Merge pull request #11309 from murgatroid99/master_1.3.x_upmerge

Master 1.3.x upmerge

48 files changed, 1628 insertions, 269 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1635d5dc2d..fd53f621a6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -482,6 +482,7 @@ add_dependencies(buildtests_c mlog_test)
 add_dependencies(buildtests_c multiple_server_queues_test)
 add_dependencies(buildtests_c murmur_hash_test)
 add_dependencies(buildtests_c no_server_test)
+add_dependencies(buildtests_c num_external_connectivity_watchers_test)
 add_dependencies(buildtests_c parse_address_test)
 add_dependencies(buildtests_c percent_encoding_test)
 if(_gRPC_PLATFORM_LINUX)
@@ -7523,6 +7524,37 @@ target_link_libraries(no_server_test
 endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
 
+add_executable(num_external_connectivity_watchers_test
+  test/core/surface/num_external_connectivity_watchers_test.c
+)
+
+
+target_include_directories(num_external_connectivity_watchers_test
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PRIVATE ${BORINGSSL_ROOT_DIR}/include
+  PRIVATE ${PROTOBUF_ROOT_DIR}/src
+  PRIVATE ${BENCHMARK_ROOT_DIR}/include
+  PRIVATE ${ZLIB_ROOT_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/zlib
+  PRIVATE ${CARES_BUILD_INCLUDE_DIR}
+  PRIVATE ${CARES_INCLUDE_DIR}
+  PRIVATE ${CARES_PLATFORM_INCLUDE_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/cares/cares
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/gflags/include
+)
+
+target_link_libraries(num_external_connectivity_watchers_test
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpc_test_util
+  grpc
+  gpr_test_util
+  gpr
+)
+
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
+
 add_executable(parse_address_test
   test/core/client_channel/parse_address_test.c
 )
diff --git a/Makefile b/Makefile
index 188ca8b268..82b2104b4a 100644
--- a/Makefile
+++ b/Makefile
@@ -1063,6 +1063,7 @@ murmur_hash_test: $(BINDIR)/$(CONFIG)/murmur_hash_test
 nanopb_fuzzer_response_test: $(BINDIR)/$(CONFIG)/nanopb_fuzzer_response_test
 nanopb_fuzzer_serverlist_test: $(BINDIR)/$(CONFIG)/nanopb_fuzzer_serverlist_test
 no_server_test: $(BINDIR)/$(CONFIG)/no_server_test
+num_external_connectivity_watchers_test: $(BINDIR)/$(CONFIG)/num_external_connectivity_watchers_test
 parse_address_test: $(BINDIR)/$(CONFIG)/parse_address_test
 percent_decode_fuzzer: $(BINDIR)/$(CONFIG)/percent_decode_fuzzer
 percent_encode_fuzzer: $(BINDIR)/$(CONFIG)/percent_encode_fuzzer
@@ -1442,6 +1443,7 @@ buildtests_c: privatelibs_c \
   $(BINDIR)/$(CONFIG)/multiple_server_queues_test \
   $(BINDIR)/$(CONFIG)/murmur_hash_test \
   $(BINDIR)/$(CONFIG)/no_server_test \
+  $(BINDIR)/$(CONFIG)/num_external_connectivity_watchers_test \
   $(BINDIR)/$(CONFIG)/parse_address_test \
   $(BINDIR)/$(CONFIG)/percent_encoding_test \
   $(BINDIR)/$(CONFIG)/pollset_set_test \
@@ -1911,6 +1913,8 @@ test_c: buildtests_c
 	$(Q) $(BINDIR)/$(CONFIG)/murmur_hash_test || ( echo test murmur_hash_test failed ; exit 1 )
 	$(E) "[RUN]     Testing no_server_test"
 	$(Q) $(BINDIR)/$(CONFIG)/no_server_test || ( echo test no_server_test failed ; exit 1 )
+	$(E) "[RUN]     Testing num_external_connectivity_watchers_test"
+	$(Q) $(BINDIR)/$(CONFIG)/num_external_connectivity_watchers_test || ( echo test num_external_connectivity_watchers_test failed ; exit 1 )
 	$(E) "[RUN]     Testing parse_address_test"
 	$(Q) $(BINDIR)/$(CONFIG)/parse_address_test || ( echo test parse_address_test failed ; exit 1 )
 	$(E) "[RUN]     Testing percent_encoding_test"
@@ -11766,6 +11770,38 @@ endif
 endif
 
 
+NUM_EXTERNAL_CONNECTIVITY_WATCHERS_TEST_SRC = \
+    test/core/surface/num_external_connectivity_watchers_test.c \
+
+NUM_EXTERNAL_CONNECTIVITY_WATCHERS_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(NUM_EXTERNAL_CONNECTIVITY_WATCHERS_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/num_external_connectivity_watchers_test: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/num_external_connectivity_watchers_test: $(NUM_EXTERNAL_CONNECTIVITY_WATCHERS_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LD) $(LDFLAGS) $(NUM_EXTERNAL_CONNECTIVITY_WATCHERS_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBS) $(LDLIBS_SECURE) -o $(BINDIR)/$(CONFIG)/num_external_connectivity_watchers_test
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/surface/num_external_connectivity_watchers_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_num_external_connectivity_watchers_test: $(NUM_EXTERNAL_CONNECTIVITY_WATCHERS_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(NUM_EXTERNAL_CONNECTIVITY_WATCHERS_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 PARSE_ADDRESS_TEST_SRC = \
     test/core/client_channel/parse_address_test.c \
 
diff --git a/build.yaml b/build.yaml
index d2ea16c8c2..26144e33de 100644
--- a/build.yaml
+++ b/build.yaml
@@ -2707,6 +2707,18 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: num_external_connectivity_watchers_test
+  build: test
+  language: c
+  src:
+  - test/core/surface/num_external_connectivity_watchers_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
+  exclude_iomgrs:
+  - uv
 - name: parse_address_test
   build: test
   language: c
diff --git a/grpc.def b/grpc.def
index 55b27c2c24..af4bd1674f 100644
--- a/grpc.def
+++ b/grpc.def
@@ -65,6 +65,7 @@ EXPORTS
     grpc_alarm_cancel
     grpc_alarm_destroy
     grpc_channel_check_connectivity_state
+    grpc_channel_num_external_connectivity_watchers
     grpc_channel_watch_connectivity_state
     grpc_channel_create_call
     grpc_channel_ping
diff --git a/include/grpc/grpc.h b/include/grpc/grpc.h
index a36367fa8f..47d1ea6238 100644
--- a/include/grpc/grpc.h
+++ b/include/grpc/grpc.h
@@ -178,6 +178,12 @@ GRPCAPI void grpc_alarm_destroy(grpc_alarm *alarm);
 GRPCAPI grpc_connectivity_state grpc_channel_check_connectivity_state(
     grpc_channel *channel, int try_to_connect);
 
+/** Number of active "external connectivity state watchers" attached to a
+ * channel.
+ * Useful for testing. **/
+GRPCAPI int grpc_channel_num_external_connectivity_watchers(
+    grpc_channel *channel);
+
 /** Watch for a change in connectivity state.
     Once the channel connectivity state is different from last_observed_state,
     tag will be enqueued on cq with success=1.
diff --git a/src/core/ext/filters/client_channel/channel_connectivity.c b/src/core/ext/filters/client_channel/channel_connectivity.c
index f83670db82..04666edbec 100644
--- a/src/core/ext/filters/client_channel/channel_connectivity.c
+++ b/src/core/ext/filters/client_channel/channel_connectivity.c
@@ -67,9 +67,8 @@ grpc_connectivity_state grpc_channel_check_connectivity_state(
 
 typedef enum {
   WAITING,
-  CALLING_BACK,
+  READY_TO_CALL_BACK,
   CALLING_BACK_AND_FINISHED,
-  CALLED_BACK
 } callback_phase;
 
 typedef struct {
@@ -77,11 +76,13 @@ typedef struct {
   callback_phase phase;
   grpc_closure on_complete;
   grpc_closure on_timeout;
+  grpc_closure watcher_timer_init;
   grpc_timer alarm;
   grpc_connectivity_state state;
   grpc_completion_queue *cq;
   grpc_cq_completion completion_storage;
   grpc_channel *channel;
+  grpc_error *error;
   void *tag;
 } state_watcher;
 
@@ -105,11 +106,8 @@ static void finished_completion(grpc_exec_ctx *exec_ctx, void *pw,
   gpr_mu_lock(&w->mu);
   switch (w->phase) {
     case WAITING:
-    case CALLED_BACK:
+    case READY_TO_CALL_BACK:
       GPR_UNREACHABLE_CODE(return );
-    case CALLING_BACK:
-      w->phase = CALLED_BACK;
-      break;
     case CALLING_BACK_AND_FINISHED:
       delete = 1;
       break;
@@ -123,10 +121,14 @@ static void finished_completion(grpc_exec_ctx *exec_ctx, void *pw,
 
 static void partly_done(grpc_exec_ctx *exec_ctx, state_watcher *w,
                         bool due_to_completion, grpc_error *error) {
-  int delete = 0;
-
   if (due_to_completion) {
     grpc_timer_cancel(exec_ctx, &w->alarm);
+  } else {
+    grpc_channel_element *client_channel_elem = grpc_channel_stack_last_element(
+        grpc_channel_get_channel_stack(w->channel));
+    grpc_client_channel_watch_connectivity_state(exec_ctx, client_channel_elem,
+                                                 grpc_cq_pollset(w->cq), NULL,
+                                                 &w->on_complete, NULL);
   }
 
   gpr_mu_lock(&w->mu);
@@ -147,25 +149,27 @@ static void partly_done(grpc_exec_ctx *exec_ctx, state_watcher *w,
   }
   switch (w->phase) {
     case WAITING:
-      w->phase = CALLING_BACK;
-      grpc_cq_end_op(exec_ctx, w->cq, w->tag, GRPC_ERROR_REF(error),
-                     finished_completion, w, &w->completion_storage);
+      GRPC_ERROR_REF(error);
+      w->error = error;
+      w->phase = READY_TO_CALL_BACK;
       break;
-    case CALLING_BACK:
+    case READY_TO_CALL_BACK:
+      if (error != GRPC_ERROR_NONE) {
+        GPR_ASSERT(!due_to_completion);
+        GRPC_ERROR_UNREF(w->error);
+        GRPC_ERROR_REF(error);
+        w->error = error;
+      }
       w->phase = CALLING_BACK_AND_FINISHED;
+      grpc_cq_end_op(exec_ctx, w->cq, w->tag, w->error, finished_completion, w,
+                     &w->completion_storage);
       break;
     case CALLING_BACK_AND_FINISHED:
       GPR_UNREACHABLE_CODE(return );
-    case CALLED_BACK:
-      delete = 1;
       break;
   }
   gpr_mu_unlock(&w->mu);
 
-  if (delete) {
-    delete_state_watcher(exec_ctx, w);
-  }
-
   GRPC_ERROR_UNREF(error);
 }
 
@@ -179,6 +183,28 @@ static void timeout_complete(grpc_exec_ctx *exec_ctx, void *pw,
   partly_done(exec_ctx, pw, false, GRPC_ERROR_REF(error));
 }
 
+int grpc_channel_num_external_connectivity_watchers(grpc_channel *channel) {
+  grpc_channel_element *client_channel_elem =
+      grpc_channel_stack_last_element(grpc_channel_get_channel_stack(channel));
+  return grpc_client_channel_num_external_connectivity_watchers(
+      client_channel_elem);
+}
+
+typedef struct watcher_timer_init_arg {
+  state_watcher *w;
+  gpr_timespec deadline;
+} watcher_timer_init_arg;
+
+static void watcher_timer_init(grpc_exec_ctx *exec_ctx, void *arg,
+                               grpc_error *error_ignored) {
+  watcher_timer_init_arg *wa = (watcher_timer_init_arg *)arg;
+
+  grpc_timer_init(exec_ctx, &wa->w->alarm,
+                  gpr_convert_clock_type(wa->deadline, GPR_CLOCK_MONOTONIC),
+                  &wa->w->on_timeout, gpr_now(GPR_CLOCK_MONOTONIC));
+  gpr_free(wa);
+}
+
 void grpc_channel_watch_connectivity_state(
     grpc_channel *channel, grpc_connectivity_state last_observed_state,
     gpr_timespec deadline, grpc_completion_queue *cq, void *tag) {
@@ -208,16 +234,19 @@ void grpc_channel_watch_connectivity_state(
   w->cq = cq;
   w->tag = tag;
   w->channel = channel;
+  w->error = NULL;
 
-  grpc_timer_init(&exec_ctx, &w->alarm,
-                  gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
-                  &w->on_timeout, gpr_now(GPR_CLOCK_MONOTONIC));
+  watcher_timer_init_arg *wa = gpr_malloc(sizeof(watcher_timer_init_arg));
+  wa->w = w;
+  wa->deadline = deadline;
+  grpc_closure_init(&w->watcher_timer_init, watcher_timer_init, wa,
+                    grpc_schedule_on_exec_ctx);
 
   if (client_channel_elem->filter == &grpc_client_channel_filter) {
     GRPC_CHANNEL_INTERNAL_REF(channel, "watch_channel_connectivity");
-    grpc_client_channel_watch_connectivity_state(&exec_ctx, client_channel_elem,
-                                                 grpc_cq_pollset(cq), &w->state,
-                                                 &w->on_complete);
+    grpc_client_channel_watch_connectivity_state(
+        &exec_ctx, client_channel_elem, grpc_cq_pollset(cq), &w->state,
+        &w->on_complete, &w->watcher_timer_init);
   } else {
     abort();
   }
diff --git a/src/core/ext/filters/client_channel/client_channel.c b/src/core/ext/filters/client_channel/client_channel.c
index f2f27b9175..8cebbe9eca 100644
--- a/src/core/ext/filters/client_channel/client_channel.c
+++ b/src/core/ext/filters/client_channel/client_channel.c
@@ -167,6 +167,8 @@ static void *method_parameters_create_from_json(const grpc_json *json) {
   return value;
 }
 
+struct external_connectivity_watcher;
+
 /*************************************************************************
  * CHANNEL-WIDE FUNCTIONS
  */
@@ -204,6 +206,11 @@ typedef struct client_channel_channel_data {
   /** interested parties (owned) */
   grpc_pollset_set *interested_parties;
 
+  /* external_connectivity_watcher_list head is guarded by its own mutex, since
+   * counts need to be grabbed immediately without polling on a cq */
+  gpr_mu external_connectivity_watcher_list_mu;
+  struct external_connectivity_watcher *external_connectivity_watcher_list_head;
+
   /* the following properties are guarded by a mutex since API's require them
      to be instantaneously available */
   gpr_mu info_mu;
@@ -661,6 +668,12 @@ static grpc_error *cc_init_channel_elem(grpc_exec_ctx *exec_ctx,
   // Initialize data members.
   chand->combiner = grpc_combiner_create(NULL);
   gpr_mu_init(&chand->info_mu);
+  gpr_mu_init(&chand->external_connectivity_watcher_list_mu);
+
+  gpr_mu_lock(&chand->external_connectivity_watcher_list_mu);
+  chand->external_connectivity_watcher_list_head = NULL;
+  gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu);
+
   chand->owning_stack = args->channel_stack;
   grpc_closure_init(&chand->on_resolver_result_changed,
                     on_resolver_result_changed_locked, chand,
@@ -749,6 +762,7 @@ static void cc_destroy_channel_elem(grpc_exec_ctx *exec_ctx,
   grpc_pollset_set_destroy(exec_ctx, chand->interested_parties);
   GRPC_COMBINER_UNREF(exec_ctx, chand->combiner, "client_channel");
   gpr_mu_destroy(&chand->info_mu);
+  gpr_mu_destroy(&chand->external_connectivity_watcher_list_mu);
 }
 
