Merge github.com:grpc/grpc into bye-bye-completion-queue-pie

15 files changed, 460 insertions, 118 deletions

diff --git a/Makefile b/Makefile
index b28c93bf52..00ef782759 100644
--- a/Makefile
+++ b/Makefile
@@ -695,6 +695,7 @@ status_test: $(BINDIR)/$(CONFIG)/status_test
 sync_streaming_ping_pong_test: $(BINDIR)/$(CONFIG)/sync_streaming_ping_pong_test
 sync_unary_ping_pong_test: $(BINDIR)/$(CONFIG)/sync_unary_ping_pong_test
 thread_pool_test: $(BINDIR)/$(CONFIG)/thread_pool_test
+thread_stress_test: $(BINDIR)/$(CONFIG)/thread_stress_test
 chttp2_fake_security_bad_hostname_test: $(BINDIR)/$(CONFIG)/chttp2_fake_security_bad_hostname_test
 chttp2_fake_security_cancel_after_accept_test: $(BINDIR)/$(CONFIG)/chttp2_fake_security_cancel_after_accept_test
 chttp2_fake_security_cancel_after_accept_and_writes_closed_test: $(BINDIR)/$(CONFIG)/chttp2_fake_security_cancel_after_accept_and_writes_closed_test
@@ -1082,7 +1083,7 @@ buildtests: buildtests_c buildtests_cxx
 
 buildtests_c: privatelibs_c $(BINDIR)/$(CONFIG)/alarm_heap_test $(BINDIR)/$(CONFIG)/alarm_list_test $(BINDIR)/$(CONFIG)/alarm_test $(BINDIR)/$(CONFIG)/alpn_test $(BINDIR)/$(CONFIG)/bin_encoder_test $(BINDIR)/$(CONFIG)/census_hash_table_test $(BINDIR)/$(CONFIG)/census_statistics_multiple_writers_circular_buffer_test $(BINDIR)/$(CONFIG)/census_statistics_multiple_writers_test $(BINDIR)/$(CONFIG)/census_statistics_performance_test $(BINDIR)/$(CONFIG)/census_statistics_quick_test $(BINDIR)/$(CONFIG)/census_statistics_small_log_test $(BINDIR)/$(CONFIG)/census_stub_test $(BINDIR)/$(CONFIG)/census_window_stats_test $(BINDIR)/$(CONFIG)/chttp2_status_conversion_test $(BINDIR)/$(CONFIG)/chttp2_stream_encoder_test $(BINDIR)/$(CONFIG)/chttp2_stream_map_test $(BINDIR)/$(CONFIG)/dualstack_socket_test $(BINDIR)/$(CONFIG)/fd_posix_test $(BINDIR)/$(CONFIG)/fling_client $(BINDIR)/$(CONFIG)/fling_server $(BINDIR)/$(CONFIG)/fling_stream_test $(BINDIR)/$(CONFIG)/fling_test $(BINDIR)/$(CONFIG)/gpr_cancellable_test $(BINDIR)/$(CONFIG)/gpr_cmdline_test $(BINDIR)/$(CONFIG)/gpr_env_test $(BINDIR)/$(CONFIG)/gpr_file_test $(BINDIR)/$(CONFIG)/gpr_histogram_test $(BINDIR)/$(CONFIG)/gpr_host_port_test $(BINDIR)/$(CONFIG)/gpr_log_test $(BINDIR)/$(CONFIG)/gpr_slice_buffer_test $(BINDIR)/$(CONFIG)/gpr_slice_test $(BINDIR)/$(CONFIG)/gpr_string_test $(BINDIR)/$(CONFIG)/gpr_sync_test $(BINDIR)/$(CONFIG)/gpr_thd_test $(BINDIR)/$(CONFIG)/gpr_time_test $(BINDIR)/$(CONFIG)/gpr_tls_test $(BINDIR)/$(CONFIG)/gpr_useful_test $(BINDIR)/$(CONFIG)/grpc_base64_test $(BINDIR)/$(CONFIG)/grpc_byte_buffer_reader_test $(BINDIR)/$(CONFIG)/grpc_channel_stack_test $(BINDIR)/$(CONFIG)/grpc_completion_queue_test $(BINDIR)/$(CONFIG)/grpc_credentials_test $(BINDIR)/$(CONFIG)/grpc_json_token_test $(BINDIR)/$(CONFIG)/grpc_stream_op_test $(BINDIR)/$(CONFIG)/hpack_parser_test $(BINDIR)/$(CONFIG)/hpack_table_test $(BINDIR)/$(CONFIG)/httpcli_format_request_test $(BINDIR)/$(CONFIG)/httpcli_parser_test $(BINDIR)/$(CONFIG)/httpcli_test $(BINDIR)/$(CONFIG)/json_rewrite $(BINDIR)/$(CONFIG)/json_rewrite_test $(BINDIR)/$(CONFIG)/json_test $(BINDIR)/$(CONFIG)/lame_client_test $(BINDIR)/$(CONFIG)/message_compress_test $(BINDIR)/$(CONFIG)/multi_init_test $(BINDIR)/$(CONFIG)/murmur_hash_test $(BINDIR)/$(CONFIG)/no_server_test $(BINDIR)/$(CONFIG)/poll_kick_posix_test $(BINDIR)/$(CONFIG)/resolve_address_test $(BINDIR)/$(CONFIG)/secure_endpoint_test $(BINDIR)/$(CONFIG)/sockaddr_utils_test $(BINDIR)/$(CONFIG)/tcp_client_posix_test $(BINDIR)/$(CONFIG)/tcp_posix_test $(BINDIR)/$(CONFIG)/tcp_server_posix_test $(BINDIR)/$(CONFIG)/time_averaged_stats_test $(BINDIR)/$(CONFIG)/time_test $(BINDIR)/$(CONFIG)/timeout_encoding_test $(BINDIR)/$(CONFIG)/timers_test $(BINDIR)/$(CONFIG)/transport_metadata_test $(BINDIR)/$(CONFIG)/transport_security_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_bad_hostname_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_cancel_after_accept_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_cancel_after_accept_and_writes_closed_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_cancel_after_invoke_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_cancel_before_invoke_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_cancel_in_a_vacuum_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_census_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_disappearing_server_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_early_server_shutdown_finishes_inflight_calls_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_early_server_shutdown_finishes_tags_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_empty_batch_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_graceful_server_shutdown_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_invoke_large_request_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_max_concurrent_streams_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_max_message_length_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_no_op_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_ping_pong_streaming_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_registered_call_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_request_response_with_binary_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