b/test/core/surface/byte_buffer_reader_test.c
index 7f9cd6b62b..6b41698717 100644
--- a/test/core/surface/byte_buffer_reader_test.c
+++ b/test/core/surface/byte_buffer_reader_test.c
@@ -185,8 +185,8 @@ static void test_byte_buffer_from_reader(void) {
 }
 
 static void test_readall(void) {
-  char* lotsa_as[512];
-  char* lotsa_bs[1024];
+  char *lotsa_as[512];
+  char *lotsa_bs[1024];
   gpr_slice slices[2];
   grpc_byte_buffer *buffer;
   grpc_byte_buffer_reader reader;
diff --git a/test/core/transport/chttp2/hpack_parser_test.c b/test/core/transport/chttp2/hpack_parser_test.c
index 3a313375a4..c6b35fba79 100644
--- a/test/core/transport/chttp2/hpack_parser_test.c
+++ b/test/core/transport/chttp2/hpack_parser_test.c
@@ -151,7 +151,8 @@ static void test_vectors(grpc_slice_split_mode mode) {
   grpc_chttp2_hpack_parser_destroy(&parser);
 
   grpc_chttp2_hpack_parser_init(&parser, mdctx);
-  parser.table.max_bytes = 256;
+  grpc_chttp2_hptbl_set_max_bytes(&parser.table, 256);
+  grpc_chttp2_hptbl_set_current_table_size(&parser.table, 256);
   /* D.5.1 */
   test_vector(&parser, mode,
               "4803 3330 3258 0770 7269 7661 7465 611d"
@@ -184,7 +185,8 @@ static void test_vectors(grpc_slice_split_mode mode) {
   grpc_chttp2_hpack_parser_destroy(&parser);
 
   grpc_chttp2_hpack_parser_init(&parser, mdctx);
-  parser.table.max_bytes = 256;
+  grpc_chttp2_hptbl_set_max_bytes(&parser.table, 256);
+  grpc_chttp2_hptbl_set_current_table_size(&parser.table, 256);
   /* D.6.1 */
   test_vector(&parser, mode,
               "4882 6402 5885 aec3 771a 4b61 96d0 7abe"
diff --git a/test/core/transport/chttp2/hpack_table_test.c b/test/core/transport/chttp2/hpack_table_test.c
index aa3e273a6c..5eb52d6d9a 100644
--- a/test/core/transport/chttp2/hpack_table_test.c
+++ b/test/core/transport/chttp2/hpack_table_test.c
@@ -143,9 +143,12 @@ static void test_many_additions(void) {
   grpc_chttp2_hptbl_init(&tbl, mdctx);
 
   for (i = 0; i < 1000000; i++) {
+    grpc_mdelem *elem;
     gpr_asprintf(&key, "K:%d", i);
     gpr_asprintf(&value, "VALUE:%d", i);
-    grpc_chttp2_hptbl_add(&tbl, grpc_mdelem_from_strings(mdctx, key, value));
+    elem = grpc_mdelem_from_strings(mdctx, key, value);
+    GPR_ASSERT(grpc_chttp2_hptbl_add(&tbl, elem));
+    GRPC_MDELEM_UNREF(elem);
     assert_index(&tbl, 1 + GRPC_CHTTP2_LAST_STATIC_ENTRY, key, value);
     gpr_free(key);
     gpr_free(value);
@@ -173,18 +176,25 @@ static grpc_chttp2_hptbl_find_result find_simple(grpc_chttp2_hptbl *tbl,
 
 static void test_find(void) {
   grpc_chttp2_hptbl tbl;
-  int i;
+  gpr_uint32 i;
   char buffer[32];
   grpc_mdctx *mdctx;
+  grpc_mdelem *elem;
   grpc_chttp2_hptbl_find_result r;
 
   LOG_TEST("test_find");
 
   mdctx = grpc_mdctx_create();
   grpc_chttp2_hptbl_init(&tbl, mdctx);
-  grpc_chttp2_hptbl_add(&tbl, grpc_mdelem_from_strings(mdctx, "abc", "xyz"));
-  grpc_chttp2_hptbl_add(&tbl, grpc_mdelem_from_strings(mdctx, "abc", "123"));
-  grpc_chttp2_hptbl_add(&tbl, grpc_mdelem_from_strings(mdctx, "x", "1"));
+  elem = grpc_mdelem_from_strings(mdctx, "abc", "xyz");
+  GPR_ASSERT(grpc_chttp2_hptbl_add(&tbl, elem));
+  GRPC_MDELEM_UNREF(elem);
+  elem = grpc_mdelem_from_strings(mdctx, "abc", "123");
+  GPR_ASSERT(grpc_chttp2_hptbl_add(&tbl, elem));
+  GRPC_MDELEM_UNREF(elem);
+  elem = grpc_mdelem_from_strings(mdctx, "x", "1");
+  GPR_ASSERT(grpc_chttp2_hptbl_add(&tbl, elem));
+  GRPC_MDELEM_UNREF(elem);
 
   r = find_simple(&tbl, "abc", "123");
   GPR_ASSERT(r.index == 2 + GRPC_CHTTP2_LAST_STATIC_ENTRY);
@@ -233,8 +243,9 @@ static void test_find(void) {
   /* overflow the string buffer, check find still works */
   for (i = 0; i < 10000; i++) {
     gpr_ltoa(i, buffer);
-    grpc_chttp2_hptbl_add(&tbl,
-                          grpc_mdelem_from_strings(mdctx, "test", buffer));
+    elem = grpc_mdelem_from_strings(mdctx, "test", buffer);
+    GPR_ASSERT(grpc_chttp2_hptbl_add(&tbl, elem));
+    GRPC_MDELEM_UNREF(elem);
   }
 
   r = find_simple(&tbl, "abc", "123");
@@ -250,7 +261,7 @@ static void test_find(void) {
   GPR_ASSERT(r.has_value == 1);
 
   for (i = 0; i < tbl.num_ents; i++) {
-    int expect = 9999 - i;
+    gpr_uint32 expect = 9999 - i;
     gpr_ltoa(expect, buffer);
 
     r = find_simple(&tbl, "test", buffer);
diff --git a/test/core/util/test_tcp_server.c b/test/core/util/test_tcp_server.c
index 0cd9beed80..e78d830058 100644
--- a/test/core/util/test_tcp_server.c
+++ b/test/core/util/test_tcp_server.c
@@ -57,6 +57,7 @@ void test_tcp_server_init(test_tcp_server *server,
 
 void test_tcp_server_start(test_tcp_server *server, int port) {
   struct sockaddr_in addr;
+  grpc_tcp_listener *listener;
   int port_added;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
 