 /*************************************************************************
@@ -1431,14 +1445,79 @@ grpc_connectivity_state grpc_client_channel_check_connectivity_state(
   return out;
 }
 
-typedef struct {
+typedef struct external_connectivity_watcher {
   channel_data *chand;
   grpc_pollset *pollset;
   grpc_closure *on_complete;
+  grpc_closure *watcher_timer_init;
   grpc_connectivity_state *state;
   grpc_closure my_closure;
+  struct external_connectivity_watcher *next;
 } external_connectivity_watcher;
 
+static external_connectivity_watcher *lookup_external_connectivity_watcher(
+    channel_data *chand, grpc_closure *on_complete) {
+  gpr_mu_lock(&chand->external_connectivity_watcher_list_mu);
+  external_connectivity_watcher *w =
+      chand->external_connectivity_watcher_list_head;
+  while (w != NULL && w->on_complete != on_complete) {
+    w = w->next;
+  }
+  gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu);
+  return w;
+}
+
+static void external_connectivity_watcher_list_append(
+    channel_data *chand, external_connectivity_watcher *w) {
+  GPR_ASSERT(!lookup_external_connectivity_watcher(chand, w->on_complete));
+
+  gpr_mu_lock(&w->chand->external_connectivity_watcher_list_mu);
+  GPR_ASSERT(!w->next);
+  w->next = chand->external_connectivity_watcher_list_head;
+  chand->external_connectivity_watcher_list_head = w;
+  gpr_mu_unlock(&w->chand->external_connectivity_watcher_list_mu);
+}
+
+static void external_connectivity_watcher_list_remove(
+    channel_data *chand, external_connectivity_watcher *too_remove) {
+  GPR_ASSERT(
+      lookup_external_connectivity_watcher(chand, too_remove->on_complete));
+  gpr_mu_lock(&chand->external_connectivity_watcher_list_mu);
+  if (too_remove == chand->external_connectivity_watcher_list_head) {
+    chand->external_connectivity_watcher_list_head = too_remove->next;
+    gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu);
+    return;
+  }
+  external_connectivity_watcher *w =
+      chand->external_connectivity_watcher_list_head;
+  while (w != NULL) {
+    if (w->next == too_remove) {
+      w->next = w->next->next;
+      gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu);
+      return;
+    }
+    w = w->next;
+  }
+  GPR_UNREACHABLE_CODE(return );
+}
+
+int grpc_client_channel_num_external_connectivity_watchers(
+    grpc_channel_element *elem) {
+  channel_data *chand = elem->channel_data;
+  int count = 0;
+
+  gpr_mu_lock(&chand->external_connectivity_watcher_list_mu);
+  external_connectivity_watcher *w =
+      chand->external_connectivity_watcher_list_head;
+  while (w != NULL) {
+    count++;
+    w = w->next;
+  }
+  gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu);
+
+  return count;
+}
+
 static void on_external_watch_complete(grpc_exec_ctx *exec_ctx, void *arg,
                                        grpc_error *error) {
   external_connectivity_watcher *w = arg;
@@ -1447,6 +1526,7 @@ static void on_external_watch_complete(grpc_exec_ctx *exec_ctx, void *arg,
                                w->pollset);
   GRPC_CHANNEL_STACK_UNREF(exec_ctx, w->chand->owning_stack,
                            "external_connectivity_watcher");
+  external_connectivity_watcher_list_remove(w->chand, w);
   gpr_free(w);
   grpc_closure_run(exec_ctx, follow_up, GRPC_ERROR_REF(error));
 }
@@ -1454,21 +1534,42 @@ static void on_external_watch_complete(grpc_exec_ctx *exec_ctx, void *arg,
 static void watch_connectivity_state_locked(grpc_exec_ctx *exec_ctx, void *arg,
                                             grpc_error *error_ignored) {
   external_connectivity_watcher *w = arg;
-  grpc_closure_init(&w->my_closure, on_external_watch_complete, w,
-                    grpc_schedule_on_exec_ctx);
-  grpc_connectivity_state_notify_on_state_change(
-      exec_ctx, &w->chand->state_tracker, w->state, &w->my_closure);
+  external_connectivity_watcher *found = NULL;
+  if (w->state != NULL) {
+    external_connectivity_watcher_list_append(w->chand, w);
+    grpc_closure_run(exec_ctx, w->watcher_timer_init, GRPC_ERROR_NONE);
+    grpc_closure_init(&w->my_closure, on_external_watch_complete, w,
+                      grpc_schedule_on_exec_ctx);
+    grpc_connectivity_state_notify_on_state_change(
+        exec_ctx, &w->chand->state_tracker, w->state, &w->my_closure);
+  } else {
+    GPR_ASSERT(w->watcher_timer_init == NULL);
+    found = lookup_external_connectivity_watcher(w->chand, w->on_complete);
+    if (found) {
+      GPR_ASSERT(found->on_complete == w->on_complete);
+      grpc_connectivity_state_notify_on_state_change(
+          exec_ctx, &found->chand->state_tracker, NULL, &found->my_closure);
+    }
+    grpc_pollset_set_del_pollset(exec_ctx, w->chand->interested_parties,
+                                 w->pollset);
+    GRPC_CHANNEL_STACK_UNREF(exec_ctx, w->chand->owning_stack,
+                             "external_connectivity_watcher");
+    gpr_free(w);
+  }
 }
 
 void grpc_client_channel_watch_connectivity_state(
     grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_pollset *pollset,
-    grpc_connectivity_state *state, grpc_closure *closure) {
+    grpc_connectivity_state *state, grpc_closure *closure,
+    grpc_closure *watcher_timer_init) {
   channel_data *chand = elem->channel_data;
-  external_connectivity_watcher *w = gpr_malloc(sizeof(*w));
+  external_connectivity_watcher *w = gpr_zalloc(sizeof(*w));
   w->chand = chand;
   w->pollset = pollset;
   w->on_complete = closure;
   w->state = state;
+  w->watcher_timer_init = watcher_timer_init;
+
   grpc_pollset_set_add_pollset(exec_ctx, chand->interested_parties, pollset);
   GRPC_CHANNEL_STACK_REF(w->chand->owning_stack,
                          "external_connectivity_watcher");
diff --git a/src/core/ext/filters/client_channel/client_channel.h b/src/core/ext/filters/client_channel/client_channel.h
index 8d2490ea55..356a7ab0c1 100644
--- a/src/core/ext/filters/client_channel/client_channel.h
+++ b/src/core/ext/filters/client_channel/client_channel.h
@@ -53,9 +53,13 @@ extern const grpc_channel_filter grpc_client_channel_filter;
 grpc_connectivity_state grpc_client_channel_check_connectivity_state(
     grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, int try_to_connect);
 
+int grpc_client_channel_num_external_connectivity_watchers(
+    grpc_channel_element *elem);
+
 void grpc_client_channel_watch_connectivity_state(
     grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_pollset *pollset,
-    grpc_connectivity_state *state, grpc_closure *on_complete);
+    grpc_connectivity_state *state, grpc_closure *on_complete,
+    grpc_closure *watcher_timer_init);
 
 /* Debug helper: pull the subchannel call from a call stack element */
 grpc_subchannel_call *grpc_client_channel_get_subchannel_call(
diff --git a/src/csharp/Grpc.Auth/Grpc.Auth.csproj b/src/csharp/Grpc.Auth/Grpc.Auth.csproj
index 6ac25aa1f0..188ddb95b9 100755
--- a/src/csharp/Grpc.Auth/Grpc.Auth.csproj
+++ b/src/csharp/Grpc.Auth/Grpc.Auth.csproj
@@ -16,6 +16,8 @@
     <PackageProjectUrl>https://github.com/grpc/grpc</PackageProjectUrl>
     <PackageLicenseUrl>https://github.com/grpc/grpc/blob/master/LICENSE</PackageLicenseUrl>
     <NetStandardImplicitPackageVersion Condition=" '$(TargetFramework)' == 'netstandard1.5' ">1.6.0</NetStandardImplicitPackageVersion>
+    <IncludeSymbols>true</IncludeSymbols>
+    <IncludeSource>true</IncludeSource>
   </PropertyGroup>
 
   <ItemGroup>
@@ -23,7 +25,9 @@
   </ItemGroup>
 
   <ItemGroup>
-    <ProjectReference Include="../Grpc.Core/Grpc.Core.csproj" />
+    <ProjectReference Include="../Grpc.Core/Grpc.Core.csproj">
+      <PrivateAssets>None</PrivateAssets>
+    </ProjectReference>
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/csharp/Grpc.Core.Testing/Grpc.Core.Testing.csproj b/src/csharp/Grpc.Core.Testing/Grpc.Core.Testing.csproj
index f4dd5105fc..45ec874322 100755
--- a/src/csharp/Grpc.Core.Testing/Grpc.Core.Testing.csproj
+++ b/src/csharp/Grpc.Core.Testing/Grpc.Core.Testing.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <Import Project="..\Grpc.Core\Version.csproj.include" />
   <Import Project="..\Grpc.Core\Common.csproj.include" />
@@ -16,6 +16,8 @@
     <PackageProjectUrl>https://github.com/grpc/grpc</PackageProjectUrl>
     <PackageLicenseUrl>https://github.com/grpc/grpc/blob/master/LICENSE</PackageLicenseUrl>
     <NetStandardImplicitPackageVersion Condition=" '$(TargetFramework)' == 'netstandard1.5' ">1.6.0</NetStandardImplicitPackageVersion>
+    <IncludeSymbols>true</IncludeSymbols>
+    <IncludeSource>true</IncludeSource>
   </PropertyGroup>
 
   <ItemGroup>
@@ -23,7 +25,9 @@
   </ItemGroup>
 
   <ItemGroup>
-    <ProjectReference Include="../Grpc.Core/Grpc.Core.csproj" />
+    <ProjectReference Include="../Grpc.Core/Grpc.Core.csproj">
+      <PrivateAssets>None</PrivateAssets>
+    </ProjectReference>
   </ItemGroup>
 
   <ItemGroup Condition=" '$(TargetFramework)' == 'net45' ">
diff --git a/src/csharp/Grpc.Core/Channel.cs b/src/csharp/Grpc.Core/Channel.cs
index 4f29c35b32..51ae11fbde 100644
--- a/src/csharp/Grpc.Core/Channel.cs
+++ b/src/csharp/Grpc.Core/Channel.cs
@@ -59,6 +59,8 @@ namespace Grpc.Core
         readonly ChannelSafeHandle handle;
         readonly Dictionary<string, ChannelOption> options;
 
+        readonly Task connectivityWatcherTask;
+
         bool shutdownRequested;
 
         /// <summary>
@@ -99,6 +101,9 @@ namespace Grpc.Core
                     this.handle = ChannelSafeHandle.CreateInsecure(target, nativeChannelArgs);
                 }
             }
+            // TODO(jtattermusch): Workaround for https://github.com/GoogleCloudPlatform/google-cloud-dotnet/issues/822.
+            // Remove once retries are supported in C core
+            this.connectivityWatcherTask = RunConnectivityWatcherAsync();
             GrpcEnvironment.RegisterChannel(this);
         }
 
@@ -244,7 +249,7 @@ namespace Grpc.Core
 
             handle.Dispose();
 
-            await GrpcEnvironment.ReleaseAsync().ConfigureAwait(false);
+            await Task.WhenAll(GrpcEnvironment.ReleaseAsync(), connectivityWatcherTask).ConfigureAwait(false);
         }
 
         internal ChannelSafeHandle Handle
@@ -299,6 +304,40 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Constantly Watches channel connectivity status to work around https://github.com/GoogleCloudPlatform/google-cloud-dotnet/issues/822
+        /// </summary>
+        private async Task RunConnectivityWatcherAsync()
+        {
+            try
+            {
+                var lastState = State;
+                while (lastState != ChannelState.Shutdown)
+                {
+                    lock (myLock)
+                    {
+                        if (shutdownRequested)
+                        {
+                            break;
+                        }
+                    }
+
+                    try
+                    {
+                        await WaitForStateChangedAsync(lastState, DateTime.UtcNow.AddSeconds(1)).ConfigureAwait(false);
+                    }
+                    catch (TaskCanceledException)
+                    {
+                        // ignore timeout
+                    }
+                    lastState = State;
+                }
+            }
+            catch (ObjectDisposedException) {
+                // during shutdown, channel is going to be disposed.
+            }
+        }
+
         private static void EnsureUserAgentChannelOption(Dictionary<string, ChannelOption> options)
         {
             var key = ChannelOptions.PrimaryUserAgentString;
diff --git a/src/csharp/Grpc.Core/Grpc.Core.csproj b/src/csharp/Grpc.Core/Grpc.Core.csproj
index c0865001a8..ae0d8b2c8d 100755
--- a/src/csharp/Grpc.Core/Grpc.Core.csproj
+++ b/src/csharp/Grpc.Core/Grpc.Core.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <Import Project="Version.csproj.include" />
   <Import Project="Common.csproj.include" />
@@ -15,6 +15,8 @@
     <PackageProjectUrl>https://github.com/grpc/grpc</PackageProjectUrl>
     <PackageLicenseUrl>https://github.com/grpc/grpc/blob/master/LICENSE</PackageLicenseUrl>
     <NetStandardImplicitPackageVersion Condition=" '$(TargetFramework)' == 'netstandard1.5' ">1.6.0</NetStandardImplicitPackageVersion>
+    <IncludeSymbols>true</IncludeSymbols>
+    <IncludeSource>true</IncludeSource>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/csharp/Grpc.HealthCheck/Grpc.HealthCheck.csproj b/src/csharp/Grpc.HealthCheck/Grpc.HealthCheck.csproj
index eac6e1fc95..c3791a4e6b 100755
--- a/src/csharp/Grpc.HealthCheck/Grpc.HealthCheck.csproj
+++ b/src/csharp/Grpc.HealthCheck/Grpc.HealthCheck.csproj
@@ -15,6 +15,8 @@
     <PackageProjectUrl>https://github.com/grpc/grpc</PackageProjectUrl>
     <PackageLicenseUrl>https://github.com/grpc/grpc/blob/master/LICENSE</PackageLicenseUrl>
     <NetStandardImplicitPackageVersion Condition=" '$(TargetFramework)' == 'netstandard1.5' ">1.6.0</NetStandardImplicitPackageVersion>
+    <IncludeSymbols>true</IncludeSymbols>
+    <IncludeSource>true</IncludeSource>
   </PropertyGroup>
 
   <ItemGroup>
@@ -22,7 +24,9 @@
   </ItemGroup>
 
   <ItemGroup>
-    <ProjectReference Include="../Grpc.Core/Grpc.Core.csproj" />
+    <ProjectReference Include="../Grpc.Core/Grpc.Core.csproj">
+      <PrivateAssets>None</PrivateAssets>
+    </ProjectReference>
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/csharp/Grpc.Reflection/Grpc.Reflection.csproj b/src/csharp/Grpc.Reflection/Grpc.Reflection.csproj
index 70bfcc89c5..3a07555248 100755
--- a/src/csharp/Grpc.Reflection/Grpc.Reflection.csproj
+++ b/src/csharp/Grpc.Reflection/Grpc.Reflection.csproj
@@ -15,6 +15,8 @@
     <PackageProjectUrl>https://github.com/grpc/grpc</PackageProjectUrl>
     <PackageLicenseUrl>https://github.com/grpc/grpc/blob/master/LICENSE</PackageLicenseUrl>
     <NetStandardImplicitPackageVersion Condition=" '$(TargetFramework)' == 'netstandard1.5' ">1.6.0</NetStandardImplicitPackageVersion>
+    <IncludeSymbols>true</IncludeSymbols>
+    <IncludeSource>true</IncludeSource>
   </PropertyGroup>
 