_request_response_with_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_request_response_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_request_response_with_payload_and_call_creds_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_request_with_large_metadata_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_request_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_simple_delayed_request_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_fake_security_simple_request_with_high_initial_sequence_number_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_bad_hostname_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_cancel_after_accept_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_cancel_after_accept_and_writes_closed_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_cancel_after_invoke_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_cancel_before_invoke_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_cancel_in_a_vacuum_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_census_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_disappearing_server_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_early_server_shutdown_finishes_inflight_calls_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_early_server_shutdown_finishes_tags_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_empty_batch_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_graceful_server_shutdown_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_invoke_large_request_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_max_concurrent_streams_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_max_message_length_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_no_op_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_ping_pong_streaming_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_registered_call_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_request_response_with_binary_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_request_response_with_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_request_response_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_request_response_with_payload_and_call_creds_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_request_with_large_metadata_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_request_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_simple_delayed_request_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_simple_request_with_high_initial_sequence_number_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_bad_hostname_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_cancel_after_accept_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_cancel_after_accept_and_writes_closed_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_cancel_after_invoke_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_cancel_before_invoke_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_cancel_in_a_vacuum_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_census_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_disappearing_server_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_early_server_shutdown_finishes_inflight_calls_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_early_server_shutdown_finishes_tags_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_empty_batch_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_graceful_server_shutdown_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_invoke_large_request_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_max_concurrent_streams_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_max_message_length_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_no_op_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_ping_pong_streaming_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_registered_call_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_request_response_with_binary_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_request_response_with_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_request_response_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_request_response_with_payload_and_call_creds_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_request_with_large_metadata_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_request_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_simple_delayed_request_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_simple_request_with_high_initial_sequence_number_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_bad_hostname_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_after_accept_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_after_accept_and_writes_closed_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_after_invoke_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_before_invoke_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_cancel_in_a_vacuum_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_census_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_disappearing_server_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_early_server_shutdown_finishes_inflight_calls_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