@@ -65,8 +66,8 @@ void test_tcp_server_start(test_tcp_server *server, int port) {
   memset(&addr.sin_addr, 0, sizeof(addr.sin_addr));
 
   server->tcp_server = grpc_tcp_server_create();
-  port_added =
-      grpc_tcp_server_add_port(server->tcp_server, &addr, sizeof(addr));
+  listener = grpc_tcp_server_add_port(server->tcp_server, &addr, sizeof(addr));
+  port_added = grpc_tcp_listener_get_port(listener);
   GPR_ASSERT(port_added == port);
 
   grpc_tcp_server_start(&exec_ctx, server->tcp_server, server->pollsets, 1,
diff --git a/test/cpp/interop/metrics_client.cc b/test/cpp/interop/metrics_client.cc
new file mode 100644
index 0000000000..1bd2a2fd78
--- /dev/null
+++ b/test/cpp/interop/metrics_client.cc
@@ -0,0 +1,103 @@
+/*
+ *
+ * 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.
+ *is % allowed in string
+ */
+
+#include <memory>
+#include <string>
+
+#include <gflags/gflags.h>
+#include <grpc++/grpc++.h>
+
+#include "test/cpp/util/metrics_server.h"
+#include "test/cpp/util/test_config.h"
+#include "test/proto/metrics.grpc.pb.h"
+#include "test/proto/metrics.pb.h"
+
+DEFINE_string(metrics_server_address, "",
+              "The metrics server addresses in the fomrat <hostname>:<port>");
+
+using grpc::testing::EmptyMessage;
+using grpc::testing::GaugeResponse;
+using grpc::testing::MetricsService;
+using grpc::testing::MetricsServiceImpl;
+
+void PrintMetrics(grpc::string& server_address) {
+  gpr_log(GPR_INFO, "creating a channel to %s", server_address.c_str());
+  std::shared_ptr<grpc::Channel> channel(
+      grpc::CreateChannel(server_address, grpc::InsecureChannelCredentials()));
+
+  std::unique_ptr<MetricsService::Stub> stub(MetricsService::NewStub(channel));
+
+  grpc::ClientContext context;
+  EmptyMessage message;
+
+  std::unique_ptr<grpc::ClientReader<GaugeResponse>> reader(
+      stub->GetAllGauges(&context, message));
+
+  GaugeResponse gauge_response;
+  long overall_qps = 0;
+  int idx = 0;
+  while (reader->Read(&gauge_response)) {
+    if (gauge_response.value_case() == GaugeResponse::kLongValue) {
+      gpr_log(GPR_INFO, "Gauge: %d (%s: %ld)", ++idx,
+              gauge_response.name().c_str(), gauge_response.long_value());
+      overall_qps += gauge_response.long_value();
+    } else {
+      gpr_log(GPR_INFO, "Gauge %s is not a long value",
+              gauge_response.name().c_str());
+    }
+  }
+
+  gpr_log(GPR_INFO, "OVERALL: %ld", overall_qps);
+
+  const grpc::Status status = reader->Finish();
+  if (!status.ok()) {
+    gpr_log(GPR_ERROR, "Error in getting metrics from the client");
+  }
+}
+
+int main(int argc, char** argv) {
+  grpc::testing::InitTest(&argc, &argv, true);
+
+  // Make sure server_addresses flag is not empty
+  if (FLAGS_metrics_server_address.empty()) {
+    gpr_log(
+        GPR_ERROR,
+        "Cannot connect to the Metrics server. Please pass the address of the"
+        "metrics server to connect to via the 'metrics_server_address' flag");
+    return 1;
+  }
+
+  PrintMetrics(FLAGS_metrics_server_address);
+
+  return 0;
+}
diff --git a/test/cpp/interop/stress_interop_client.cc b/test/cpp/interop/stress_interop_client.cc
index 3be2571493..5d2951e3ed 100644
--- a/test/cpp/interop/stress_interop_client.cc
+++ b/test/cpp/interop/stress_interop_client.cc
@@ -40,6 +40,7 @@
 #include <grpc++/create_channel.h>
 
 #include "test/cpp/interop/interop_client.h"
+#include "test/cpp/util/metrics_server.h"
 
 namespace grpc {
 namespace testing {
@@ -81,21 +82,19 @@ TestCaseType WeightedRandomTestSelector::GetNextTest() const {
 
 StressTestInteropClient::StressTestInteropClient(
     int test_id, const grpc::string& server_address,
+    std::shared_ptr<Channel> channel,
     const WeightedRandomTestSelector& test_selector, long test_duration_secs,
-    long sleep_duration_ms)
+    long sleep_duration_ms, long metrics_collection_interval_secs)
     : test_id_(test_id),
       server_address_(server_address),
+      channel_(channel),
+      interop_client_(new InteropClient(channel, false)),
       test_selector_(test_selector),
       test_duration_secs_(test_duration_secs),
-      sleep_duration_ms_(sleep_duration_ms) {
-  // TODO(sreek): This will change once we add support for other tests
-  // that won't work with InsecureChannelCredentials()
-  std::shared_ptr<Channel> channel(
-      CreateChannel(server_address, InsecureChannelCredentials()));
-  interop_client_.reset(new InteropClient(channel, false));
-}
+      sleep_duration_ms_(sleep_duration_ms),
+      metrics_collection_interval_secs_(metrics_collection_interval_secs) {}
 