   <ItemGroup>
@@ -22,7 +24,9 @@
   </ItemGroup>
 
   <ItemGroup>
-    <ProjectReference Include="../Grpc.Core/Grpc.Core.csproj" />
+    <ProjectReference Include="../Grpc.Core/Grpc.Core.csproj">
+      <PrivateAssets>None</PrivateAssets>
+    </ProjectReference>
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/csharp/build_packages_dotnetcli.bat b/src/csharp/build_packages_dotnetcli.bat
index d823942be5..aa8a8d3b17 100755
--- a/src/csharp/build_packages_dotnetcli.bat
+++ b/src/csharp/build_packages_dotnetcli.bat
@@ -51,11 +51,11 @@ powershell -Command "cp -r ..\..\platform=*\artifacts\protoc_* protoc_plugins"
 @rem To be able to build, we also need to put grpc_csharp_ext to its normal location
 xcopy /Y /I nativelibs\csharp_ext_windows_x64\grpc_csharp_ext.dll ..\..\cmake\build\x64\Release\
 
-%DOTNET% pack --configuration Release --include-symbols --include-source Grpc.Core --output ..\..\..\artifacts || goto :error
-%DOTNET% pack --configuration Release --include-symbols --include-source Grpc.Core.Testing --output ..\..\..\artifacts || goto :error
-%DOTNET% pack --configuration Release --include-symbols --include-source Grpc.Auth --output ..\..\..\artifacts || goto :error
-%DOTNET% pack --configuration Release --include-symbols --include-source Grpc.HealthCheck --output ..\..\..\artifacts || goto :error
-%DOTNET% pack --configuration Release --include-symbols --include-source Grpc.Reflection --output ..\..\..\artifacts || goto :error
+%DOTNET% pack --configuration Release Grpc.Core --output ..\..\..\artifacts || goto :error
+%DOTNET% pack --configuration Release Grpc.Core.Testing --output ..\..\..\artifacts || goto :error
+%DOTNET% pack --configuration Release Grpc.Auth --output ..\..\..\artifacts || goto :error
+%DOTNET% pack --configuration Release Grpc.HealthCheck --output ..\..\..\artifacts || goto :error
+%DOTNET% pack --configuration Release Grpc.Reflection --output ..\..\..\artifacts || goto :error
 
 %NUGET% pack Grpc.nuspec -Version %VERSION% -OutputDirectory ..\..\artifacts || goto :error
 %NUGET% pack Grpc.Tools.nuspec -Version %VERSION% -OutputDirectory ..\..\artifacts
diff --git a/src/csharp/build_packages_dotnetcli.sh b/src/csharp/build_packages_dotnetcli.sh
index f79c97fbbc..d33923845c 100755
--- a/src/csharp/build_packages_dotnetcli.sh
+++ b/src/csharp/build_packages_dotnetcli.sh
@@ -48,11 +48,11 @@ dotnet restore Grpc.sln
 mkdir -p ../../libs/opt
 cp nativelibs/csharp_ext_linux_x64/libgrpc_csharp_ext.so ../../libs/opt
 
-dotnet pack --configuration Release --include-symbols --include-source Grpc.Core --output ../../../artifacts
-dotnet pack --configuration Release --include-symbols --include-source Grpc.Core.Testing --output ../../../artifacts
-dotnet pack --configuration Release --include-symbols --include-source Grpc.Auth --output ../../../artifacts
-dotnet pack --configuration Release --include-symbols --include-source Grpc.HealthCheck --output ../../../artifacts
-dotnet pack --configuration Release --include-symbols --include-source Grpc.Reflection --output ../../../artifacts
+dotnet pack --configuration Release Grpc.Core --output ../../../artifacts
+dotnet pack --configuration Release Grpc.Core.Testing --output ../../../artifacts
+dotnet pack --configuration Release Grpc.Auth --output ../../../artifacts
+dotnet pack --configuration Release Grpc.HealthCheck --output ../../../artifacts
+dotnet pack --configuration Release Grpc.Reflection --output ../../../artifacts
 
 nuget pack Grpc.nuspec -Version "1.4.0-dev" -OutputDirectory ../../artifacts
 nuget pack Grpc.Tools.nuspec -Version "1.4.0-dev" -OutputDirectory ../../artifacts
diff --git a/src/node/ext/call.cc b/src/node/ext/call.cc
index 49179ab359..9453000ad3 100644
--- a/src/node/ext/call.cc
+++ b/src/node/ext/call.cc
@@ -508,9 +508,14 @@ void Call::DestroyCall() {
 }
 
 Call::Call(grpc_call *call)
-    : wrapped_call(call), pending_batches(0), has_final_op_completed(false) {}
+    : wrapped_call(call), pending_batches(0), has_final_op_completed(false) {
+  peer = grpc_call_get_peer(call);
+}
 
-Call::~Call() { DestroyCall(); }
+Call::~Call() {
+  DestroyCall();
+  gpr_free(peer);
+}
 
 void Call::Init(Local<Object> exports) {
   HandleScope scope;
@@ -662,6 +667,16 @@ NAN_METHOD(Call::StartBatch) {
   }
   Local<Function> callback_func = info[1].As<Function>();
   Call *call = ObjectWrap::Unwrap<Call>(info.This());
+  if (call->wrapped_call == NULL) {
+    /* This implies that the call has completed and has been destroyed. To
+     * emulate
+     * previous behavior, we should call the callback immediately with an error,
+     * as though the batch had failed in core */
+    Local<Value> argv[] = {
+        Nan::Error("The async function failed because the call has completed")};
+    Nan::Call(callback_func, Nan::New<Object>(), 1, argv);
+    return;
+  }
   Local<Object> obj = Nan::To<Object>(info[0]).ToLocalChecked();
   Local<Array> keys = Nan::GetOwnPropertyNames(obj).ToLocalChecked();
   size_t nops = keys->Length();
@@ -727,6 +742,11 @@ NAN_METHOD(Call::Cancel) {
     return Nan::ThrowTypeError("cancel can only be called on Call objects");
   }
   Call *call = ObjectWrap::Unwrap<Call>(info.This());
+  if (call->wrapped_call == NULL) {
+    /* Cancel is supposed to be idempotent. If the call has already finished,
+     * cancel should just complete silently */
+    return;
+  }
   grpc_call_error error = grpc_call_cancel(call->wrapped_call, NULL);
   if (error != GRPC_CALL_OK) {
     return Nan::ThrowError(nanErrorWithCode("cancel failed", error));
@@ -747,6 +767,11 @@ NAN_METHOD(Call::CancelWithStatus) {
         "cancelWithStatus's second argument must be a string");
   }
   Call *call = ObjectWrap::Unwrap<Call>(info.This());
+  if (call->wrapped_call == NULL) {
+    /* Cancel is supposed to be idempotent. If the call has already finished,
+     * cancel should just complete silently */
+    return;
+  }
   grpc_status_code code =
       static_cast<grpc_status_code>(Nan::To<uint32_t>(info[0]).FromJust());
   if (code == GRPC_STATUS_OK) {
@@ -763,9 +788,7 @@ NAN_METHOD(Call::GetPeer) {
     return Nan::ThrowTypeError("getPeer can only be called on Call objects");
   }
   Call *call = ObjectWrap::Unwrap<Call>(info.This());
-  char *peer = grpc_call_get_peer(call->wrapped_call);
-  Local<Value> peer_value = Nan::New(peer).ToLocalChecked();
-  gpr_free(peer);
+  Local<Value> peer_value = Nan::New(call->peer).ToLocalChecked();
   info.GetReturnValue().Set(peer_value);
 }
 
@@ -780,6 +803,10 @@ NAN_METHOD(Call::SetCredentials) {
         "setCredentials' first argument must be a CallCredentials");
   }
   Call *call = ObjectWrap::Unwrap<Call>(info.This());
+  if (call->wrapped_call == NULL) {
+    return Nan::ThrowError(
+        "Cannot set credentials on a call that has already started");
+  }
   CallCredentials *creds_object = ObjectWrap::Unwrap<CallCredentials>(
       Nan::To<Object>(info[0]).ToLocalChecked());
   grpc_call_credentials *creds = creds_object->GetWrappedCredentials();
diff --git a/src/node/ext/call.h b/src/node/ext/call.h
index 0bd24f56a9..8f751279e4 100644
--- a/src/node/ext/call.h
+++ b/src/node/ext/call.h
@@ -96,6 +96,7 @@ class Call : public Nan::ObjectWrap {
      call, this is GRPC_OP_RECV_STATUS_ON_CLIENT and for a server call, this
      is GRPC_OP_SEND_STATUS_FROM_SERVER */
   bool has_final_op_completed;
+  char *peer;
 };
 
 class Op {
diff --git a/src/node/src/client.js b/src/node/src/client.js
index cf4c104144..f59ac5c94c 100644
--- a/src/node/src/client.js
+++ b/src/node/src/client.js
@@ -147,6 +147,12 @@ function _write(chunk, encoding, callback) {
   /* jshint validthis: true */
   var batch = {};
   var message;
+  var self = this;
+  if (this.writeFailed) {
+    /* Once a write fails, just call the callback immediately to let the caller
+       flush any pending writes. */
+    setImmediate(callback);
+  }
   try {
     message = this.serialize(chunk);
   } catch (e) {
@@ -167,8 +173,10 @@ function _write(chunk, encoding, callback) {
   batch[grpc.opType.SEND_MESSAGE] = message;
   this.call.startBatch(batch, function(err, event) {
     if (err) {
-      // Something has gone wrong. Stop writing by failing to call callback
-      return;
+      /* Assume that the call is complete and that writing failed because a
+         status was received. In that case, set a flag to discard all future
+         writes */
+      self.writeFailed = true;
     }
     callback();
   });
diff --git a/src/node/test/common_test.js b/src/node/test/common_test.js
index b7c2c6a8d6..db80207e22 100644
--- a/src/node/test/common_test.js
+++ b/src/node/test/common_test.js
@@ -100,7 +100,6 @@ describe('Proto message long int serialize and deserialize', function() {
     var longNumDeserialize = deserializeCls(messages_proto.LongValues,
                                             num_options);
     var serialized = longSerialize({int_64: pos_value});
-    console.log(longDeserialize(serialized));
     assert.strictEqual(typeof longDeserialize(serialized).int_64, 'string');
     /* With the longsAsStrings option disabled, long values are represented as
      * objects with 3 keys: low, high, and unsigned */
diff --git a/src/node/test/surface_test.js b/src/node/test/surface_test.js
index 6f1c269267..f8eaf62aaf 100644
--- a/src/node/test/surface_test.js
+++ b/src/node/test/surface_test.js
@@ -1110,6 +1110,18 @@ describe('Other conditions', function() {
         done();
       });
     });
+    it('after the call has fully completed', function(done) {
+      var peer;
+      var call = client.unary({error: false}, function(err, data) {
+        assert.ifError(err);
+        setImmediate(function() {
+          assert.strictEqual(peer, call.getPeer());
+          done();
+        });
+      });
+      peer = call.getPeer();
+      assert.strictEqual(typeof peer, 'string');
+    });
   });
 });
 describe('Call propagation', function() {
@@ -1352,4 +1364,17 @@ describe('Cancelling surface client', function() {
     });
     call.cancel();
   });
+  it('Should be idempotent', function(done) {
+    var call = client.div({'divisor': 0, 'dividend': 0}, function(err, resp) {
+      assert.strictEqual(err.code, grpc.status.CANCELLED);
+      // Call asynchronously to try cancelling after call is fully completed
+      setImmediate(function() {
+        assert.doesNotThrow(function() {
+          call.cancel();
+        });
+        done();
+      });
+    });
+    call.cancel();
+  });
 });
diff --git a/src/python/grpcio/grpc/_channel.py b/src/python/grpcio/grpc/_channel.py
index 4316449ac6..012ed8ec81 100644
--- a/src/python/grpcio/grpc/_channel.py
+++ b/src/python/grpcio/grpc/_channel.py
@@ -786,7 +786,7 @@ def _channel_managed_call_management(state):
 class _ChannelConnectivityState(object):
 
     def __init__(self, channel):
-        self.lock = threading.Lock()
+        self.lock = threading.RLock()
         self.channel = channel
         self.polling = False
         self.connectivity = None
@@ -926,6 +926,11 @@ class Channel(grpc.Channel):
         self._call_state = _ChannelCallState(self._channel)
         self._connectivity_state = _ChannelConnectivityState(self._channel)
 
+        # TODO(https://github.com/grpc/grpc/issues/9884)
+        # Temporary work around UNAVAILABLE issues
+        # Remove this once c-core has retry support
+        _subscribe(self._connectivity_state, lambda *args: None, None)
+
     def subscribe(self, callback, try_to_connect=None):
         _subscribe(self._connectivity_state, callback, try_to_connect)
 
diff --git a/src/python/grpcio_tests/tests/tests.json b/src/python/grpcio_tests/tests/tests.json
index 9f7587faa6..126e8ac60d 100644
--- a/src/python/grpcio_tests/tests/tests.json
+++ b/src/python/grpcio_tests/tests/tests.json
@@ -32,6 +32,7 @@
   "unit._invocation_defects_test.InvocationDefectsTest",
   "unit._metadata_code_details_test.MetadataCodeDetailsTest",
   "unit._metadata_test.MetadataTest",
+  "unit._reconnect_test.ReconnectTest",
   "unit._resource_exhausted_test.ResourceExhaustedTest",
   "unit._rpc_test.RPCTest",
   "unit._sanity._sanity_test.Sanity",
diff --git a/src/python/grpcio_tests/tests/unit/_reconnect_test.py b/src/python/grpcio_tests/tests/unit/_reconnect_test.py
new file mode 100644
index 0000000000..6c316476b3
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_reconnect_test.py
@@ -0,0 +1,70 @@
+# Copyright 2017, 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.
+"""Tests that a channel will reconnect if a connection is dropped"""
+
+import unittest
+
+import grpc
+from grpc.framework.foundation import logging_pool
+
+from tests.unit.framework.common import test_constants
+
+_REQUEST = b'\x00\x00\x00'
+_RESPONSE = b'\x00\x00\x01'
+
+_UNARY_UNARY = '/test/UnaryUnary'
+
+
+def _handle_unary_unary(unused_request, unused_servicer_context):
+    return _RESPONSE
+
+
+class ReconnectTest(unittest.TestCase):
+
+    def test_reconnect(self):
+        server_pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+        handler = grpc.method_handlers_generic_handler('test', {
+            'UnaryUnary':
+            grpc.unary_unary_rpc_method_handler(_handle_unary_unary)
+        })
+        server = grpc.server(server_pool, (handler,))
+        port = server.add_insecure_port('[::]:0')
+        server.start()
+        channel = grpc.insecure_channel('localhost:%d' % port)
+        multi_callable = channel.unary_unary(_UNARY_UNARY)
+        self.assertEqual(_RESPONSE, multi_callable(_REQUEST))
+        server.stop(None)
+        server = grpc.server(server_pool, (handler,))
+        server.add_insecure_port('[::]:{}'.format(port))
+        server.start()
+        self.assertEqual(_RESPONSE, multi_callable(_REQUEST))
+
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)
diff --git a/src/ruby/end2end/channel_closing_driver.rb b/src/ruby/end2end/channel_closing_driver.rb
index d3e5373b0b..bed8c43405 100755
--- a/src/ruby/end2end/channel_closing_driver.rb
+++ b/src/ruby/end2end/channel_closing_driver.rb
@@ -61,6 +61,11 @@ def main
       'channel is closed while connectivity is watched'
   end
 