_early_server_shutdown_finishes_tags_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_empty_batch_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_graceful_server_shutdown_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_invoke_large_request_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_max_concurrent_streams_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_max_message_length_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_no_op_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_ping_pong_streaming_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_registered_call_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_request_response_with_binary_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_request_response_with_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_request_response_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_request_response_with_payload_and_call_creds_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_request_with_large_metadata_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_request_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_simple_delayed_request_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_fullstack_simple_request_with_high_initial_sequence_number_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_bad_hostname_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_after_accept_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_after_accept_and_writes_closed_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_after_invoke_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_before_invoke_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_cancel_in_a_vacuum_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_census_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_disappearing_server_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_early_server_shutdown_finishes_inflight_calls_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_early_server_shutdown_finishes_tags_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_empty_batch_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_graceful_server_shutdown_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_invoke_large_request_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_max_concurrent_streams_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_max_message_length_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_no_op_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_ping_pong_streaming_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_registered_call_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_response_with_binary_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_response_with_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_response_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_response_with_payload_and_call_creds_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_with_large_metadata_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_request_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_simple_delayed_request_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_simple_ssl_with_oauth2_fullstack_simple_request_with_high_initial_sequence_number_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_bad_hostname_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_cancel_after_accept_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_cancel_after_accept_and_writes_closed_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_cancel_after_invoke_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_cancel_before_invoke_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_cancel_in_a_vacuum_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_census_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_disappearing_server_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_early_server_shutdown_finishes_inflight_calls_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_early_server_shutdown_finishes_tags_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_empty_batch_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_graceful_server_shutdown_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_invoke_large_request_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_max_concurrent_streams_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_max_message_length_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_no_op_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_ping_pong_streaming_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_registered_call_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_request_response_with_binary_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_request_response_with_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_request_response_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_request_response_with_payload_and_call_creds_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_request_with_large_metadata_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_request_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_simple_delayed_request_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_simple_request_with_high_initial_sequence_number_