-void StressTestInteropClient::MainLoop() {
+void StressTestInteropClient::MainLoop(std::shared_ptr<Gauge> qps_gauge) {
   gpr_log(GPR_INFO, "Running test %d. ServerAddr: %s", test_id_,
           server_address_.c_str());
 
@@ -104,21 +103,38 @@ void StressTestInteropClient::MainLoop() {
                    gpr_time_from_seconds(test_duration_secs_, GPR_TIMESPAN));
 
   gpr_timespec current_time = gpr_now(GPR_CLOCK_REALTIME);
+  gpr_timespec next_stat_collection_time = current_time;
+  gpr_timespec collection_interval =
+      gpr_time_from_seconds(metrics_collection_interval_secs_, GPR_TIMESPAN);
+  long num_calls_per_interval = 0;
+
   while (test_duration_secs_ < 0 ||
-         gpr_time_cmp(current_time, test_end_time) < 0) {
+         gpr_time_cmp(gpr_now(GPR_CLOCK_REALTIME), test_end_time) < 0) {
     // Select the test case to execute based on the weights and execute it
     TestCaseType test_case = test_selector_.GetNextTest();
     gpr_log(GPR_INFO, "%d - Executing the test case %d", test_id_, test_case);
     RunTest(test_case);
 
+    num_calls_per_interval++;
+
+    // See if its time to collect stats yet
+    current_time = gpr_now(GPR_CLOCK_REALTIME);
+    if (gpr_time_cmp(next_stat_collection_time, current_time) < 0) {
+      qps_gauge->Set(num_calls_per_interval /
+                     metrics_collection_interval_secs_);
+
+      num_calls_per_interval = 0;
+      next_stat_collection_time =
+          gpr_time_add(current_time, collection_interval);
+    }
+
     // Sleep between successive calls if needed
     if (sleep_duration_ms_ > 0) {
-      gpr_timespec sleep_time = gpr_time_add(
-          current_time, gpr_time_from_millis(sleep_duration_ms_, GPR_TIMESPAN));
+      gpr_timespec sleep_time =
+          gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
+                       gpr_time_from_millis(sleep_duration_ms_, GPR_TIMESPAN));
       gpr_sleep_until(sleep_time);
     }
-
-    current_time = gpr_now(GPR_CLOCK_REALTIME);
   }
 }
 
diff --git a/test/cpp/interop/stress_interop_client.h b/test/cpp/interop/stress_interop_client.h
index 36261e501f..6fd303d6b7 100644
--- a/test/cpp/interop/stress_interop_client.h
+++ b/test/cpp/interop/stress_interop_client.h
@@ -41,6 +41,7 @@
 #include <grpc++/create_channel.h>
 
 #include "test/cpp/interop/interop_client.h"
+#include "test/cpp/util/metrics_server.h"
 
 namespace grpc {
 namespace testing {
@@ -84,20 +85,26 @@ class WeightedRandomTestSelector {
 class StressTestInteropClient {
  public:
   StressTestInteropClient(int test_id, const grpc::string& server_address,
+                          std::shared_ptr<Channel> channel,
                           const WeightedRandomTestSelector& test_selector,
-                          long test_duration_secs, long sleep_duration_ms);
+                          long test_duration_secs, long sleep_duration_ms,
+                          long metrics_collection_interval_secs);
 
-  void MainLoop();  // The main function. Use this as the thread entry point.
+  // The main function. Use this as the thread entry point.
+  // qps_gauge is the Gauge to record the requests per second metric
+  void MainLoop(std::shared_ptr<Gauge> qps_gauge);
 
  private:
   void RunTest(TestCaseType test_case);
 
   int test_id_;
-  std::unique_ptr<InteropClient> interop_client_;
   const grpc::string& server_address_;
+  std::shared_ptr<Channel> channel_;
+  std::unique_ptr<InteropClient> interop_client_;
   const WeightedRandomTestSelector& test_selector_;
   long test_duration_secs_;
   long sleep_duration_ms_;
+  long metrics_collection_interval_secs_;
 };
 
 }  // namespace testing
diff --git a/test/cpp/interop/stress_test.cc b/test/cpp/interop/stress_test.cc
index 018f4ab4f7..f6023a4cb3 100644
--- a/test/cpp/interop/stress_test.cc
+++ b/test/cpp/interop/stress_test.cc
@@ -45,7 +45,15 @@
 
 #include "test/cpp/interop/interop_client.h"
 #include "test/cpp/interop/stress_interop_client.h"
+#include "test/cpp/util/metrics_server.h"
 #include "test/cpp/util/test_config.h"
+#include "test/proto/metrics.grpc.pb.h"
+#include "test/proto/metrics.pb.h"
+
+DEFINE_int32(metrics_port, 8081, "The metrics server port.");
+
+DEFINE_int32(metrics_collection_interval_secs, 5,
+             "How often (in seconds) should metrics be recorded.");
 
 DEFINE_int32(sleep_duration_ms, 0,
              "The duration (in millisec) between two"
@@ -62,6 +70,11 @@ DEFINE_string(server_addresses, "localhost:8080",
               " \"<name_1>:<port_1>,<name_2>:<port_1>...<name_N>:<port_N>\"\n"
               " Note: <name> can be servername or IP address.");
 
+DEFINE_int32(num_stubs_per_channel, 1,
+             "Number of stubs per each channels to server. This number also "
+             "indicates the max number of parallel RPC calls on each channel "
+             "at any given time.");
+
 // TODO(sreek): Add more test cases here in future
 DEFINE_string(test_cases, "",
               "List of test cases to call along with the"
@@ -79,15 +92,13 @@ DEFINE_string(test_cases, "",
               " 'large_unary', 10% of the time and 'empty_stream' the remaining"
               " 70% of the time");
 