+  client_exit_code = $CHILD_STATUS
+  if client_exit_code != 0
+    fail "channel closing client failed, exit code #{client_exit_code}"
+  end
+
   server_runner.stop
 end
 
diff --git a/src/ruby/end2end/channel_state_driver.rb b/src/ruby/end2end/channel_state_driver.rb
index 80fb62899e..9910076dba 100755
--- a/src/ruby/end2end/channel_state_driver.rb
+++ b/src/ruby/end2end/channel_state_driver.rb
@@ -58,6 +58,9 @@ def main
            'It likely hangs when ended abruptly'
   end
 
+  # The interrupt in the child process should cause it to
+  # exit a non-zero status, so don't check it here.
+  # This test mainly tries to catch deadlock.
   server_runner.stop
 end
 
diff --git a/src/ruby/end2end/grpc_class_init_client.rb b/src/ruby/end2end/grpc_class_init_client.rb
index ee79292119..e73ca76850 100755
--- a/src/ruby/end2end/grpc_class_init_client.rb
+++ b/src/ruby/end2end/grpc_class_init_client.rb
@@ -34,44 +34,110 @@
 
 require_relative './end2end_common'
 
-def main
-  grpc_class = ''
-  OptionParser.new do |opts|
-    opts.on('--grpc_class=P', String) do |p|
-      grpc_class = p
+def construct_many(test_proc)
+  thds = []
+  4.times do
+    thds << Thread.new do
+      20.times do
+        test_proc.call
+      end
     end
-  end.parse!
+  end
+  20.times do
+    test_proc.call
+  end
+  thds.each(&:join)
+end
+
+def run_gc_stress_test(test_proc)
+  GC.disable
+  construct_many(test_proc)
 
-  test_proc = nil
+  GC.enable
+  construct_many(test_proc)
+
+  GC.start(full_mark: true, immediate_sweep: true)
+  construct_many(test_proc)
+end
+
+def run_concurrency_stress_test(test_proc)
+  100.times do
+    Thread.new do
+      test_proc.call
+    end
+  end
+
+  test_proc.call
+
+  fail 'exception thrown while child thread initing class'
+end
 
+# default (no gc_stress and no concurrency_stress)
+def run_default_test(test_proc)
+  thd = Thread.new do
+    test_proc.call
+  end
+  test_proc.call
+  thd.join
+end
+
+def get_test_proc(grpc_class)
   case grpc_class
   when 'channel'
-    test_proc = proc do
+    return proc do
       GRPC::Core::Channel.new('dummy_host', nil, :this_channel_is_insecure)
     end
   when 'server'
-    test_proc = proc do
+    return proc do
       GRPC::Core::Server.new({})
     end
   when 'channel_credentials'
-    test_proc = proc do
+    return proc do
       GRPC::Core::ChannelCredentials.new
     end
   when 'call_credentials'
-    test_proc = proc do
+    return proc do
       GRPC::Core::CallCredentials.new(proc { |noop| noop })
     end
   when 'compression_options'
-    test_proc = proc do
+    return proc do
       GRPC::Core::CompressionOptions.new
     end
   else
     fail "bad --grpc_class=#{grpc_class} param"
   end
+end
 
-  th = Thread.new { test_proc.call }
-  test_proc.call
-  th.join
+def main
+  grpc_class = ''
+  stress_test = ''
+  OptionParser.new do |opts|
+    opts.on('--grpc_class=P', String) do |p|
+      grpc_class = p
+    end
+    opts.on('--stress_test=P') do |p|
+      stress_test = p
+    end
+  end.parse!
+
+  test_proc = get_test_proc(grpc_class)
+
+  # the different test configs need to be ran
+  # in separate processes, since each one tests
+  # clean shutdown in a different way
+  case stress_test
+  when 'gc'
+    p 'run gc stress'
+    run_gc_stress_test(test_proc)
+  when 'concurrency'
+    p 'run concurrency stress'
+    run_concurrency_stress_test(test_proc)
+  when ''
+    p 'run default'
+    run_default_test(test_proc)
+  else
+    fail "bad --stress_test=#{stress_test} param"
+  end
 end
 
 main
diff --git a/src/ruby/end2end/grpc_class_init_driver.rb b/src/ruby/end2end/grpc_class_init_driver.rb
index 764d029f14..c65ed547c5 100755
--- a/src/ruby/end2end/grpc_class_init_driver.rb
+++ b/src/ruby/end2end/grpc_class_init_driver.rb
@@ -38,29 +38,40 @@ def main
                             call_credentials
                             compression_options )
 
-  native_grpc_classes.each do |grpc_class|
-    STDERR.puts 'start client'
-    this_dir = File.expand_path(File.dirname(__FILE__))
-    client_path = File.join(this_dir, 'grpc_class_init_client.rb')
-    client_pid = Process.spawn(RbConfig.ruby,
-                               client_path,
-                               "--grpc_class=#{grpc_class}")
-    begin
-      Timeout.timeout(10) do
-        Process.wait(client_pid)
+  # there is room for false positives in this test,
+  # do a few runs for each config
+  4.times do
+    native_grpc_classes.each do |grpc_class|
+      ['', 'gc', 'concurrency'].each do |stress_test_type|
+        STDERR.puts 'start client'
+        this_dir = File.expand_path(File.dirname(__FILE__))
+        client_path = File.join(this_dir, 'grpc_class_init_client.rb')
+        client_pid = Process.spawn(RbConfig.ruby,
+                                   client_path,
+                                   "--grpc_class=#{grpc_class}",
+                                   "--stress_test=#{stress_test_type}")
+        begin
+          Timeout.timeout(10) do
+            Process.wait(client_pid)
+          end
+        rescue Timeout::Error
+          STDERR.puts "timeout waiting for client pid #{client_pid}"
+          Process.kill('SIGKILL', client_pid)
+          Process.wait(client_pid)
+          STDERR.puts 'killed client child'
+          raise 'Timed out waiting for client process. ' \
+            'It likely hangs when the first constructed gRPC object has ' \
+            "type: #{grpc_class}"
+        end
+
+        client_exit_code = $CHILD_STATUS
+        # concurrency stress test type is expected to exit with a
+        # non-zero status due to an exception being raised
+        if client_exit_code != 0 && stress_test_type != 'concurrency'
+          fail "client failed, exit code #{client_exit_code}"
+        end
       end
-    rescue Timeout::Error
-      STDERR.puts "timeout waiting for client pid #{client_pid}"
-      Process.kill('SIGKILL', client_pid)
-      Process.wait(client_pid)
-      STDERR.puts 'killed client child'
-      raise 'Timed out waiting for client process. ' \
-        'It likely hangs when the first constructed gRPC object has ' \
-        "type: #{grpc_class}"
     end
-
-    client_exit_code = $CHILD_STATUS
-    fail "client failed, exit code #{client_exit_code}" if client_exit_code != 0
   end
 end
 
diff --git a/src/ruby/end2end/multiple_killed_watching_threads_driver.rb b/src/ruby/end2end/multiple_killed_watching_threads_driver.rb
new file mode 100755
index 0000000000..206ec8e801
--- /dev/null
+++ b/src/ruby/end2end/multiple_killed_watching_threads_driver.rb
@@ -0,0 +1,63 @@
+#!/usr/bin/env ruby
+
+# 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_relative './end2end_common'
+
+Thread.abort_on_exception = true
+
+include GRPC::Core::ConnectivityStates
+
+def watch_state(ch)
+  thd = Thread.new do
+    state = ch.connectivity_state(false)
+    fail "non-idle state: #{state}" unless state == IDLE
+    ch.watch_connectivity_state(IDLE, Time.now + 360)
+  end
+  sleep 0.1
+  thd.kill
+end
+
+def main
+  channels = []
+  10.times do
+    ch = GRPC::Core::Channel.new('dummy_host',
+                                 nil, :this_channel_is_insecure)
+    watch_state(ch)
+    channels << ch
+  end
+
+  # checking state should still be safe to call
+  channels.each do |c|
+    fail unless c.connectivity_state(false) == FATAL_FAILURE
+  end
+end
+
+main
diff --git a/src/ruby/end2end/sig_int_during_channel_watch_client.rb b/src/ruby/end2end/sig_int_during_channel_watch_client.rb
index 389fc5ba33..0c6a374925 100755
--- a/src/ruby/end2end/sig_int_during_channel_watch_client.rb
+++ b/src/ruby/end2end/sig_int_during_channel_watch_client.rb
@@ -46,6 +46,8 @@ def main
     end
   end.parse!
 
+  trap('SIGINT') { exit 0 }
+
   thd = Thread.new do
     child_thread_channel = GRPC::Core::Channel.new("localhost:#{server_port}",
                                                    {},
diff --git a/src/ruby/end2end/sig_int_during_channel_watch_driver.rb b/src/ruby/end2end/sig_int_during_channel_watch_driver.rb
index 670cda0919..79a8c133fa 100755
--- a/src/ruby/end2end/sig_int_during_channel_watch_driver.rb
+++ b/src/ruby/end2end/sig_int_during_channel_watch_driver.rb
@@ -63,6 +63,11 @@ def main
       'SIGINT is sent while there is an active connectivity_state call'
   end
 
+  client_exit_code = $CHILD_STATUS
+  if client_exit_code != 0
+    fail "sig_int_during_channel_watch_client failed: #{client_exit_code}"
+  end
+
   server_runner.stop
 end
 
diff --git a/src/ruby/ext/grpc/rb_channel.c b/src/ruby/ext/grpc/rb_channel.c
index a802183726..f65388448a 100644
--- a/src/ruby/ext/grpc/rb_channel.c
+++ b/src/ruby/ext/grpc/rb_channel.c
@@ -68,29 +68,53 @@ static VALUE grpc_rb_cChannel = Qnil;
 /* Used during the conversion of a hash to channel args during channel setup */
 static VALUE grpc_rb_cChannelArgs;
 
+typedef struct bg_watched_channel {
+  grpc_channel *channel;
+  // these fields must only be accessed under global_connection_polling_mu
+  struct bg_watched_channel *next;
+  int channel_destroyed;
+  int refcount;
+} bg_watched_channel;
+
 /* grpc_rb_channel wraps a grpc_channel. */
 typedef struct grpc_rb_channel {
   VALUE credentials;
 
-  /* The actual channel */
-  grpc_channel *wrapped;
-  int request_safe_destroy;
-  int safe_to_destroy;
-  grpc_connectivity_state current_connectivity_state;
-
-  int mu_init_done;
-  int abort_watch_connectivity_state;
-  gpr_mu channel_mu;
-  gpr_cv channel_cv;
+  /* The actual channel (protected in a wrapper to tell when it's safe to
+   * destroy) */
+  bg_watched_channel *bg_wrapped;
 } grpc_rb_channel;
 
-/* Forward declarations of functions involved in temporary fix to
- * https://github.com/grpc/grpc/issues/9941 */
+typedef enum { CONTINUOUS_WATCH, WATCH_STATE_API } watch_state_op_type;
+
+typedef struct watch_state_op {
+  watch_state_op_type op_type;
+  // from event.success
+  union {
+    struct {
+      int success;
+      // has been called back due to a cq next call
+      int called_back;
+    } api_callback_args;
+    struct {
+      bg_watched_channel *bg;
+    } continuous_watch_callback_args;
+  } op;
+} watch_state_op;
+
+static bg_watched_channel *bg_watched_channel_list_head = NULL;
+
 static void grpc_rb_channel_try_register_connection_polling(
-    grpc_rb_channel *wrapper);
-static void grpc_rb_channel_safe_destroy(grpc_rb_channel *wrapper);
+    bg_watched_channel *bg);
 static void *wait_until_channel_polling_thread_started_no_gil(void *);
 static void wait_until_channel_polling_thread_started_unblocking_func(void *);
+static void *channel_init_try_register_connection_polling_without_gil(
+    void *arg);
+
+typedef struct channel_init_try_register_stack {
+  grpc_channel *channel;
+  grpc_rb_channel *wrapper;
+} channel_init_try_register_stack;
 
 static grpc_completion_queue *channel_polling_cq;
 static gpr_mu global_connection_polling_mu;
@@ -98,6 +122,42 @@ static gpr_cv global_connection_polling_cv;
 static int abort_channel_polling = 0;
 static int channel_polling_thread_started = 0;
 
+static int bg_watched_channel_list_lookup(bg_watched_channel *bg);
+static bg_watched_channel *bg_watched_channel_list_create_and_add(
+    grpc_channel *channel);
+static void bg_watched_channel_list_free_and_remove(bg_watched_channel *bg);
+static void run_poll_channels_loop_unblocking_func(void *arg);
+
+// Needs to be called under global_connection_polling_mu
+static void grpc_rb_channel_watch_connection_state_op_complete(
+    watch_state_op *op, int success) {
+  GPR_ASSERT(!op->op.api_callback_args.called_back);
+  op->op.api_callback_args.called_back = 1;
+  op->op.api_callback_args.success = success;
+  // wake up the watch API call thats waiting on this op
+  gpr_cv_broadcast(&global_connection_polling_cv);
+}
+
+/* Avoids destroying a channel twice. */
+static void grpc_rb_channel_safe_destroy(bg_watched_channel *bg) {
+  gpr_mu_lock(&global_connection_polling_mu);
+  GPR_ASSERT(bg_watched_channel_list_lookup(bg));
+  if (!bg->channel_destroyed) {
+    grpc_channel_destroy(bg->channel);
+    bg->channel_destroyed = 1;
+  }
+  bg->refcount--;
+  if (bg->refcount == 0) {
+    bg_watched_channel_list_free_and_remove(bg);
+  }
+  gpr_mu_unlock(&global_connection_polling_mu);
+}
+
+static void *channel_safe_destroy_without_gil(void *arg) {
+  grpc_rb_channel_safe_destroy((bg_watched_channel *)arg);
+  return NULL;
+}
+
 /* Destroys Channel instances. */
 static void grpc_rb_channel_free(void *p) {
   grpc_rb_channel *ch = NULL;
@@ -106,14 +166,13 @@ static void grpc_rb_channel_free(void *p) {
   };
   ch = (grpc_rb_channel *)p;
 
-  if (ch->wrapped != NULL) {
-    grpc_rb_channel_safe_destroy(ch);
-    ch->wrapped = NULL;
-  }
-
-  if (ch->mu_init_done) {
-    gpr_mu_destroy(&ch->channel_mu);
-    gpr_cv_destroy(&ch->channel_cv);
+  if (ch->bg_wrapped != NULL) {
+    /* assumption made here: it's ok to directly gpr_mu_lock the global
+     * connection polling mutex becuse we're in a finalizer,
+     * and we can count on this thread to not be interrupted or
+     * yield the gil. */
+    grpc_rb_channel_safe_destroy(ch->bg_wrapped);
+    ch->bg_wrapped = NULL;
   }
 
   xfree(p);
@@ -146,7 +205,7 @@ static rb_data_type_t grpc_channel_data_type = {"grpc_channel",
 /* Allocates grpc_rb_channel instances. */
 static VALUE grpc_rb_channel_alloc(VALUE cls) {
   grpc_rb_channel *wrapper = ALLOC(grpc_rb_channel);
-  wrapper->wrapped = NULL;
+  wrapper->bg_wrapped = NULL;
   wrapper->credentials = Qnil;
   return TypedData_Wrap_Struct(cls, &grpc_channel_data_type, wrapper);
 }
@@ -168,18 +227,21 @@ static VALUE grpc_rb_channel_init(int argc, VALUE *argv, VALUE self) {
   grpc_channel_credentials *creds = NULL;
   char *target_chars = NULL;
   grpc_channel_args args;
+  channel_init_try_register_stack stack;
+  int stop_waiting_for_thread_start = 0;
   MEMZERO(&args, grpc_channel_args, 1);
 
   grpc_ruby_once_init();
   rb_thread_call_without_gvl(
-      wait_until_channel_polling_thread_started_no_gil, NULL,
-      wait_until_channel_polling_thread_started_unblocking_func, NULL);
+      wait_until_channel_polling_thread_started_no_gil,
+      &stop_waiting_for_thread_start,
+      wait_until_channel_polling_thread_started_unblocking_func,
+      &stop_waiting_for_thread_start);
 