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_bad_hostname_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_after_accept_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_after_accept_and_writes_closed_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_after_invoke_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_before_invoke_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_in_a_vacuum_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_census_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_disappearing_server_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_early_server_shutdown_finishes_inflight_calls_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_early_server_shutdown_finishes_tags_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_empty_batch_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_graceful_server_shutdown_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_invoke_large_request_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_max_concurrent_streams_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_max_message_length_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_no_op_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_ping_pong_streaming_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_registered_call_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_binary_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_metadata_and_payload_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_payload_and_call_creds_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_with_large_metadata_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_with_payload_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_simple_delayed_request_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_simple_request_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_simple_request_with_high_initial_sequence_number_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_bad_hostname_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_cancel_after_accept_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_cancel_after_accept_and_writes_closed_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_cancel_after_invoke_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_cancel_before_invoke_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_cancel_in_a_vacuum_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_census_simple_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_disappearing_server_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_early_server_shutdown_finishes_inflight_calls_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_early_server_shutdown_finishes_tags_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_empty_batch_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_graceful_server_shutdown_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_invoke_large_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_max_concurrent_streams_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_max_message_length_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_no_op_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_ping_pong_streaming_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_registered_call_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_request_response_with_binary_metadata_and_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_request_response_with_metadata_and_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_request_response_with_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_request_with_large_metadata_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_request_with_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_simple_delayed_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_simple_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_simple_request_with_high_initial_sequence_number_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_bad_hostname_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_cancel_after_accept_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_cancel_after_accept_and_writes_closed_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_cancel_after_invoke_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_cancel_before_invoke_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_cancel_in_a_vacuum_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_census_simple_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_disappearing_server_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_early_server_shutdown_finishes_inflight_calls_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_early_server_shutdown_finishes_tags_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_empty_batch_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_graceful_server_shutdown_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_invoke_large_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_max_concurrent_streams_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_max_message_length_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_no_op_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_ping_pong_streaming_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_registered_call_