-using std::make_pair;
-using std::pair;
-using std::vector;
-
 using grpc::testing::kTestCaseList;
+using grpc::testing::MetricsService;
+using grpc::testing::MetricsServiceImpl;
 using grpc::testing::StressTestInteropClient;
 using grpc::testing::TestCaseType;
-using grpc::testing::WeightedRandomTestSelector;
 using grpc::testing::UNKNOWN_TEST;
+using grpc::testing::WeightedRandomTestSelector;
 
 TestCaseType GetTestTypeFromName(const grpc::string& test_name) {
   TestCaseType test_case = UNKNOWN_TEST;
@@ -104,7 +115,7 @@ TestCaseType GetTestTypeFromName(const grpc::string& test_name) {
 
 // Converts a string of comma delimited tokens to a vector of tokens
 bool ParseCommaDelimitedString(const grpc::string& comma_delimited_str,
-                               vector<grpc::string>& tokens) {
+                               std::vector<grpc::string>& tokens) {
   size_t bpos = 0;
   size_t epos = grpc::string::npos;
 
@@ -122,10 +133,10 @@ bool ParseCommaDelimitedString(const grpc::string& comma_delimited_str,
 //   - Whether parsing was successful (return value)
 //   - Vector of (test_type_enum, weight) pairs returned via 'tests' parameter
 bool ParseTestCasesString(const grpc::string& test_cases,
-                          vector<pair<TestCaseType, int>>& tests) {
+                          std::vector<std::pair<TestCaseType, int>>& tests) {
   bool is_success = true;
 
-  vector<grpc::string> tokens;
+  std::vector<grpc::string> tokens;
   ParseCommaDelimitedString(test_cases, tokens);
 
   for (auto it = tokens.begin(); it != tokens.end(); it++) {
@@ -153,8 +164,8 @@ bool ParseTestCasesString(const grpc::string& test_cases,
 }
 
 // For debugging purposes
-void LogParameterInfo(const vector<grpc::string>& addresses,
-                      const vector<pair<TestCaseType, int>>& tests) {
+void LogParameterInfo(const std::vector<grpc::string>& addresses,
+                      const std::vector<std::pair<TestCaseType, int>>& tests) {
   gpr_log(GPR_INFO, "server_addresses: %s", FLAGS_server_addresses.c_str());
   gpr_log(GPR_INFO, "test_cases : %s", FLAGS_test_cases.c_str());
   gpr_log(GPR_INFO, "sleep_duration_ms: %d", FLAGS_sleep_duration_ms);
@@ -180,7 +191,7 @@ int main(int argc, char** argv) {
   srand(time(NULL));
 
   // Parse the server addresses
-  vector<grpc::string> server_addresses;
+  std::vector<grpc::string> server_addresses;
   ParseCommaDelimitedString(FLAGS_server_addresses, server_addresses);
 
   // Parse test cases and weights
@@ -189,7 +200,7 @@ int main(int argc, char** argv) {
     return 1;
   }
 
-  vector<pair<TestCaseType, int>> tests;
+  std::vector<std::pair<TestCaseType, int>> tests;
   if (!ParseTestCasesString(FLAGS_test_cases, tests)) {
     gpr_log(GPR_ERROR, "Error in parsing test cases string %s ",
             FLAGS_test_cases.c_str());
@@ -199,23 +210,48 @@ int main(int argc, char** argv) {
   LogParameterInfo(server_addresses, tests);
 
   WeightedRandomTestSelector test_selector(tests);
+  MetricsServiceImpl metrics_service;
 
   gpr_log(GPR_INFO, "Starting test(s)..");
 
-  vector<grpc::thread> test_threads;
+  std::vector<grpc::thread> test_threads;
+
   int thread_idx = 0;
   for (auto it = server_addresses.begin(); it != server_addresses.end(); it++) {
-    StressTestInteropClient* client = new StressTestInteropClient(
-        ++thread_idx, *it, test_selector, FLAGS_test_duration_secs,
-        FLAGS_sleep_duration_ms);
-
-    test_threads.emplace_back(
-        grpc::thread(&StressTestInteropClient::MainLoop, client));
+    // TODO(sreek): This will change once we add support for other tests
+    // that won't work with InsecureChannelCredentials()
+    std::shared_ptr<grpc::Channel> channel(
+        grpc::CreateChannel(*it, grpc::InsecureChannelCredentials()));
+
+    // Make multiple stubs (as defined by num_stubs_per_channel flag) to use the
+    // same channel. This is to test calling multiple RPC calls in parallel on
+    // each channel.
+    for (int i = 0; i < FLAGS_num_stubs_per_channel; i++) {
+      StressTestInteropClient* client = new StressTestInteropClient(
+          ++thread_idx, *it, channel, test_selector, FLAGS_test_duration_secs,
+          FLAGS_sleep_duration_ms, FLAGS_metrics_collection_interval_secs);
+
+      bool is_already_created;
+      grpc::string metricName =
+          "/stress_test/qps/thread/" + std::to_string(thread_idx);
+      test_threads.emplace_back(grpc::thread(
+          &StressTestInteropClient::MainLoop, client,
+          metrics_service.CreateGauge(metricName, &is_already_created)));
+
+      // The Gauge should not have been already created
+      GPR_ASSERT(!is_already_created);
+    }
   }
 
+  // Start metrics server before waiting for the stress test threads
+  std::unique_ptr<grpc::Server> metrics_server =
+      metrics_service.StartServer(FLAGS_metrics_port);
+
+  // Wait for the stress test threads to complete
   for (auto it = test_threads.begin(); it != test_threads.end(); it++) {
     it->join();
   }
 