   /* "3" == 3 mandatory args */
   rb_scan_args(argc, argv, "3", &target, &channel_args, &credentials);
 
   TypedData_Get_Struct(self, grpc_rb_channel, &grpc_channel_data_type, wrapper);
-  wrapper->mu_init_done = 0;
   target_chars = StringValueCStr(target);
   grpc_rb_hash_convert_to_channel_args(channel_args, &args);
   if (TYPE(credentials) == T_SYMBOL) {
@@ -196,24 +258,11 @@ static VALUE grpc_rb_channel_init(int argc, VALUE *argv, VALUE self) {
   }
 
   GPR_ASSERT(ch);
-
-  wrapper->wrapped = ch;
-
-  gpr_mu_init(&wrapper->channel_mu);
-  gpr_cv_init(&wrapper->channel_cv);
-  wrapper->mu_init_done = 1;
-
-  gpr_mu_lock(&wrapper->channel_mu);
-  wrapper->abort_watch_connectivity_state = 0;
-  wrapper->current_connectivity_state =
-      grpc_channel_check_connectivity_state(wrapper->wrapped, 0);
-  wrapper->safe_to_destroy = 0;
-  wrapper->request_safe_destroy = 0;
-
-  gpr_cv_broadcast(&wrapper->channel_cv);
-  gpr_mu_unlock(&wrapper->channel_mu);
-
-  grpc_rb_channel_try_register_connection_polling(wrapper);
+  stack.channel = ch;
+  stack.wrapper = wrapper;
+  rb_thread_call_without_gvl(
+      channel_init_try_register_connection_polling_without_gil, &stack, NULL,
+      NULL);
 
   if (args.args != NULL) {
     xfree(args.args); /* Allocated by grpc_rb_hash_convert_to_channel_args */
@@ -224,10 +273,31 @@ static VALUE grpc_rb_channel_init(int argc, VALUE *argv, VALUE self) {
     return Qnil;
   }
   rb_ivar_set(self, id_target, target);
-  wrapper->wrapped = ch;
   return self;
 }
 
+typedef struct get_state_stack {
+  bg_watched_channel *bg;
+  int try_to_connect;
+  int out;
+} get_state_stack;
+
+static void *get_state_without_gil(void *arg) {
+  get_state_stack *stack = (get_state_stack *)arg;
+
+  gpr_mu_lock(&global_connection_polling_mu);
+  GPR_ASSERT(abort_channel_polling || channel_polling_thread_started);
+  if (stack->bg->channel_destroyed) {
+    stack->out = GRPC_CHANNEL_SHUTDOWN;
+  } else {
+    stack->out = grpc_channel_check_connectivity_state(stack->bg->channel,
+                                                       stack->try_to_connect);
+  }
+  gpr_mu_unlock(&global_connection_polling_mu);
+
+  return NULL;
+}
+
 /*
   call-seq:
     ch.connectivity_state       -> state
@@ -240,59 +310,69 @@ static VALUE grpc_rb_channel_init(int argc, VALUE *argv, VALUE self) {
 static VALUE grpc_rb_channel_get_connectivity_state(int argc, VALUE *argv,
                                                     VALUE self) {
   VALUE try_to_connect_param = Qfalse;
-  int grpc_try_to_connect = 0;
   grpc_rb_channel *wrapper = NULL;
-  grpc_channel *ch = NULL;
+  get_state_stack stack;
 
   /* "01" == 0 mandatory args, 1 (try_to_connect) is optional */
   rb_scan_args(argc, argv, "01", &try_to_connect_param);
-  grpc_try_to_connect = RTEST(try_to_connect_param) ? 1 : 0;
 
   TypedData_Get_Struct(self, grpc_rb_channel, &grpc_channel_data_type, wrapper);
-  ch = wrapper->wrapped;
-  if (ch == NULL) {
+  if (wrapper->bg_wrapped == NULL) {
     rb_raise(rb_eRuntimeError, "closed!");
     return Qnil;
   }
-  return LONG2NUM(grpc_channel_check_connectivity_state(wrapper->wrapped,
-                                                        grpc_try_to_connect));
+
+  stack.bg = wrapper->bg_wrapped;
+  stack.try_to_connect = RTEST(try_to_connect_param) ? 1 : 0;
+  rb_thread_call_without_gvl(get_state_without_gil, &stack, NULL, NULL);
+
+  return LONG2NUM(stack.out);
 }
 
 typedef struct watch_state_stack {
-  grpc_rb_channel *wrapper;
+  grpc_channel *channel;
   gpr_timespec deadline;
   int last_state;
 } watch_state_stack;
 
-static void *watch_channel_state_without_gvl(void *arg) {
+static void *wait_for_watch_state_op_complete_without_gvl(void *arg) {
   watch_state_stack *stack = (watch_state_stack *)arg;
-  gpr_timespec deadline = stack->deadline;
-  grpc_rb_channel *wrapper = stack->wrapper;
-  int last_state = stack->last_state;
-  void *return_value = (void *)0;
+  watch_state_op *op = NULL;
+  void *success = (void *)0;
 
-  gpr_mu_lock(&wrapper->channel_mu);
-  while (wrapper->current_connectivity_state == last_state &&
-         !wrapper->request_safe_destroy && !wrapper->safe_to_destroy &&
-         !wrapper->abort_watch_connectivity_state &&
-         gpr_time_cmp(deadline, gpr_now(GPR_CLOCK_REALTIME)) > 0) {
-    gpr_cv_wait(&wrapper->channel_cv, &wrapper->channel_mu, deadline);
+  gpr_mu_lock(&global_connection_polling_mu);
+  // its unsafe to do a "watch" after "channel polling abort" because the cq has
+  // been shut down.
+  if (abort_channel_polling) {
+    gpr_mu_unlock(&global_connection_polling_mu);
+    return (void *)0;
   }
-  if (wrapper->current_connectivity_state != last_state) {
-    return_value = (void *)1;
+  op = gpr_zalloc(sizeof(watch_state_op));
+  op->op_type = WATCH_STATE_API;
+  grpc_channel_watch_connectivity_state(stack->channel, stack->last_state,
+                                        stack->deadline, channel_polling_cq,
+                                        op);
+
+  while (!op->op.api_callback_args.called_back) {
+    gpr_cv_wait(&global_connection_polling_cv, &global_connection_polling_mu,
+                gpr_inf_future(GPR_CLOCK_REALTIME));
   }
-  gpr_mu_unlock(&wrapper->channel_mu);
+  if (op->op.api_callback_args.success) {
+    success = (void *)1;
+  }
+  gpr_free(op);
+  gpr_mu_unlock(&global_connection_polling_mu);
 
-  return return_value;
+  return success;
 }
-
-static void watch_channel_state_unblocking_func(void *arg) {
-  grpc_rb_channel *wrapper = (grpc_rb_channel *)arg;
-  gpr_log(GPR_DEBUG, "GRPC_RUBY: watch channel state unblocking func called");
-  gpr_mu_lock(&wrapper->channel_mu);
-  wrapper->abort_watch_connectivity_state = 1;
-  gpr_cv_broadcast(&wrapper->channel_cv);
-  gpr_mu_unlock(&wrapper->channel_mu);
+static void wait_for_watch_state_op_complete_unblocking_func(void *arg) {
+  bg_watched_channel *bg = (bg_watched_channel *)arg;
+  gpr_mu_lock(&global_connection_polling_mu);
+  if (!bg->channel_destroyed) {
+    grpc_channel_destroy(bg->channel);
+    bg->channel_destroyed = 1;
+  }
+  gpr_mu_unlock(&global_connection_polling_mu);
 }
 
 /* Wait until the channel's connectivity state becomes different from
@@ -307,11 +387,11 @@ static VALUE grpc_rb_channel_watch_connectivity_state(VALUE self,
                                                       VALUE deadline) {
   grpc_rb_channel *wrapper = NULL;
   watch_state_stack stack;
-  void *out;
+  void *op_success = 0;
 
   TypedData_Get_Struct(self, grpc_rb_channel, &grpc_channel_data_type, wrapper);
 
-  if (wrapper->wrapped == NULL) {
+  if (wrapper->bg_wrapped == NULL) {
     rb_raise(rb_eRuntimeError, "closed!");
     return Qnil;
   }
@@ -323,16 +403,15 @@ static VALUE grpc_rb_channel_watch_connectivity_state(VALUE self,
     return Qnil;
   }
 
-  stack.wrapper = wrapper;
-  stack.deadline = grpc_rb_time_timeval(deadline, 0);
+  stack.channel = wrapper->bg_wrapped->channel;
+  stack.deadline = grpc_rb_time_timeval(deadline, 0),
   stack.last_state = NUM2LONG(last_state);
-  out =
-      rb_thread_call_without_gvl(watch_channel_state_without_gvl, &stack,
-                                 watch_channel_state_unblocking_func, wrapper);
-  if (out) {
-    return Qtrue;
-  }
-  return Qfalse;
+
+  op_success = rb_thread_call_without_gvl(
+      wait_for_watch_state_op_complete_without_gvl, &stack,
+      wait_for_watch_state_op_complete_unblocking_func, wrapper->bg_wrapped);
+
+  return op_success ? Qtrue : Qfalse;
 }
 
 /* Create a call given a grpc_channel, in order to call method. The request
@@ -344,7 +423,6 @@ static VALUE grpc_rb_channel_create_call(VALUE self, VALUE parent, VALUE mask,
   grpc_rb_channel *wrapper = NULL;
   grpc_call *call = NULL;
   grpc_call *parent_call = NULL;
-  grpc_channel *ch = NULL;
   grpc_completion_queue *cq = NULL;
   int flags = GRPC_PROPAGATE_DEFAULTS;
   grpc_slice method_slice;
@@ -366,8 +444,7 @@ static VALUE grpc_rb_channel_create_call(VALUE self, VALUE parent, VALUE mask,
 
   cq = grpc_completion_queue_create_for_pluck(NULL);
   TypedData_Get_Struct(self, grpc_rb_channel, &grpc_channel_data_type, wrapper);
-  ch = wrapper->wrapped;
-  if (ch == NULL) {
+  if (wrapper->bg_wrapped == NULL) {
     rb_raise(rb_eRuntimeError, "closed!");
     return Qnil;
   }
@@ -375,8 +452,8 @@ static VALUE grpc_rb_channel_create_call(VALUE self, VALUE parent, VALUE mask,
   method_slice =
       grpc_slice_from_copied_buffer(RSTRING_PTR(method), RSTRING_LEN(method));
 
-  call = grpc_channel_create_call(ch, parent_call, flags, cq, method_slice,
-                                  host_slice_ptr,
+  call = grpc_channel_create_call(wrapper->bg_wrapped->channel, parent_call,
+                                  flags, cq, method_slice, host_slice_ptr,
                                   grpc_rb_time_timeval(deadline,
                                                        /* absolute time */ 0),
                                   NULL);
@@ -401,15 +478,16 @@ static VALUE grpc_rb_channel_create_call(VALUE self, VALUE parent, VALUE mask,
 }
 
 /* Closes the channel, calling it's destroy method */
+/* Note this is an API-level call; a wrapped channel's finalizer doesn't call
+ * this */
 static VALUE grpc_rb_channel_destroy(VALUE self) {
   grpc_rb_channel *wrapper = NULL;
-  grpc_channel *ch = NULL;
 
   TypedData_Get_Struct(self, grpc_rb_channel, &grpc_channel_data_type, wrapper);
-  ch = wrapper->wrapped;
-  if (ch != NULL) {
-    grpc_rb_channel_safe_destroy(wrapper);
-    wrapper->wrapped = NULL;
+  if (wrapper->bg_wrapped != NULL) {
+    rb_thread_call_without_gvl(channel_safe_destroy_without_gil,
+                               wrapper->bg_wrapped, NULL, NULL);
+    wrapper->bg_wrapped = NULL;
   }
 
   return Qnil;
@@ -422,64 +500,110 @@ static VALUE grpc_rb_channel_get_target(VALUE self) {
   char *target = NULL;
 
   TypedData_Get_Struct(self, grpc_rb_channel, &grpc_channel_data_type, wrapper);
-  target = grpc_channel_get_target(wrapper->wrapped);
+  target = grpc_channel_get_target(wrapper->bg_wrapped->channel);
   res = rb_str_new2(target);
   gpr_free(target);
 
   return res;
 }
 
-// Either start polling channel connection state or signal that it's free to
-// destroy.
-// Not safe to call while a channel's connection state is polled.
-static void grpc_rb_channel_try_register_connection_polling(
-    grpc_rb_channel *wrapper) {
-  grpc_connectivity_state conn_state;
-  gpr_timespec sleep_time = gpr_time_add(
-      gpr_now(GPR_CLOCK_REALTIME), gpr_time_from_millis(20, GPR_TIMESPAN));
-
-  GPR_ASSERT(wrapper);
-  GPR_ASSERT(wrapper->wrapped);
-  gpr_mu_lock(&wrapper->channel_mu);
-  if (wrapper->request_safe_destroy) {
-    wrapper->safe_to_destroy = 1;
-    gpr_cv_broadcast(&wrapper->channel_cv);
-    gpr_mu_unlock(&wrapper->channel_mu);
-    return;
+/* Needs to be called under global_connection_polling_mu */
+static int bg_watched_channel_list_lookup(bg_watched_channel *target) {
+  bg_watched_channel *cur = bg_watched_channel_list_head;
+
+  while (cur != NULL) {
+    if (cur == target) {
+      return 1;
+    }
+    cur = cur->next;
   }
-  gpr_mu_lock(&global_connection_polling_mu);
 
-  GPR_ASSERT(channel_polling_thread_started || abort_channel_polling);
-  conn_state = grpc_channel_check_connectivity_state(wrapper->wrapped, 0);
-  if (conn_state != wrapper->current_connectivity_state) {
-    wrapper->current_connectivity_state = conn_state;
-    gpr_cv_broadcast(&wrapper->channel_cv);
-  }
-  // avoid posting work to the channel polling cq if it's been shutdown
-  if (!abort_channel_polling && conn_state != GRPC_CHANNEL_SHUTDOWN) {
-    grpc_channel_watch_connectivity_state(
-        wrapper->wrapped, conn_state, sleep_time, channel_polling_cq, wrapper);
-  } else {
-    wrapper->safe_to_destroy = 1;
-    gpr_cv_broadcast(&wrapper->channel_cv);
+  return 0;
+}
+
+/* Needs to be called under global_connection_polling_mu */
+static bg_watched_channel *bg_watched_channel_list_create_and_add(
+    grpc_channel *channel) {
+  bg_watched_channel *watched = gpr_zalloc(sizeof(bg_watched_channel));
+
+  watched->channel = channel;
+  watched->next = bg_watched_channel_list_head;
+  watched->refcount = 1;
+  bg_watched_channel_list_head = watched;
+  return watched;
+}
+
+/* Needs to be called under global_connection_polling_mu */
+static void bg_watched_channel_list_free_and_remove(
+    bg_watched_channel *target) {
+  bg_watched_channel *bg = NULL;
+
+  GPR_ASSERT(bg_watched_channel_list_lookup(target));
+  GPR_ASSERT(target->channel_destroyed && target->refcount == 0);
+  if (bg_watched_channel_list_head == target) {
+    bg_watched_channel_list_head = target->next;
+    gpr_free(target);
+    return;
+  }
+  bg = bg_watched_channel_list_head;
+  while (bg != NULL && bg->next != NULL) {
+    if (bg->next == target) {
+      bg->next = bg->next->next;
+      gpr_free(target);
+      return;
+    }
+    bg = bg->next;
   }
+  GPR_ASSERT(0);
+}
+
+/* Initialize a grpc_rb_channel's "protected grpc_channel" and try to push
+ * it onto the background thread for constant watches. */
+static void *channel_init_try_register_connection_polling_without_gil(
+    void *arg) {
+  channel_init_try_register_stack *stack =
+      (channel_init_try_register_stack *)arg;
+
+  gpr_mu_lock(&global_connection_polling_mu);
+  stack->wrapper->bg_wrapped =
+      bg_watched_channel_list_create_and_add(stack->channel);
+  grpc_rb_channel_try_register_connection_polling(stack->wrapper->bg_wrapped);
   gpr_mu_unlock(&global_connection_polling_mu);
-  gpr_mu_unlock(&wrapper->channel_mu);
+  return NULL;
 }
 