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_request_response_with_binary_metadata_and_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_request_response_with_metadata_and_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_request_response_with_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_request_with_large_metadata_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_request_with_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_simple_delayed_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_simple_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_fullstack_uds_posix_simple_request_with_high_initial_sequence_number_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_bad_hostname_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_cancel_after_accept_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_cancel_after_accept_and_writes_closed_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_cancel_after_invoke_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_cancel_before_invoke_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_cancel_in_a_vacuum_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_census_simple_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_disappearing_server_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_early_server_shutdown_finishes_inflight_calls_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_early_server_shutdown_finishes_tags_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_empty_batch_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_graceful_server_shutdown_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_invoke_large_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_max_concurrent_streams_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_max_message_length_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_no_op_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_ping_pong_streaming_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_registered_call_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_request_response_with_binary_metadata_and_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_request_response_with_metadata_and_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_request_response_with_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_request_with_large_metadata_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_request_with_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_simple_delayed_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_simple_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_simple_request_with_high_initial_sequence_number_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_bad_hostname_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_after_accept_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_after_accept_and_writes_closed_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_after_invoke_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_before_invoke_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_cancel_in_a_vacuum_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_census_simple_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_disappearing_server_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_early_server_shutdown_finishes_inflight_calls_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_early_server_shutdown_finishes_tags_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_empty_batch_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_graceful_server_shutdown_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_invoke_large_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_max_concurrent_streams_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_max_message_length_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_no_op_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_ping_pong_streaming_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_registered_call_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_binary_metadata_and_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_metadata_and_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_response_with_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_with_large_metadata_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_request_with_payload_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_simple_delayed_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_simple_request_unsecure_test $(BINDIR)/$(CONFIG)/chttp2_socket_pair_one_byte_at_a_time_simple_request_with_high_initial_sequence_number_unsecure_test
 
-buildtests_cxx: privatelibs_cxx $(BINDIR)/$(CONFIG)/async_end2end_test $(BINDIR)/$(CONFIG)/async_unary_ping_pong_test $(BINDIR)/$(CONFIG)/channel_arguments_test $(BINDIR)/$(CONFIG)/cli_call_test $(BINDIR)/$(CONFIG)/credentials_test $(BINDIR)/$(CONFIG)/cxx_time_test $(BINDIR)/$(CONFIG)/end2end_test $(BINDIR)/$(CONFIG)/generic_end2end_test $(BINDIR)/$(CONFIG)/grpc_cli $(BINDIR)/$(CONFIG)/interop_client $(BINDIR)/$(CONFIG)/interop_server $(BINDIR)/$(CONFIG)/interop_test $(BINDIR)/$(CONFIG)/mock_test $(BINDIR)/$(CONFIG)/qps_test $(BINDIR)/$(CONFIG)/status_test $(BINDIR)/$(CONFIG)/sync_streaming_ping_pong_test $(BINDIR)/$(CONFIG)/sync_unary_ping_pong_test $(BINDIR)/$(CONFIG)/thread_pool_test