+  metrics_server->Wait();
   return 0;
 }
diff --git a/test/cpp/qps/async_streaming_ping_pong_test.cc b/test/cpp/qps/async_streaming_ping_pong_test.cc
index 9fef93a70f..0acdf3affb 100644
--- a/test/cpp/qps/async_streaming_ping_pong_test.cc
+++ b/test/cpp/qps/async_streaming_ping_pong_test.cc
@@ -58,6 +58,7 @@ static void RunAsyncStreamingPingPong() {
 
   ServerConfig server_config;
   server_config.set_server_type(ASYNC_SERVER);
+  server_config.set_host("localhost");
   server_config.set_async_server_threads(1);
 
   const auto result =
diff --git a/test/cpp/qps/async_unary_ping_pong_test.cc b/test/cpp/qps/async_unary_ping_pong_test.cc
index b4ab0e5d59..d21e116171 100644
--- a/test/cpp/qps/async_unary_ping_pong_test.cc
+++ b/test/cpp/qps/async_unary_ping_pong_test.cc
@@ -58,6 +58,7 @@ static void RunAsyncUnaryPingPong() {
 
   ServerConfig server_config;
   server_config.set_server_type(ASYNC_SERVER);
+  server_config.set_host("localhost");
   server_config.set_async_server_threads(1);
 
   const auto result =
diff --git a/test/cpp/qps/client.h b/test/cpp/qps/client.h
index f4400692fe..b24a90adac 100644
--- a/test/cpp/qps/client.h
+++ b/test/cpp/qps/client.h
@@ -181,29 +181,29 @@ class Client {
 
     std::unique_ptr<RandomDist> random_dist;
     switch (load.load_case()) {
-    case LoadParams::kClosedLoop:
-      // Closed-loop doesn't use random dist at all
-      break;
-    case LoadParams::kPoisson:
-      random_dist.reset(
-          new ExpDist(load.poisson().offered_load() / num_threads));
-      break;
-    case LoadParams::kUniform:
-      random_dist.reset(
-          new UniformDist(load.uniform().interarrival_lo() * num_threads,
-                          load.uniform().interarrival_hi() * num_threads));
-      break;
-    case LoadParams::kDeterm:
-      random_dist.reset(
-          new DetDist(num_threads / load.determ().offered_load()));
-      break;
-    case LoadParams::kPareto:
-      random_dist.reset(
-          new ParetoDist(load.pareto().interarrival_base() * num_threads,
-                         load.pareto().alpha()));
-      break;
-    default:
-      GPR_ASSERT(false);
+      case LoadParams::kClosedLoop:
+        // Closed-loop doesn't use random dist at all
+        break;
+      case LoadParams::kPoisson:
+        random_dist.reset(
+            new ExpDist(load.poisson().offered_load() / num_threads));
+        break;
+      case LoadParams::kUniform:
+        random_dist.reset(
+            new UniformDist(load.uniform().interarrival_lo() * num_threads,
+                            load.uniform().interarrival_hi() * num_threads));
+        break;
+      case LoadParams::kDeterm:
+        random_dist.reset(
+            new DetDist(num_threads / load.determ().offered_load()));
+        break;
+      case LoadParams::kPareto:
+        random_dist.reset(
+            new ParetoDist(load.pareto().interarrival_base() * num_threads,
+                           load.pareto().alpha()));
+        break;
+      default:
+        GPR_ASSERT(false);
     }
 
     // Set closed_loop_ based on whether or not random_dist is set
diff --git a/test/cpp/qps/driver.cc b/test/cpp/qps/driver.cc
index 67bdcb2f32..20dc65046b 100644
--- a/test/cpp/qps/driver.cc
+++ b/test/cpp/qps/driver.cc
@@ -110,7 +110,7 @@ std::unique_ptr<ScenarioResult> RunScenario(
   list<ClientContext> contexts;
 
   // To be added to the result, containing the final configuration used for
-  // client and config (incluiding host, etc.)
+  // client and config (including host, etc.)
   ClientConfig result_client_config;
   ServerConfig result_server_config;
 
diff --git a/test/cpp/qps/histogram.h b/test/cpp/qps/histogram.h
index 35527d2a2c..4161eac826 100644
--- a/test/cpp/qps/histogram.h
+++ b/test/cpp/qps/histogram.h
@@ -42,7 +42,10 @@ namespace testing {
 
 class Histogram {
  public:
-  Histogram() : impl_(gpr_histogram_create(0.01, 60e9)) {}
+  // TODO: look into making histogram params not hardcoded for C++
+  Histogram()
+      : impl_(gpr_histogram_create(default_resolution(),
+                                   default_max_possible())) {}
   ~Histogram() {
     if (impl_) gpr_histogram_destroy(impl_);
   }
@@ -73,6 +76,9 @@ class Histogram {
                                  p.sum_of_squares(), p.count());
   }
 
+  static double default_resolution() { return 0.01; }
+  static double default_max_possible() { return 60e9; }
+
  private:
   Histogram(const Histogram&);
   Histogram& operator=(const Histogram&);
diff --git a/test/cpp/qps/qps_driver.cc b/test/cpp/qps/qps_driver.cc
index 4c93a042cf..c7096391e6 100644
--- a/test/cpp/qps/qps_driver.cc
+++ b/test/cpp/qps/qps_driver.cc
@@ -137,8 +137,14 @@ static void QpsDriver() {
     // No further load parameters to set up for closed loop
   }
 
+  client_config.mutable_histogram_params()->set_resolution(
+      Histogram::default_resolution());
+  client_config.mutable_histogram_params()->set_max_possible(
+      Histogram::default_max_possible());
+
   ServerConfig server_config;
   server_config.set_server_type(server_type);
+  server_config.set_host("localhost");
   server_config.set_async_server_threads(FLAGS_async_server_threads);
 
   if (FLAGS_secure_test) {
diff --git a/test/cpp/qps/qps_openloop_test.cc b/test/cpp/qps/qps_openloop_test.cc
index dc88c893bb..51df79ef2f 100644
--- a/test/cpp/qps/qps_openloop_test.cc
+++ b/test/cpp/qps/qps_openloop_test.cc
@@ -59,6 +59,7 @@ static void RunQPS() {
 