-// Note requires wrapper->wrapped, wrapper->channel_mu/cv initialized
-static void grpc_rb_channel_safe_destroy(grpc_rb_channel *wrapper) {
-  gpr_mu_lock(&wrapper->channel_mu);
-  wrapper->request_safe_destroy = 1;
+// Needs to be called under global_connection_poolling_mu
+static void grpc_rb_channel_try_register_connection_polling(
+    bg_watched_channel *bg) {
+  grpc_connectivity_state conn_state;
+  watch_state_op *op = NULL;
 
-  while (!wrapper->safe_to_destroy) {
-    gpr_cv_wait(&wrapper->channel_cv, &wrapper->channel_mu,
-                gpr_inf_future(GPR_CLOCK_REALTIME));
+  GPR_ASSERT(channel_polling_thread_started || abort_channel_polling);
+
+  if (bg->refcount == 0) {
+    GPR_ASSERT(bg->channel_destroyed);
+    bg_watched_channel_list_free_and_remove(bg);
+    return;
+  }
+  GPR_ASSERT(bg->refcount == 1);
+  if (bg->channel_destroyed || abort_channel_polling) {
+    return;
   }
-  GPR_ASSERT(wrapper->safe_to_destroy);
-  gpr_mu_unlock(&wrapper->channel_mu);
 
-  grpc_channel_destroy(wrapper->wrapped);
+  conn_state = grpc_channel_check_connectivity_state(bg->channel, 0);
+  if (conn_state == GRPC_CHANNEL_SHUTDOWN) {
+    return;
+  }
+  GPR_ASSERT(bg_watched_channel_list_lookup(bg));
+  // prevent bg from being free'd by GC while background thread is watching it
+  bg->refcount++;
+
+  op = gpr_zalloc(sizeof(watch_state_op));
+  op->op_type = CONTINUOUS_WATCH;
+  op->op.continuous_watch_callback_args.bg = bg;
+  grpc_channel_watch_connectivity_state(bg->channel, conn_state,
+                                        gpr_inf_future(GPR_CLOCK_REALTIME),
+                                        channel_polling_cq, op);
 }
 
 // Note this loop breaks out with a single call of
@@ -490,6 +614,8 @@ static void grpc_rb_channel_safe_destroy(grpc_rb_channel *wrapper) {
 // early and falls back to current behavior.
 static void *run_poll_channels_loop_no_gil(void *arg) {
   grpc_event event;
+  watch_state_op *op = NULL;
+  bg_watched_channel *bg = NULL;
   (void)arg;
   gpr_log(GPR_DEBUG, "GRPC_RUBY: run_poll_channels_loop_no_gil - begin");
 
@@ -505,10 +631,22 @@ static void *run_poll_channels_loop_no_gil(void *arg) {
     if (event.type == GRPC_QUEUE_SHUTDOWN) {
       break;
     }
+    gpr_mu_lock(&global_connection_polling_mu);
     if (event.type == GRPC_OP_COMPLETE) {
-      grpc_rb_channel_try_register_connection_polling(
-          (grpc_rb_channel *)event.tag);
+      op = (watch_state_op *)event.tag;
+      if (op->op_type == CONTINUOUS_WATCH) {
+        bg = (bg_watched_channel *)op->op.continuous_watch_callback_args.bg;
+        bg->refcount--;
+        grpc_rb_channel_try_register_connection_polling(bg);
+        gpr_free(op);
+      } else if (op->op_type == WATCH_STATE_API) {
+        grpc_rb_channel_watch_connection_state_op_complete(
+            (watch_state_op *)event.tag, event.success);
+      } else {
+        GPR_ASSERT(0);
+      }
     }
+    gpr_mu_unlock(&global_connection_polling_mu);
   }
   grpc_completion_queue_destroy(channel_polling_cq);
   gpr_log(GPR_DEBUG,
@@ -519,14 +657,36 @@ static void *run_poll_channels_loop_no_gil(void *arg) {
 
 // Notify the channel polling loop to cleanup and shutdown.
 static void run_poll_channels_loop_unblocking_func(void *arg) {
+  bg_watched_channel *bg = NULL;
   (void)arg;
+
   gpr_mu_lock(&global_connection_polling_mu);
   gpr_log(GPR_DEBUG,
-          "GRPC_RUBY: grpc_rb_event_unblocking_func - begin aborting "
+          "GRPC_RUBY: run_poll_channels_loop_unblocking_func - begin aborting "
           "connection polling");
+  // early out after first time through
+  if (abort_channel_polling) {
+    gpr_mu_unlock(&global_connection_polling_mu);
+    return;
+  }
   abort_channel_polling = 1;
+
+  // force pending watches to end by switching to shutdown state
+  bg = bg_watched_channel_list_head;
+  while (bg != NULL) {
+    if (!bg->channel_destroyed) {
+      grpc_channel_destroy(bg->channel);
+      bg->channel_destroyed = 1;
+    }
+    bg = bg->next;
+  }
+
   grpc_completion_queue_shutdown(channel_polling_cq);
+  gpr_cv_broadcast(&global_connection_polling_cv);
   gpr_mu_unlock(&global_connection_polling_mu);
+  gpr_log(GPR_DEBUG,
+          "GRPC_RUBY: run_poll_channels_loop_unblocking_func - end aborting "
+          "connection polling");
 }
 
 // Poll channel connectivity states in background thread without the GIL.
@@ -542,10 +702,11 @@ static VALUE run_poll_channels_loop(VALUE arg) {
 }
 
 static void *wait_until_channel_polling_thread_started_no_gil(void *arg) {
-  (void)arg;
+  int *stop_waiting = (int *)arg;
   gpr_log(GPR_DEBUG, "GRPC_RUBY: wait for channel polling thread to start");
   gpr_mu_lock(&global_connection_polling_mu);
-  while (!channel_polling_thread_started && !abort_channel_polling) {
+  while (!channel_polling_thread_started && !abort_channel_polling &&
+         !*stop_waiting) {
     gpr_cv_wait(&global_connection_polling_cv, &global_connection_polling_mu,
                 gpr_inf_future(GPR_CLOCK_REALTIME));
   }
@@ -556,15 +717,22 @@ static void *wait_until_channel_polling_thread_started_no_gil(void *arg) {
 
 static void wait_until_channel_polling_thread_started_unblocking_func(
     void *arg) {
-  (void)arg;
+  int *stop_waiting = (int *)arg;
   gpr_mu_lock(&global_connection_polling_mu);
   gpr_log(GPR_DEBUG,
-          "GRPC_RUBY: "
-          "wait_until_channel_polling_thread_started_unblocking_func - begin "
-          "aborting connection polling");
+          "GRPC_RUBY: interrupt wait for channel polling thread to start");
+  *stop_waiting = 1;
+  gpr_cv_broadcast(&global_connection_polling_cv);
+  gpr_mu_unlock(&global_connection_polling_mu);
+}
+
+static void *set_abort_channel_polling_without_gil(void *arg) {
+  (void)arg;
+  gpr_mu_lock(&global_connection_polling_mu);
   abort_channel_polling = 1;
   gpr_cv_broadcast(&global_connection_polling_cv);
   gpr_mu_unlock(&global_connection_polling_mu);
+  return NULL;
 }
 
 /* Temporary fix for
@@ -592,10 +760,8 @@ void grpc_rb_channel_polling_thread_start() {
 
   if (!RTEST(background_thread)) {
     gpr_log(GPR_DEBUG, "GRPC_RUBY: failed to spawn channel polling thread");
-    gpr_mu_lock(&global_connection_polling_mu);
-    abort_channel_polling = 1;
-    gpr_cv_broadcast(&global_connection_polling_cv);
-    gpr_mu_unlock(&global_connection_polling_mu);
+    rb_thread_call_without_gvl(set_abort_channel_polling_without_gil, NULL,
+                               NULL, NULL);
   }
 }
 
@@ -674,5 +840,5 @@ void Init_grpc_channel() {
 grpc_channel *grpc_rb_get_wrapped_channel(VALUE v) {
   grpc_rb_channel *wrapper = NULL;
   TypedData_Get_Struct(v, grpc_rb_channel, &grpc_channel_data_type, wrapper);
-  return wrapper->wrapped;
+  return wrapper->bg_wrapped->channel;
 }
diff --git a/src/ruby/ext/grpc/rb_event_thread.c b/src/ruby/ext/grpc/rb_event_thread.c
index 9a3b56ddfb..71138265c8 100644
--- a/src/ruby/ext/grpc/rb_event_thread.c
+++ b/src/ruby/ext/grpc/rb_event_thread.c
@@ -105,16 +105,16 @@ static void *grpc_rb_wait_for_event_no_gil(void *param) {
   grpc_rb_event *event = NULL;
   (void)param;
   gpr_mu_lock(&event_queue.mu);
-  while ((event = grpc_rb_event_queue_dequeue()) == NULL) {
-    gpr_cv_wait(&event_queue.cv, &event_queue.mu,
-                gpr_inf_future(GPR_CLOCK_REALTIME));
-    if (event_queue.abort) {
+  while (!event_queue.abort) {
+    if ((event = grpc_rb_event_queue_dequeue()) != NULL) {
       gpr_mu_unlock(&event_queue.mu);
-      return NULL;
+      return event;
     }
+    gpr_cv_wait(&event_queue.cv, &event_queue.mu,
+                gpr_inf_future(GPR_CLOCK_REALTIME));
   }
   gpr_mu_unlock(&event_queue.mu);
-  return event;
+  return NULL;
 }
 
 static void grpc_rb_event_unblocking_func(void *arg) {
diff --git a/src/ruby/ext/grpc/rb_grpc.c b/src/ruby/ext/grpc/rb_grpc.c
index 5be8861e0c..c319cd1391 100644
--- a/src/ruby/ext/grpc/rb_grpc.c
+++ b/src/ruby/ext/grpc/rb_grpc.c
@@ -292,11 +292,12 @@ static gpr_once g_once_init = GPR_ONCE_INIT;
 
 static void grpc_ruby_once_init_internal() {
   grpc_init();
-  grpc_rb_event_queue_thread_start();
-  grpc_rb_channel_polling_thread_start();
   atexit(grpc_rb_shutdown);
 }
 
+static VALUE bg_thread_init_rb_mu = Qundef;
+static int bg_thread_init_done = 0;
+
 void grpc_ruby_once_init() {
   /* ruby_vm_at_exit doesn't seem to be working. It would crash once every
    * blue moon, and some users are getting it repeatedly. See the discussions
@@ -309,6 +310,18 @@ void grpc_ruby_once_init() {
    * schedule our initialization and destruction only once.
    */
   gpr_once_init(&g_once_init, grpc_ruby_once_init_internal);
+
+  // Avoid calling calling into ruby library (when creating threads here)
+  // in gpr_once_init. In general, it appears to be unsafe to call
+  // into the ruby library while holding a non-ruby mutex, because a gil yield
+  // could end up trying to lock onto that same mutex and deadlocking.
+  rb_mutex_lock(bg_thread_init_rb_mu);
+  if (!bg_thread_init_done) {
+    grpc_rb_event_queue_thread_start();
+    grpc_rb_channel_polling_thread_start();
+    bg_thread_init_done = 1;
+  }
+  rb_mutex_unlock(bg_thread_init_rb_mu);
 }
 
 void Init_grpc_c() {
@@ -317,6 +330,9 @@ void Init_grpc_c() {
     return;
   }
 
+  bg_thread_init_rb_mu = rb_mutex_new();
+  rb_global_variable(&bg_thread_init_rb_mu);
+
   grpc_rb_mGRPC = rb_define_module("GRPC");
   grpc_rb_mGrpcCore = rb_define_module_under(grpc_rb_mGRPC, "Core");
   grpc_rb_sNewServerRpc = rb_struct_define(
diff --git a/src/ruby/ext/grpc/rb_grpc_imports.generated.c b/src/ruby/ext/grpc/rb_grpc_imports.generated.c
index 8f76420af6..f6a4ff6795 100644
--- a/src/ruby/ext/grpc/rb_grpc_imports.generated.c
+++ b/src/ruby/ext/grpc/rb_grpc_imports.generated.c
@@ -103,6 +103,7 @@ grpc_alarm_create_type grpc_alarm_create_import;
 grpc_alarm_cancel_type grpc_alarm_cancel_import;
 grpc_alarm_destroy_type grpc_alarm_destroy_import;
 grpc_channel_check_connectivity_state_type grpc_channel_check_connectivity_state_import;
+grpc_channel_num_external_connectivity_watchers_type grpc_channel_num_external_connectivity_watchers_import;
 grpc_channel_watch_connectivity_state_type grpc_channel_watch_connectivity_state_import;
 grpc_channel_create_call_type grpc_channel_create_call_import;
 grpc_channel_ping_type grpc_channel_ping_import;
@@ -405,6 +406,7 @@ void grpc_rb_load_imports(HMODULE library) {
   grpc_alarm_cancel_import = (grpc_alarm_cancel_type) GetProcAddress(library, "grpc_alarm_cancel");
   grpc_alarm_destroy_import = (grpc_alarm_destroy_type) GetProcAddress(library, "grpc_alarm_destroy");
   grpc_channel_check_connectivity_state_import = (grpc_channel_check_connectivity_state_type) GetProcAddress(library, "grpc_channel_check_connectivity_state");
+  grpc_channel_num_external_connectivity_watchers_import = (grpc_channel_num_external_connectivity_watchers_type) GetProcAddress(library, "grpc_channel_num_external_connectivity_watchers");
   grpc_channel_watch_connectivity_state_import = (grpc_channel_watch_connectivity_state_type) GetProcAddress(library, "grpc_channel_watch_connectivity_state");
   grpc_channel_create_call_import = (grpc_channel_create_call_type) GetProcAddress(library, "grpc_channel_create_call");
   grpc_channel_ping_import = (grpc_channel_ping_type) GetProcAddress(library, "grpc_channel_ping");
diff --git a/src/ruby/ext/grpc/rb_grpc_imports.generated.h b/src/ruby/ext/grpc/rb_grpc_imports.generated.h
index 58467f97e8..0d64290b55 100644
--- a/src/ruby/ext/grpc/rb_grpc_imports.generated.h
+++ b/src/ruby/ext/grpc/rb_grpc_imports.generated.h
@@ -260,6 +260,9 @@ extern grpc_alarm_destroy_type grpc_alarm_destroy_import;
 typedef grpc_connectivity_state(*grpc_channel_check_connectivity_state_type)(grpc_channel *channel, int try_to_connect);
 extern grpc_channel_check_connectivity_state_type grpc_channel_check_connectivity_state_import;
 #define grpc_channel_check_connectivity_state grpc_channel_check_connectivity_state_import
+typedef int(*grpc_channel_num_external_connectivity_watchers_type)(grpc_channel *channel);
+extern grpc_channel_num_external_connectivity_watchers_type grpc_channel_num_external_connectivity_watchers_import;
+#define grpc_channel_num_external_connectivity_watchers grpc_channel_num_external_connectivity_watchers_import
 typedef void(*grpc_channel_watch_connectivity_state_type)(grpc_channel *channel, grpc_connectivity_state last_observed_state, gpr_timespec deadline, grpc_completion_queue *cq, void *tag);
 extern grpc_channel_watch_connectivity_state_type grpc_channel_watch_connectivity_state_import;
 #define grpc_channel_watch_connectivity_state grpc_channel_watch_connectivity_state_import
diff --git a/src/ruby/spec/channel_connection_spec.rb b/src/ruby/spec/channel_connection_spec.rb
index 940d68b9b0..c8a7856a09 100644
--- a/src/ruby/spec/channel_connection_spec.rb
+++ b/src/ruby/spec/channel_connection_spec.rb
@@ -28,6 +28,10 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 require 'grpc'
+require 'timeout'
+
+include Timeout
+include GRPC::Core
 