+buildtests_cxx: privatelibs_cxx $(BINDIR)/$(CONFIG)/async_end2end_test $(BINDIR)/$(CONFIG)/async_unary_ping_pong_test $(BINDIR)/$(CONFIG)/channel_arguments_test $(BINDIR)/$(CONFIG)/cli_call_test $(BINDIR)/$(CONFIG)/credentials_test $(BINDIR)/$(CONFIG)/cxx_time_test $(BINDIR)/$(CONFIG)/end2end_test $(BINDIR)/$(CONFIG)/generic_end2end_test $(BINDIR)/$(CONFIG)/grpc_cli $(BINDIR)/$(CONFIG)/interop_client $(BINDIR)/$(CONFIG)/interop_server $(BINDIR)/$(CONFIG)/interop_test $(BINDIR)/$(CONFIG)/mock_test $(BINDIR)/$(CONFIG)/qps_test $(BINDIR)/$(CONFIG)/status_test $(BINDIR)/$(CONFIG)/sync_streaming_ping_pong_test $(BINDIR)/$(CONFIG)/sync_unary_ping_pong_test $(BINDIR)/$(CONFIG)/thread_pool_test $(BINDIR)/$(CONFIG)/thread_stress_test
 
 test: test_c test_cxx
 
@@ -1830,6 +1831,8 @@ test_cxx: buildtests_cxx
 	$(Q) $(BINDIR)/$(CONFIG)/status_test || ( echo test status_test failed ; exit 1 )
 	$(E) "[RUN]     Testing thread_pool_test"
 	$(Q) $(BINDIR)/$(CONFIG)/thread_pool_test || ( echo test thread_pool_test failed ; exit 1 )
+	$(E) "[RUN]     Testing thread_stress_test"
+	$(Q) $(BINDIR)/$(CONFIG)/thread_stress_test || ( echo test thread_stress_test failed ; exit 1 )
 
 
 test_python: static_c
@@ -7729,6 +7732,46 @@ endif
 endif
 
 
+THREAD_STRESS_TEST_SRC = \
+    test/cpp/end2end/thread_stress_test.cc \
+
+THREAD_STRESS_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(THREAD_STRESS_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL with ALPN.
+
+$(BINDIR)/$(CONFIG)/thread_stress_test: openssl_dep_error
+
+else
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.0.0+.
+
+$(BINDIR)/$(CONFIG)/thread_stress_test: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/thread_stress_test: $(PROTOBUF_DEP) $(THREAD_STRESS_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(THREAD_STRESS_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/thread_stress_test
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/cpp/end2end/thread_stress_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+deps_thread_stress_test: $(THREAD_STRESS_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(THREAD_STRESS_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 ifeq ($(NO_SECURE),true)
 
 # You can't build secure targets if you don't have OpenSSL with ALPN.
diff --git a/build.json b/build.json
index fa97b121d2..ba428c0ab3 100644
--- a/build.json
+++ b/build.json
@@ -2233,6 +2233,22 @@
         "gpr_test_util",
         "gpr"
       ]
+    },
+    {
+      "name": "thread_stress_test",
+      "build": "test",
+      "language": "c++",
+      "src": [
+        "test/cpp/end2end/thread_stress_test.cc"
+      ],
+      "deps": [
+        "grpc++_test_util",
+        "grpc_test_util",
+        "grpc++",
+        "grpc",
+        "gpr_test_util",
+        "gpr"
+      ]
     }
   ]
 }
diff --git a/include/grpc++/async_unary_call.h b/include/grpc++/async_unary_call.h
index 97cec77955..786f8c7184 100644
--- a/include/grpc++/async_unary_call.h
+++ b/include/grpc++/async_unary_call.h
@@ -60,9 +60,8 @@ class ClientAsyncResponseReader GRPC_FINAL
  public:
   ClientAsyncResponseReader(ChannelInterface* channel, CompletionQueue* cq,
                             const RpcMethod& method, ClientContext* context,
-                            const grpc::protobuf::Message& request, void* tag)
+                            const grpc::protobuf::Message& request)
       : context_(context), call_(channel->CreateCall(method, context, cq)) {
-    init_buf_.Reset(tag);
     init_buf_.AddSendInitialMetadata(&context->send_initial_metadata_);
     init_buf_.AddSendMessage(request);
     init_buf_.AddClientSendClose();
@@ -90,7 +89,7 @@ class ClientAsyncResponseReader GRPC_FINAL
  private:
   ClientContext* context_;
   Call call_;
-  CallOpBuffer init_buf_;
+  SneakyCallOpBuffer init_buf_;
   CallOpBuffer meta_buf_;
   CallOpBuffer finish_buf_;
 };
diff --git a/include/grpc++/impl/call.h b/include/grpc++/impl/call.h
index d76ef61dd2..aae199db1b 100644
--- a/include/grpc++/impl/call.h
+++ b/include/grpc++/impl/call.h
@@ -123,6 +123,14 @@ class CallOpBuffer : public CompletionQueueTag {
   bool* recv_closed_;
 };
 
+// SneakyCallOpBuffer does not post completions to the completion queue
+class SneakyCallOpBuffer GRPC_FINAL : public CallOpBuffer {
+ public:
+  bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE {
+    return CallOpBuffer::FinalizeResult(tag, status) && false;
+  }
+};
+
 // Channel and Server implement this to allow them to hook performing ops
 class CallHook {
  public:
diff --git a/src/compiler/cpp_generator.cc b/src/compiler/cpp_generator.cc
index 1ab85bad5c..084db17a30 100644
--- a/src/compiler/cpp_generator.cc
+++ b/src/compiler/cpp_generator.cc
@@ -160,13 +160,13 @@ void PrintHeaderClientMethodInterfaces(grpc::protobuf::io::Printer *printer,
           "::grpc::ClientAsyncResponseReaderInterface< $Response$>> "
           "Async$Method$(::grpc::ClientContext* context, "
           "const $Request$& request, "
-          "::grpc::CompletionQueue* cq, void* tag) {\n");
+          "::grpc::CompletionQueue* cq) {\n");
       printer->Indent();
       printer->Print(
           *vars,
           "return std::unique_ptr< "