   ServerConfig server_config;
   server_config.set_server_type(ASYNC_SERVER);
+  server_config.set_host("localhost");
   server_config.set_async_server_threads(4);
 
   const auto result =
diff --git a/test/cpp/qps/qps_test.cc b/test/cpp/qps/qps_test.cc
index 89b35cfb05..1f87d18137 100644
--- a/test/cpp/qps/qps_test.cc
+++ b/test/cpp/qps/qps_test.cc
@@ -58,6 +58,7 @@ static void RunQPS() {
 
   ServerConfig server_config;
   server_config.set_server_type(ASYNC_SERVER);
+  server_config.set_host("localhost");
   server_config.set_async_server_threads(8);
 
   const auto result =
diff --git a/test/cpp/qps/qps_test_with_poll.cc b/test/cpp/qps/qps_test_with_poll.cc
index 97da4096ed..dc800092db 100644
--- a/test/cpp/qps/qps_test_with_poll.cc
+++ b/test/cpp/qps/qps_test_with_poll.cc
@@ -62,6 +62,7 @@ static void RunQPS() {
 
   ServerConfig server_config;
   server_config.set_server_type(ASYNC_SERVER);
+  server_config.set_host("localhost");
   server_config.set_async_server_threads(4);
 
   const auto result =
diff --git a/test/cpp/qps/secure_sync_unary_ping_pong_test.cc b/test/cpp/qps/secure_sync_unary_ping_pong_test.cc
index df06f7e471..ce9f02cceb 100644
--- a/test/cpp/qps/secure_sync_unary_ping_pong_test.cc
+++ b/test/cpp/qps/secure_sync_unary_ping_pong_test.cc
@@ -57,6 +57,7 @@ static void RunSynchronousUnaryPingPong() {
 
   ServerConfig server_config;
   server_config.set_server_type(SYNC_SERVER);
+  server_config.set_host("localhost");
 
   // Set up security params
   SecurityParams security;
diff --git a/test/cpp/qps/server_async.cc b/test/cpp/qps/server_async.cc
index 2d922fa615..c151918ce4 100644
--- a/test/cpp/qps/server_async.cc
+++ b/test/cpp/qps/server_async.cc
@@ -60,7 +60,7 @@ class AsyncQpsServerTest : public Server {
   explicit AsyncQpsServerTest(const ServerConfig &config) : Server(config) {
     char *server_address = NULL;
 
-    gpr_join_host_port(&server_address, "::", port());
+    gpr_join_host_port(&server_address, config.host().c_str(), port());
 
     ServerBuilder builder;
     builder.AddListeningPort(server_address,
diff --git a/test/cpp/qps/server_sync.cc b/test/cpp/qps/server_sync.cc
index a09b174b7e..3a15bec888 100644
--- a/test/cpp/qps/server_sync.cc
+++ b/test/cpp/qps/server_sync.cc
@@ -89,7 +89,7 @@ class SynchronousServer GRPC_FINAL : public grpc::testing::Server {
 
     char* server_address = NULL;
 
-    gpr_join_host_port(&server_address, "::", port());
+    gpr_join_host_port(&server_address, config.host().c_str(), port());
     builder.AddListeningPort(server_address,
                              Server::CreateServerCredentials(config));
     gpr_free(server_address);
diff --git a/test/cpp/qps/sync_streaming_ping_pong_test.cc b/test/cpp/qps/sync_streaming_ping_pong_test.cc
index 186afc03f7..dd8c682815 100644
--- a/test/cpp/qps/sync_streaming_ping_pong_test.cc
+++ b/test/cpp/qps/sync_streaming_ping_pong_test.cc
@@ -57,6 +57,7 @@ static void RunSynchronousStreamingPingPong() {
 
   ServerConfig server_config;
   server_config.set_server_type(SYNC_SERVER);
+  server_config.set_host("localhost");
 
   const auto result =
       RunScenario(client_config, 1, server_config, 1, WARMUP, BENCHMARK, -2);
diff --git a/test/cpp/qps/sync_unary_ping_pong_test.cc b/test/cpp/qps/sync_unary_ping_pong_test.cc
index 25851833a6..2edb33ef01 100644
--- a/test/cpp/qps/sync_unary_ping_pong_test.cc
+++ b/test/cpp/qps/sync_unary_ping_pong_test.cc
@@ -57,6 +57,7 @@ static void RunSynchronousUnaryPingPong() {
 
   ServerConfig server_config;
   server_config.set_server_type(SYNC_SERVER);
+  server_config.set_host("localhost");
 