 # A test message
 class EchoMsg
@@ -62,7 +66,7 @@ end
 EchoStub = EchoService.rpc_stub_class
 
 def start_server(port = 0)
-  @srv = GRPC::RpcServer.new
+  @srv = GRPC::RpcServer.new(pool_size: 1)
   server_port = @srv.add_http2_port("localhost:#{port}", :this_port_is_insecure)
   @srv.handle(EchoService)
   @server_thd = Thread.new { @srv.run }
@@ -138,4 +142,32 @@ describe 'channel connection behavior' do
 
     stop_server
   end
+
+  it 'concurrent watches on the same channel' do
+    timeout(180) do
+      port = start_server
+      ch = GRPC::Core::Channel.new("localhost:#{port}", {},
+                                   :this_channel_is_insecure)
+      stop_server
+
+      thds = []
+      50.times do
+        thds << Thread.new do
+          while ch.connectivity_state(true) != ConnectivityStates::READY
+            ch.watch_connectivity_state(
+              ConnectivityStates::READY, Time.now + 60)
+            break
+          end
+        end
+      end
+
+      sleep 0.01
+
+      start_server(port)
+
+      thds.each(&:join)
+
+      stop_server
+    end
+  end
 end
diff --git a/templates/src/csharp/build_packages_dotnetcli.bat.template b/templates/src/csharp/build_packages_dotnetcli.bat.template
index 8624c34782..3db1e0ac3d 100755
--- a/templates/src/csharp/build_packages_dotnetcli.bat.template
+++ b/templates/src/csharp/build_packages_dotnetcli.bat.template
@@ -53,11 +53,11 @@
   @rem To be able to build, we also need to put grpc_csharp_ext to its normal location
   xcopy /Y /I nativelibs\csharp_ext_windows_x64\grpc_csharp_ext.dll ..\..\cmake\build\x64\Release${"\\"}
   
-  %%DOTNET% pack --configuration Release --include-symbols --include-source Grpc.Core --output ..\..\..\artifacts || goto :error
-  %%DOTNET% pack --configuration Release --include-symbols --include-source Grpc.Core.Testing --output ..\..\..\artifacts || goto :error
-  %%DOTNET% pack --configuration Release --include-symbols --include-source Grpc.Auth --output ..\..\..\artifacts || goto :error
-  %%DOTNET% pack --configuration Release --include-symbols --include-source Grpc.HealthCheck --output ..\..\..\artifacts || goto :error
-  %%DOTNET% pack --configuration Release --include-symbols --include-source Grpc.Reflection --output ..\..\..\artifacts || goto :error
+  %%DOTNET% pack --configuration Release Grpc.Core --output ..\..\..\artifacts || goto :error
+  %%DOTNET% pack --configuration Release Grpc.Core.Testing --output ..\..\..\artifacts || goto :error
+  %%DOTNET% pack --configuration Release Grpc.Auth --output ..\..\..\artifacts || goto :error
+  %%DOTNET% pack --configuration Release Grpc.HealthCheck --output ..\..\..\artifacts || goto :error
+  %%DOTNET% pack --configuration Release Grpc.Reflection --output ..\..\..\artifacts || goto :error
   
   %%NUGET% pack Grpc.nuspec -Version %VERSION% -OutputDirectory ..\..\artifacts || goto :error
   %%NUGET% pack Grpc.Tools.nuspec -Version %VERSION% -OutputDirectory ..\..\artifacts
diff --git a/templates/src/csharp/build_packages_dotnetcli.sh.template b/templates/src/csharp/build_packages_dotnetcli.sh.template
index bff497c85a..65afec55c4 100755
--- a/templates/src/csharp/build_packages_dotnetcli.sh.template
+++ b/templates/src/csharp/build_packages_dotnetcli.sh.template
@@ -50,11 +50,11 @@
   mkdir -p ../../libs/opt
   cp nativelibs/csharp_ext_linux_x64/libgrpc_csharp_ext.so ../../libs/opt
   
-  dotnet pack --configuration Release --include-symbols --include-source Grpc.Core --output ../../../artifacts
-  dotnet pack --configuration Release --include-symbols --include-source Grpc.Core.Testing --output ../../../artifacts
-  dotnet pack --configuration Release --include-symbols --include-source Grpc.Auth --output ../../../artifacts
-  dotnet pack --configuration Release --include-symbols --include-source Grpc.HealthCheck --output ../../../artifacts
-  dotnet pack --configuration Release --include-symbols --include-source Grpc.Reflection --output ../../../artifacts
+  dotnet pack --configuration Release Grpc.Core --output ../../../artifacts
+  dotnet pack --configuration Release Grpc.Core.Testing --output ../../../artifacts
+  dotnet pack --configuration Release Grpc.Auth --output ../../../artifacts
+  dotnet pack --configuration Release Grpc.HealthCheck --output ../../../artifacts
+  dotnet pack --configuration Release Grpc.Reflection --output ../../../artifacts
   
   nuget pack Grpc.nuspec -Version "${settings.csharp_version}" -OutputDirectory ../../artifacts
   nuget pack Grpc.Tools.nuspec -Version "${settings.csharp_version}" -OutputDirectory ../../artifacts
diff --git a/test/core/surface/concurrent_connectivity_test.c b/test/core/surface/concurrent_connectivity_test.c
index 87ad095170..7614696cae 100644
--- a/test/core/surface/concurrent_connectivity_test.c
+++ b/test/core/surface/concurrent_connectivity_test.c
@@ -61,6 +61,14 @@
 #define DELAY_MILLIS 10
 #define POLL_MILLIS 3000
 
+#define NUM_OUTER_LOOPS_SHORT_TIMEOUTS 10
+#define NUM_INNER_LOOPS_SHORT_TIMEOUTS 100
+#define DELAY_MILLIS_SHORT_TIMEOUTS 1
+// in a successful test run, POLL_MILLIS should never be reached beause all runs
+// should
+// end after the shorter delay_millis
+#define POLL_MILLIS_SHORT_TIMEOUTS 30000
+
 static void *tag(int n) { return (void *)(uintptr_t)n; }
 static int detag(void *p) { return (int)(uintptr_t)p; }
 
@@ -79,6 +87,8 @@ void create_loop_destroy(void *addr) {
           grpc_timeout_milliseconds_to_deadline(POLL_MILLIS);
       GPR_ASSERT(grpc_completion_queue_next(cq, poll_time, NULL).type ==
                  GRPC_OP_COMPLETE);
+      /* check that the watcher from "watch state" was free'd */
+      GPR_ASSERT(grpc_channel_num_external_connectivity_watchers(chan) == 0);
     }
     grpc_channel_destroy(chan);
     grpc_completion_queue_destroy(cq);
@@ -168,11 +178,10 @@ static void done_pollset_shutdown(grpc_exec_ctx *exec_ctx, void *pollset,
   gpr_free(pollset);
 }
 
-int main(int argc, char **argv) {
+int run_concurrent_connectivity_test() {
   struct server_thread_args args;
   memset(&args, 0, sizeof(args));
 
-  grpc_test_init(argc, argv);
   grpc_init();
 
   gpr_thd_id threads[NUM_THREADS];
@@ -242,3 +251,59 @@ int main(int argc, char **argv) {
   grpc_shutdown();
   return 0;
 }
+
+void watches_with_short_timeouts(void *addr) {
+  for (int i = 0; i < NUM_OUTER_LOOPS_SHORT_TIMEOUTS; ++i) {
+    grpc_completion_queue *cq = grpc_completion_queue_create_for_next(NULL);
+    grpc_channel *chan = grpc_insecure_channel_create((char *)addr, NULL, NULL);
+
+    for (int j = 0; j < NUM_INNER_LOOPS_SHORT_TIMEOUTS; ++j) {
+      gpr_timespec later_time =
+          grpc_timeout_milliseconds_to_deadline(DELAY_MILLIS_SHORT_TIMEOUTS);
+      grpc_connectivity_state state =
+          grpc_channel_check_connectivity_state(chan, 0);
+      GPR_ASSERT(state == GRPC_CHANNEL_IDLE);
+      grpc_channel_watch_connectivity_state(chan, state, later_time, cq, NULL);
+      gpr_timespec poll_time =
+          grpc_timeout_milliseconds_to_deadline(POLL_MILLIS_SHORT_TIMEOUTS);
+      grpc_event ev = grpc_completion_queue_next(cq, poll_time, NULL);
+      GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
+      GPR_ASSERT(ev.success == false);
+      /* check that the watcher from "watch state" was free'd */
+      GPR_ASSERT(grpc_channel_num_external_connectivity_watchers(chan) == 0);
+    }
+    grpc_channel_destroy(chan);
+    grpc_completion_queue_destroy(cq);
+  }
+}
+
+// This test tries to catch deadlock situations.
+// With short timeouts on "watches" and long timeouts on cq next calls,
+// so that a QUEUE_TIMEOUT likely means that something is stuck.
+int run_concurrent_watches_with_short_timeouts_test() {
+  grpc_init();
+
+  gpr_thd_id threads[NUM_THREADS];
+
+  char *localhost = gpr_strdup("localhost:54321");
+  gpr_thd_options options = gpr_thd_options_default();
+  gpr_thd_options_set_joinable(&options);
+
+  for (size_t i = 0; i < NUM_THREADS; ++i) {
+    gpr_thd_new(&threads[i], watches_with_short_timeouts, localhost, &options);
+  }
+  for (size_t i = 0; i < NUM_THREADS; ++i) {
+    gpr_thd_join(threads[i]);
+  }
+  gpr_free(localhost);
+
+  grpc_shutdown();
+  return 0;
+}
+
+int main(int argc, char **argv) {
+  grpc_test_init(argc, argv);
+
+  run_concurrent_connectivity_test();
+  run_concurrent_watches_with_short_timeouts_test();
+}
diff --git a/test/core/surface/num_external_connectivity_watchers_test.c b/test/core/surface/num_external_connectivity_watchers_test.c
new file mode 100644
index 0000000000..93944c9ad5
--- /dev/null
+++ b/test/core/surface/num_external_connectivity_watchers_test.c
@@ -0,0 +1,214 @@
+/*
+ *
+ * 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 <grpc/grpc.h>
+#include <grpc/grpc_security.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/host_port.h>
+#include <grpc/support/log.h>
+#include <grpc/support/thd.h>
+
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
+#include "test/core/end2end/data/ssl_test_data.h"
+#include "test/core/util/port.h"
+#include "test/core/util/test_config.h"
+
+typedef struct test_fixture {
+  const char *name;
+  grpc_channel *(*create_channel)(const char *addr);
+} test_fixture;
+
+static size_t next_tag = 1;
+
+static void channel_idle_start_watch(grpc_channel *channel,
+                                     grpc_completion_queue *cq) {
+  gpr_timespec connect_deadline = grpc_timeout_milliseconds_to_deadline(1);
+  GPR_ASSERT(grpc_channel_check_connectivity_state(channel, 0) ==
+             GRPC_CHANNEL_IDLE);
+
+  grpc_channel_watch_connectivity_state(
+      channel, GRPC_CHANNEL_IDLE, connect_deadline, cq, (void *)(next_tag++));
+  gpr_log(GPR_DEBUG, "number of active connect watchers: %d",
+          grpc_channel_num_external_connectivity_watchers(channel));
+}
+
+static void channel_idle_poll_for_timeout(grpc_channel *channel,
+                                          grpc_completion_queue *cq) {
+  grpc_event ev =
+      grpc_completion_queue_next(cq, gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+
+  /* expect watch_connectivity_state to end with a timeout */
+  GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
+  GPR_ASSERT(ev.success == false);
+  GPR_ASSERT(grpc_channel_check_connectivity_state(channel, 0) ==
+             GRPC_CHANNEL_IDLE);
+}
+
+/* Test and use the "num_external_watchers" call to make sure
+ * that "connectivity watcher" structs are free'd just after, if
+ * their corresponding timeouts occur. */
+static void run_timeouts_test(const test_fixture *fixture) {
+  gpr_log(GPR_INFO, "TEST: %s", fixture->name);
+
+  char *addr;
+
+  grpc_init();
+
+  gpr_join_host_port(&addr, "localhost", grpc_pick_unused_port_or_die());
+
+  grpc_channel *channel = fixture->create_channel(addr);
+  grpc_completion_queue *cq = grpc_completion_queue_create_for_next(NULL);
+
+  /* start 1 watcher and then let it time out */
+  channel_idle_start_watch(channel, cq);
+  channel_idle_poll_for_timeout(channel, cq);
+  GPR_ASSERT(grpc_channel_num_external_connectivity_watchers(channel) == 0);
+
+  /* start 3 watchers and then let them all time out */
+  for (size_t i = 1; i <= 3; i++) {
+    channel_idle_start_watch(channel, cq);
+  }
+  for (size_t i = 1; i <= 3; i++) {
+    channel_idle_poll_for_timeout(channel, cq);
+  }
+  GPR_ASSERT(grpc_channel_num_external_connectivity_watchers(channel) == 0);
+
+  /* start 3 watchers, see one time out, start another 3, and then see them all
+   * time out */
+  for (size_t i = 1; i <= 3; i++) {
+    channel_idle_start_watch(channel, cq);
+  }
+  channel_idle_poll_for_timeout(channel, cq);
+  for (size_t i = 3; i <= 5; i++) {
+    channel_idle_start_watch(channel, cq);
+  }
+  for (size_t i = 1; i <= 5; i++) {
+    channel_idle_poll_for_timeout(channel, cq);
+  }
+  GPR_ASSERT(grpc_channel_num_external_connectivity_watchers(channel) == 0);
+
+  grpc_channel_destroy(channel);
+  grpc_completion_queue_shutdown(cq);
+  GPR_ASSERT(
+      grpc_completion_queue_next(cq, gpr_inf_future(GPR_CLOCK_REALTIME), NULL)
+          .type == GRPC_QUEUE_SHUTDOWN);
+  grpc_completion_queue_destroy(cq);
+
+  grpc_shutdown();
+  gpr_free(addr);
+}
+
+/* An edge scenario; sets channel state to explicitly, and outside
+ * of a polling call. */
+static void run_channel_shutdown_before_timeout_test(
+    const test_fixture *fixture) {
+  gpr_log(GPR_INFO, "TEST: %s", fixture->name);
+
+  char *addr;
+
+  grpc_init();
+
+  gpr_join_host_port(&addr, "localhost", grpc_pick_unused_port_or_die());
+
+  grpc_channel *channel = fixture->create_channel(addr);
+  grpc_completion_queue *cq = grpc_completion_queue_create_for_next(NULL);
+
+  /* start 1 watcher and then shut down the channel before the timer goes off */
+  GPR_ASSERT(grpc_channel_num_external_connectivity_watchers(channel) == 0);
+
+  /* expecting a 30 second timeout to go off much later than the shutdown. */
+  gpr_timespec connect_deadline = grpc_timeout_seconds_to_deadline(30);
+  GPR_ASSERT(grpc_channel_check_connectivity_state(channel, 0) ==
+             GRPC_CHANNEL_IDLE);
+
+  grpc_channel_watch_connectivity_state(channel, GRPC_CHANNEL_IDLE,
+                                        connect_deadline, cq, (void *)1);
+  grpc_channel_destroy(channel);
+
+  grpc_event ev =
+      grpc_completion_queue_next(cq, gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+  GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
+  /* expect success with a state transition to CHANNEL_SHUTDOWN */
+  GPR_ASSERT(ev.success == true);
+
+  grpc_completion_queue_shutdown(cq);
+  GPR_ASSERT(
+      grpc_completion_queue_next(cq, gpr_inf_future(GPR_CLOCK_REALTIME), NULL)
+          .type == GRPC_QUEUE_SHUTDOWN);
+  grpc_completion_queue_destroy(cq);
+
+  grpc_shutdown();
+  gpr_free(addr);
+}
+
+static grpc_channel *insecure_test_create_channel(const char *addr) {
+  return grpc_insecure_channel_create(addr, NULL, NULL);
+}
+
+static const test_fixture insecure_test = {
+    "insecure", insecure_test_create_channel,
+};
+
+static grpc_channel *secure_test_create_channel(const char *addr) {
+  grpc_channel_credentials *ssl_creds =
+      grpc_ssl_credentials_create(test_root_cert, NULL, NULL);
+  grpc_arg ssl_name_override = {GRPC_ARG_STRING,
+                                GRPC_SSL_TARGET_NAME_OVERRIDE_ARG,
+                                {"foo.test.google.fr"}};
+  grpc_channel_args *new_client_args =
+      grpc_channel_args_copy_and_add(NULL, &ssl_name_override, 1);
+  grpc_channel *channel =
+      grpc_secure_channel_create(ssl_creds, addr, new_client_args, NULL);
+  {
+    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+    grpc_channel_args_destroy(&exec_ctx, new_client_args);
+    grpc_exec_ctx_finish(&exec_ctx);
+  }
+  grpc_channel_credentials_release(ssl_creds);
+  return channel;
+}
+
+static const test_fixture secure_test = {
+    "secure", secure_test_create_channel,
+};
+
+int main(int argc, char **argv) {
+  grpc_test_init(argc, argv);
+
+  run_timeouts_test(&insecure_test);
+  run_timeouts_test(&secure_test);
+
+  run_channel_shutdown_before_timeout_test(&insecure_test);
+  run_channel_shutdown_before_timeout_test(&secure_test);
+}
diff --git a/test/core/surface/sequential_connectivity_test.c b/test/core/surface/sequential_connectivity_test.c
index fbecdd7e38..a0f18e9bbf 100644
--- a/test/core/surface/sequential_connectivity_test.c
+++ b/test/core/surface/sequential_connectivity_test.c
@@ -100,6 +100,9 @@ static void run_test(const test_fixture *fixture) {
                                             connect_deadline, cq, NULL);
       grpc_event ev = grpc_completion_queue_next(
           cq, gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+      /* check that the watcher from "watch state" was free'd */
+      GPR_ASSERT(grpc_channel_num_external_connectivity_watchers(channels[i]) ==
+                 0);
       GPR_ASSERT(ev.type == GRPC_OP_COMPLETE);
       GPR_ASSERT(ev.tag == NULL);
       GPR_ASSERT(ev.success == true);
diff --git a/tools/run_tests/generated/sources_and_headers.json b/tools/run_tests/generated/sources_and_headers.json
index 97e079d8a8..6c4462e9f2 100644
--- a/tools/run_tests/generated/sources_and_headers.json
+++ b/tools/run_tests/generated/sources_and_headers.json
@@ -1765,6 +1765,23 @@
     "headers": [], 
     "is_filegroup": false, 
     "language": "c", 
+    "name": "num_external_connectivity_watchers_test", 
+    "src": [
+      "test/core/surface/num_external_connectivity_watchers_test.c"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "is_filegroup": false, 
+    "language": "c", 
     "name": "parse_address_test", 
     "src": [
       "test/core/client_channel/parse_address_test.c"
diff --git a/tools/run_tests/generated/tests.json b/tools/run_tests/generated/tests.json
index 82db441a1a..1242025fc2 100644
--- a/tools/run_tests/generated/tests.json
+++ b/tools/run_tests/generated/tests.json
@@ -1839,6 +1839,30 @@
     ], 
     "cpu_cost": 1.0, 
     "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "gtest": false, 
+    "language": "c", 
+    "name": "num_external_connectivity_watchers_test", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix", 
+      "windows"
+    ]
+  }, 
+  {
+    "args": [], 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
+      "posix", 
+      "windows"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
     "exclude_iomgrs": [], 
     "flaky": false, 
     "gtest": false, 
diff --git a/tools/run_tests/helper_scripts/run_ruby_end2end_tests.sh b/tools/run_tests/helper_scripts/run_ruby_end2end_tests.sh
index 6688025260..ab882d62bc 100755
--- a/tools/run_tests/helper_scripts/run_ruby_end2end_tests.sh
+++ b/tools/run_tests/helper_scripts/run_ruby_end2end_tests.sh
@@ -41,4 +41,5 @@ ruby src/ruby/end2end/sig_int_during_channel_watch_driver.rb || EXIT_CODE=1
 ruby src/ruby/end2end/killed_client_thread_driver.rb || EXIT_CODE=1
 ruby src/ruby/end2end/forking_client_driver.rb || EXIT_CODE=1
 ruby src/ruby/end2end/grpc_class_init_driver.rb || EXIT_CODE=1
+ruby src/ruby/end2end/multiple_killed_watching_threads_driver.rb || EXIT_CODE=1
 exit $EXIT_CODE
diff --git a/vsprojects/buildtests_c.sln b/vsprojects/buildtests_c.sln
index 284dd68c16..b7696a9965 100644
--- a/vsprojects/buildtests_c.sln
+++ b/vsprojects/buildtests_c.sln
@@ -1350,6 +1350,17 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "no_server_test", "vcxproj\t
 		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792} = {B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}
 	EndProjectSection
 EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "num_external_connectivity_watchers_test", "vcxproj\test\num_external_connectivity_watchers_test\num_external_connectivity_watchers_test.vcxproj", "{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}"
+	ProjectSection(myProperties) = preProject
+        	lib = "False"
+	EndProjectSection
+	ProjectSection(ProjectDependencies) = postProject
+		{17BCAFC0-5FDC-4C94-AEB9-95F3E220614B} = {17BCAFC0-5FDC-4C94-AEB9-95F3E220614B}
+		{29D16885-7228-4C31-81ED-5F9187C7F2A9} = {29D16885-7228-4C31-81ED-5F9187C7F2A9}
+		{EAB0A629-17A9-44DB-B5FF-E91A721FE037} = {EAB0A629-17A9-44DB-B5FF-E91A721FE037}
+		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792} = {B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}
+	EndProjectSection
+EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "parse_address_test", "vcxproj\test\parse_address_test\parse_address_test.vcxproj", "{EDEA8257-AEA8-1B0A-F95B-8D6CD7286463}"
 	ProjectSection(myProperties) = preProject
         	lib = "False"
@@ -3750,6 +3761,22 @@ Global
 		{A66AC548-E2B9-74CD-293C-43526EE51DCE}.Release-DLL|Win32.Build.0 = Release|Win32
 		{A66AC548-E2B9-74CD-293C-43526EE51DCE}.Release-DLL|x64.ActiveCfg = Release|x64
 		{A66AC548-E2B9-74CD-293C-43526EE51DCE}.Release-DLL|x64.Build.0 = Release|x64
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Debug|Win32.ActiveCfg = Debug|Win32
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Debug|x64.ActiveCfg = Debug|x64
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Release|Win32.ActiveCfg = Release|Win32
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Release|x64.ActiveCfg = Release|x64
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Debug|Win32.Build.0 = Debug|Win32
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Debug|x64.Build.0 = Debug|x64
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Release|Win32.Build.0 = Release|Win32
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Release|x64.Build.0 = Release|x64
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Debug-DLL|Win32.ActiveCfg = Debug|Win32
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Debug-DLL|Win32.Build.0 = Debug|Win32
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Debug-DLL|x64.ActiveCfg = Debug|x64
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Debug-DLL|x64.Build.0 = Debug|x64
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Release-DLL|Win32.ActiveCfg = Release|Win32
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Release-DLL|Win32.Build.0 = Release|Win32
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Release-DLL|x64.ActiveCfg = Release|x64
+		{4E856E4A-7497-1B1A-1AED-D4C01E5D873A}.Release-DLL|x64.Build.0 = Release|x64
 		{EDEA8257-AEA8-1B0A-F95B-8D6CD7286463}.Debug|Win32.ActiveCfg = Debug|Win32
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diff --git a/vsprojects/vcxproj/test/num_external_connectivity_watchers_test/num_external_connectivity_watchers_test.vcxproj b/vsprojects/vcxproj/test/num_external_connectivity_watchers_test/num_external_connectivity_watchers_test.vcxproj
new file mode 100644
index 0000000000..2b373e8a16
--- /dev/null
+++ b/vsprojects/vcxproj/test/num_external_connectivity_watchers_test/num_external_connectivity_watchers_test.vcxproj
@@ -0,0 +1,199 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="12.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.1.0.204.1\build\native\grpc.dependencies.openssl.props" Condition="Exists('$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.1.0.204.1\build\native\1.0.204.1.props')" />
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+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
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+    <IgnoreWarnIntDirInTempDetected>true</IgnoreWarnIntDirInTempDetected>
+    <IntDir>$(SolutionDir)IntDir\$(MSBuildProjectName)\</IntDir>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(VisualStudioVersion)' == '10.0'" Label="Configuration">
+    <PlatformToolset>v100</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(VisualStudioVersion)' == '11.0'" Label="Configuration">
+    <PlatformToolset>v110</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(VisualStudioVersion)' == '12.0'" Label="Configuration">
+    <PlatformToolset>v120</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(VisualStudioVersion)' == '14.0'" Label="Configuration">
+    <PlatformToolset>v140</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)'=='Debug'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)'=='Release'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+    <Import Project="$(SolutionDir)\..\vsprojects\global.props" />
+    <Import Project="$(SolutionDir)\..\vsprojects\openssl.props" />
+    <Import Project="$(SolutionDir)\..\vsprojects\winsock.props" />
+    <Import Project="$(SolutionDir)\..\vsprojects\zlib.props" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup Condition="'$(Configuration)'=='Debug'">
+    <TargetName>num_external_connectivity_watchers_test</TargetName>
+    <Linkage-grpc_dependencies_zlib>static</Linkage-grpc_dependencies_zlib>
+    <Configuration-grpc_dependencies_zlib>Debug</Configuration-grpc_dependencies_zlib>
+    <Linkage-grpc_dependencies_openssl>static</Linkage-grpc_dependencies_openssl>
+    <Configuration-grpc_dependencies_openssl>Debug</Configuration-grpc_dependencies_openssl>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)'=='Release'">
+    <TargetName>num_external_connectivity_watchers_test</TargetName>
+    <Linkage-grpc_dependencies_zlib>static</Linkage-grpc_dependencies_zlib>
+    <Configuration-grpc_dependencies_zlib>Release</Configuration-grpc_dependencies_zlib>
+    <Linkage-grpc_dependencies_openssl>static</Linkage-grpc_dependencies_openssl>
+    <Configuration-grpc_dependencies_openssl>Release</Configuration-grpc_dependencies_openssl>
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+    <ClCompile>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <WarningLevel>Level3</WarningLevel>
+      <Optimization>Disabled</Optimization>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_LIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <SDLCheck>true</SDLCheck>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
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+      <DebugInformationFormat Condition="$(Jenkins)">None</DebugInformationFormat>
+      <MinimalRebuild Condition="$(Jenkins)">false</MinimalRebuild>
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+    <Link>
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+    <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
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+      <SDLCheck>true</SDLCheck>
+      <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
+      <TreatWarningAsError>true</TreatWarningAsError>
+      <DebugInformationFormat Condition="$(Jenkins)">None</DebugInformationFormat>
+      <MinimalRebuild Condition="$(Jenkins)">false</MinimalRebuild>
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+    <Link>
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+      <GenerateDebugInformation Condition="!$(Jenkins)">true</GenerateDebugInformation>
+      <GenerateDebugInformation Condition="$(Jenkins)">false</GenerateDebugInformation>
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+
+    <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <ClCompile>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <WarningLevel>Level3</WarningLevel>
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+      <FunctionLevelLinking>true</FunctionLevelLinking>
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+      <DebugInformationFormat Condition="$(Jenkins)">None</DebugInformationFormat>
+      <MinimalRebuild Condition="$(Jenkins)">false</MinimalRebuild>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation Condition="!$(Jenkins)">true</GenerateDebugInformation>
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+      <OptimizeReferences>true</OptimizeReferences>
+    </Link>
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+
+    <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <ClCompile>
+      <PrecompiledHeader>NotUsing</PrecompiledHeader>
+      <WarningLevel>Level3</WarningLevel>
+      <Optimization>MaxSpeed</Optimization>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_LIB;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <FunctionLevelLinking>true</FunctionLevelLinking>
+      <IntrinsicFunctions>true</IntrinsicFunctions>
+      <SDLCheck>true</SDLCheck>
+      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
+      <TreatWarningAsError>true</TreatWarningAsError>
+      <DebugInformationFormat Condition="$(Jenkins)">None</DebugInformationFormat>
+      <MinimalRebuild Condition="$(Jenkins)">false</MinimalRebuild>
+    </ClCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+      <GenerateDebugInformation Condition="!$(Jenkins)">true</GenerateDebugInformation>
+      <GenerateDebugInformation Condition="$(Jenkins)">false</GenerateDebugInformation>
+      <EnableCOMDATFolding>true</EnableCOMDATFolding>
+      <OptimizeReferences>true</OptimizeReferences>
+    </Link>
+  </ItemDefinitionGroup>
+
+  <ItemGroup>
+    <ClCompile Include="$(SolutionDir)\..\test\core\surface\num_external_connectivity_watchers_test.c">
+    </ClCompile>
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="$(SolutionDir)\..\vsprojects\vcxproj\.\grpc_test_util\grpc_test_util.vcxproj">
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+  <ImportGroup Label="ExtensionTargets">
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+  </ImportGroup>
+  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
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+      <ErrorText>This project references NuGet package(s) that are missing on this computer. Enable NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
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diff --git a/vsprojects/vcxproj/test/num_external_connectivity_watchers_test/num_external_connectivity_watchers_test.vcxproj.filters b/vsprojects/vcxproj/test/num_external_connectivity_watchers_test/num_external_connectivity_watchers_test.vcxproj.filters
new file mode 100644
index 0000000000..92a4198e30
--- /dev/null
+++ b/vsprojects/vcxproj/test/num_external_connectivity_watchers_test/num_external_connectivity_watchers_test.vcxproj.filters
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
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