   const auto result =
       RunScenario(client_config, 1, server_config, 1, WARMUP, BENCHMARK, -2);
diff --git a/test/cpp/util/metrics_server.cc b/test/cpp/util/metrics_server.cc
new file mode 100644
index 0000000000..426295f9b4
--- /dev/null
+++ b/test/cpp/util/metrics_server.cc
@@ -0,0 +1,119 @@
+/*
+ *
+ * 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.
+ *is % allowed in string
+ */
+
+#include "test/cpp/util/metrics_server.h"
+
+#include <grpc++/server_builder.h>
+
+#include "test/proto/metrics.grpc.pb.h"
+#include "test/proto/metrics.pb.h"
+
+namespace grpc {
+namespace testing {
+
+Gauge::Gauge(long initial_val) : val_(initial_val) {}
+
+void Gauge::Set(long new_val) {
+  std::lock_guard<std::mutex> lock(val_mu_);
+  val_ = new_val;
+}
+
+long Gauge::Get() {
+  std::lock_guard<std::mutex> lock(val_mu_);
+  return val_;
+}
+
+grpc::Status MetricsServiceImpl::GetAllGauges(
+    ServerContext* context, const EmptyMessage* request,
+    ServerWriter<GaugeResponse>* writer) {
+  gpr_log(GPR_INFO, "GetAllGauges called");
+
+  std::lock_guard<std::mutex> lock(mu_);
+  for (auto it = gauges_.begin(); it != gauges_.end(); it++) {
+    GaugeResponse resp;
+    resp.set_name(it->first);                // Gauge name
+    resp.set_long_value(it->second->Get());  // Gauge value
+    writer->Write(resp);
+  }
+
+  return Status::OK;
+}
+
+grpc::Status MetricsServiceImpl::GetGauge(ServerContext* context,
+                                          const GaugeRequest* request,
+                                          GaugeResponse* response) {
+  std::lock_guard<std::mutex> lock(mu_);
+
+  const auto it = gauges_.find(request->name());
+  if (it != gauges_.end()) {
+    response->set_name(it->first);
+    response->set_long_value(it->second->Get());
+  }
+
+  return Status::OK;
+}
+
+std::shared_ptr<Gauge> MetricsServiceImpl::CreateGauge(const grpc::string& name,
+                                                       bool* already_present) {
+  std::lock_guard<std::mutex> lock(mu_);
+
+  std::shared_ptr<Gauge> gauge(new Gauge(0));
+  const auto p = gauges_.emplace(name, gauge);
+
+  // p.first is an iterator pointing to <name, shared_ptr<Gauge>> pair. p.second
+  // is a boolean which is set to 'true' if the Gauge is inserted in the guages_
+  // map and 'false' if it is already present in the map
+  *already_present = !p.second;
+  return p.first->second;
+}
+
+// Starts the metrics server and returns the grpc::Server instance. Call Wait()
+// on the returned server instance.
+std::unique_ptr<grpc::Server> MetricsServiceImpl::StartServer(int port) {
+  gpr_log(GPR_INFO, "Building metrics server..");
+
+  const grpc::string address = "0.0.0.0:" + std::to_string(port);
+
+  ServerBuilder builder;
+  builder.AddListeningPort(address, grpc::InsecureServerCredentials());
+  builder.RegisterService(this);
+
+  std::unique_ptr<grpc::Server> server(builder.BuildAndStart());
+  gpr_log(GPR_INFO, "Metrics server %s started. Ready to receive requests..",
+          address.c_str());
+
+  return server;
+}
+
+}  // namespace testing
+}  // namespace grpc
diff --git a/test/cpp/util/metrics_server.h b/test/cpp/util/metrics_server.h
new file mode 100644
index 0000000000..edde37dc4c
--- /dev/null
+++ b/test/cpp/util/metrics_server.h
@@ -0,0 +1,100 @@
+/*
+ *
+ * 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.
+ *is % allowed in string
+ */
+#ifndef GRPC_TEST_CPP_METRICS_SERVER_H
+#define GRPC_TEST_CPP_METRICS_SERVER_H
+
+#include <map>
+#include <mutex>
+
+#include "test/proto/metrics.grpc.pb.h"
+#include "test/proto/metrics.pb.h"
+
+/*
+ * This implements a Metrics server defined in test/proto/metrics.proto. Any
+ * test service can use this to export Metrics (TODO (sreek): Only Gauges for
+ * now).
+ *
+ * Example:
+ *    MetricsServiceImpl metricsImpl;
+ *    ..
+ *    // Create Gauge(s). Note: Gauges can be created even after calling
+ *    // 'StartServer'.
+ *    Gauge gauge1 = metricsImpl.CreateGauge("foo",is_present);
+ *    // gauge1 can now be used anywhere in the program to set values.
+ *    ...
+ *    // Create the metrics server
+ *    std::unique_ptr<grpc::Server> server = metricsImpl.StartServer(port);
+ *    server->Wait(); // Note: This is blocking.
+ */
+namespace grpc {
+namespace testing {
+
+// TODO(sreek): Add support for other types of Gauges like Double, String in
+// future
+class Gauge {
+ public:
+  Gauge(long initial_val);
+  void Set(long new_val);
+  long Get();
+
+ private:
+  long val_;
+  std::mutex val_mu_;
+};
+
+class MetricsServiceImpl GRPC_FINAL : public MetricsService::Service {
+ public:
+  grpc::Status GetAllGauges(ServerContext* context, const EmptyMessage* request,
+                            ServerWriter<GaugeResponse>* writer) GRPC_OVERRIDE;
+
+  grpc::Status GetGauge(ServerContext* context, const GaugeRequest* request,
+                        GaugeResponse* response) GRPC_OVERRIDE;
+
+  // Create a Gauge with name 'name'. is_present is set to true if the Gauge
+  // is already present in the map.
+  // NOTE: CreateGauge can be called anytime (i.e before or after calling
+  // StartServer).
+  std::shared_ptr<Gauge> CreateGauge(const grpc::string& name,
+                                     bool* already_present);
+
+  std::unique_ptr<grpc::Server> StartServer(int port);
+
+ private:
+  std::map<string, std::shared_ptr<Gauge>> gauges_;
+  std::mutex mu_;
+};
+
+}  // namespace testing
+}  // namespace grpc
+
+#endif  // GRPC_TEST_CPP_METRICS_SERVER_H
diff --git a/test/proto/benchmarks/control.proto b/test/proto/benchmarks/control.proto
index 966ab78baa..42a5dd0a85 100644
--- a/test/proto/benchmarks/control.proto
+++ b/test/proto/benchmarks/control.proto
@@ -49,7 +49,10 @@ enum RpcType {
   STREAMING = 1;
 }
 
+// Parameters of poisson process distribution, which is a good representation
+// of activity coming in from independent identical stationary sources.
 message PoissonParams {
+  // The rate of arrivals (a.k.a. lambda parameter of the exp distribution).
   double offered_load = 1;
 }
 
@@ -67,6 +70,8 @@ message ParetoParams {
   double alpha = 2;
 }
 
+// Once an RPC finishes, immediately start a new one.
+// No configuration parameters needed.
 message ClosedLoopParams {
 }
 
@@ -87,16 +92,23 @@ message SecurityParams {
 }
 
 message ClientConfig {
+  // List of targets to connect to. At least one target needs to be specified.
   repeated string server_targets = 1;
   ClientType client_type = 2;
   SecurityParams security_params = 3;
+  // How many concurrent RPCs to start for each channel.
+  // For synchronous client, use a separate thread for each outstanding RPC.
   int32 outstanding_rpcs_per_channel = 4;
+  // Number of independent client channels to create.
+  // i-th channel will connect to server_target[i % server_targets.size()]
   int32 client_channels = 5;
-  // only for async client:
+  // Only for async client. Number of threads to use to start/manage RPCs.
   int32 async_client_threads = 7;
   RpcType rpc_type = 8;
+  // The requested load for the entire client (aggregated over all the threads).
   LoadParams load_params = 10;
   PayloadConfig payload_config = 11;
+  HistogramParams histogram_params = 12;
 }
 
 message ClientStatus {
@@ -105,6 +117,7 @@ message ClientStatus {
 
 // Request current stats
 message Mark {
+  // if true, the stats will be reset after taking their snapshot.
   bool reset = 1;
 }
 
@@ -118,10 +131,13 @@ message ClientArgs {
 message ServerConfig {
   ServerType server_type = 1;
   SecurityParams security_params = 2;
+  // Host on which to listen.
+  string host = 3;
+  // Port on which to listen. Zero means pick unused port.
   int32 port = 4;
-  // only for async server
+  // Only for async server. Number of threads used to serve the requests.
   int32 async_server_threads = 7;
-  // restrict core usage
+  // restrict core usage, currently unused
   int32 core_limit = 8;
   PayloadConfig payload_config = 9;
 }
@@ -135,6 +151,8 @@ message ServerArgs {
 
 message ServerStatus {
   ServerStats stats = 1;
+  // the port bound by the server
   int32 port = 2;
+  // Number of cores on the server. See gpr_cpu_num_cores.
   int32 cores = 3;
 }
diff --git a/test/proto/benchmarks/services.proto b/test/proto/benchmarks/services.proto
index 4c2cbabdf8..ff295ed970 100644
--- a/test/proto/benchmarks/services.proto
+++ b/test/proto/benchmarks/services.proto
@@ -47,9 +47,19 @@ service BenchmarkService {
 }
 
 service WorkerService {
-  // Start server with specified workload
+  // Start server with specified workload.
+  // First request sent specifies the ServerConfig followed by ServerStatus
+  // response. After that, a "Mark" can be sent anytime to request the latest
+  // stats. Closing the stream will initiate shutdown of the test server
+  // and once the shutdown has finished, the OK status is sent to terminate
+  // this RPC.
   rpc RunServer(stream ServerArgs) returns (stream ServerStatus);
 
-  // Start client with specified workload
+  // Start client with specified workload.
+  // First request sent specifies the ClientConfig followed by ClientStatus
+  // response. After that, a "Mark" can be sent anytime to request the latest
+  // stats. Closing the stream will initiate shutdown of the test client
+  // and once the shutdown has finished, the OK status is sent to terminate
+  // this RPC.
   rpc RunClient(stream ClientArgs) returns (stream ClientStatus);
 }
diff --git a/test/proto/benchmarks/stats.proto b/test/proto/benchmarks/stats.proto
index d52144f321..7e02707dbb 100644
--- a/test/proto/benchmarks/stats.proto
+++ b/test/proto/benchmarks/stats.proto
@@ -32,16 +32,24 @@ syntax = "proto3";
 package grpc.testing;
 
 message ServerStats {
-  // wall clock time
+  // wall clock time change in seconds since last reset
   double time_elapsed = 1;
 
-  // user time used by the server process and threads
+  // change in user time (in seconds) used by the server since last reset
   double time_user = 2;
 
-  // server time used by the server process and all threads
+  // change in server time (in seconds) used by the server process and all
+  // threads since last reset
   double time_system = 3;
 }
 
+// Histogram params based on grpc/support/histogram.c
+message HistogramParams {
+  double resolution = 1;    // first bucket is [0, 1 + resolution)
+  double max_possible = 2;  // use enough buckets to allow this value
+}
+
+// Histogram data based on grpc/support/histogram.c
 message HistogramData {
   repeated uint32 bucket = 1;
   double min_seen = 2;
@@ -52,7 +60,10 @@ message HistogramData {
 }
 
 message ClientStats {
+  // Latency histogram. Data points are in nanoseconds.
   HistogramData latencies = 1;
+
+  // See ServerStats for details.
   double time_elapsed = 2;
   double time_user = 3;
   double time_system = 4;
diff --git a/test/proto/metrics.proto b/test/proto/metrics.proto
new file mode 100644
index 0000000000..f5a08e056a
--- /dev/null
+++ b/test/proto/metrics.proto
@@ -0,0 +1,56 @@
+
+// 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.
+
+// An integration test service that covers all the method signature permutations
+// of unary/streaming requests/responses.
+syntax = "proto3";
+
+package grpc.testing;
+
+message GaugeResponse {
+  string name = 1;
+  oneof value {
+    int64 long_value = 2;
+    double double_vale = 3;
+    string string_value = 4;
+  }
+}
+
+message GaugeRequest {
+  string name = 1;
+}
+
+message EmptyMessage {
+}
+
+service MetricsService {
+  rpc GetAllGauges(EmptyMessage) returns (stream GaugeResponse);
+  rpc GetGauge(GaugeRequest) returns (GaugeResponse);
+}