           "::grpc::ClientAsyncResponseReaderInterface< $Response$>>("
-          "Async$Method$Raw(context, request, cq, tag));\n");
+          "Async$Method$Raw(context, request, cq));\n");
       printer->Outdent();
       printer->Print("}\n");
     } else if (ClientOnlyStreaming(method)) {
@@ -257,7 +257,7 @@ void PrintHeaderClientMethodInterfaces(grpc::protobuf::io::Printer *printer,
           "virtual ::grpc::ClientAsyncResponseReaderInterface< $Response$>* "
           "Async$Method$Raw(::grpc::ClientContext* context, "
           "const $Request$& request, "
-          "::grpc::CompletionQueue* cq, void* tag) = 0;\n");
+          "::grpc::CompletionQueue* cq) = 0;\n");
     } else if (ClientOnlyStreaming(method)) {
       printer->Print(
           *vars,
@@ -305,7 +305,6 @@ void PrintHeaderClientMethod(grpc::protobuf::io::Printer *printer,
       grpc_cpp_generator::ClassName(method->input_type(), true);
   (*vars)["Response"] =
       grpc_cpp_generator::ClassName(method->output_type(), true);
-
   if (is_public) {
     if (NoStreaming(method)) {
       printer->Print(
@@ -317,13 +316,13 @@ void PrintHeaderClientMethod(grpc::protobuf::io::Printer *printer,
           "std::unique_ptr< ::grpc::ClientAsyncResponseReader< $Response$>> "
           "Async$Method$(::grpc::ClientContext* context, "
           "const $Request$& request, "
-          "::grpc::CompletionQueue* cq, void* tag) {\n");
+          "::grpc::CompletionQueue* cq) {\n");
       printer->Indent();
       printer->Print(
           *vars,
           "return std::unique_ptr< "
           "::grpc::ClientAsyncResponseReader< $Response$>>("
-          "Async$Method$Raw(context, request, cq, tag));\n");
+          "Async$Method$Raw(context, request, cq));\n");
       printer->Outdent();
       printer->Print("}\n");
     } else if (ClientOnlyStreaming(method)) {
@@ -412,7 +411,7 @@ void PrintHeaderClientMethod(grpc::protobuf::io::Printer *printer,
           "::grpc::ClientAsyncResponseReader< $Response$>* "
           "Async$Method$Raw(::grpc::ClientContext* context, "
           "const $Request$& request, "
-          "::grpc::CompletionQueue* cq, void* tag) GRPC_OVERRIDE;\n");
+          "::grpc::CompletionQueue* cq) GRPC_OVERRIDE;\n");
     } else if (ClientOnlyStreaming(method)) {
       printer->Print(
           *vars,
@@ -739,13 +738,13 @@ void PrintSourceClientMethod(grpc::protobuf::io::Printer *printer,
         "::grpc::ClientAsyncResponseReader< $Response$>* "
         "$ns$$Service$::Stub::Async$Method$Raw(::grpc::ClientContext* context, "
         "const $Request$& request, "
-        "::grpc::CompletionQueue* cq, void* tag) {\n");
+        "::grpc::CompletionQueue* cq) {\n");
     printer->Print(*vars,
                    "  return new "
                    "::grpc::ClientAsyncResponseReader< $Response$>("
                    "channel(), cq, "
                    "rpcmethod_$Method$_, "
-                   "context, request, tag);\n"
+                   "context, request);\n"
                    "}\n\n");
   } else if (ClientOnlyStreaming(method)) {
     printer->Print(*vars,
diff --git a/src/ruby/bin/math_server.rb b/src/ruby/bin/math_server.rb
index 1bfe253b85..e46d9c671f 100755
--- a/src/ruby/bin/math_server.rb
+++ b/src/ruby/bin/math_server.rb
@@ -55,7 +55,7 @@ class Fibber
     return enum_for(:generator) unless block_given?
     idx, current, previous = 0, 1, 1
     until idx == @limit
-      if idx == 0 || idx == 1
+      if idx.zero? || idx == 1
         yield Math::Num.new(num: 1)
         idx += 1
         next
@@ -94,7 +94,7 @@ end
 # package. That practice should be avoided by defining real services.
 class Calculator < Math::Math::Service
   def div(div_args, _call)
-    if div_args.divisor == 0
+    if div_args.divisor.zero?
       # To send non-OK status handlers raise a StatusError with the code and
       # and detail they want sent as a Status.
       fail GRPC::StatusError.new(GRPC::Status::INVALID_ARGUMENT,
diff --git a/src/ruby/lib/grpc/core/time_consts.rb b/src/ruby/lib/grpc/core/time_consts.rb
index 7750cb0feb..e6dae7b08a 100644
--- a/src/ruby/lib/grpc/core/time_consts.rb
+++ b/src/ruby/lib/grpc/core/time_consts.rb
@@ -58,7 +58,7 @@ module GRPC
                "Cannot make an absolute deadline from #{timeish.inspect}")
         elsif timeish < 0
           TimeConsts::INFINITE_FUTURE
-        elsif timeish == 0
+        elsif timeish.zero?
           TimeConsts::ZERO
         else
           Time.now + timeish
diff --git a/src/ruby/lib/grpc/generic/rpc_server.rb b/src/ruby/lib/grpc/generic/rpc_server.rb
index 424719304e..de22466089 100644
--- a/src/ruby/lib/grpc/generic/rpc_server.rb
+++ b/src/ruby/lib/grpc/generic/rpc_server.rb
@@ -146,7 +146,7 @@ module GRPC
     def remove_current_thread
       @stop_mutex.synchronize do
         @workers.delete(Thread.current)
-        @stop_cond.signal if @workers.size == 0
+        @stop_cond.signal if @workers.size.zero?
       end
     end
 
@@ -364,7 +364,7 @@ module GRPC
     # - #running? returns true after this is called, until #stop cause the
     #   the server to stop.
     def run
-      if rpc_descs.size == 0
+      if rpc_descs.size.zero?
         logger.warn('did not run as no services were present')
         return
       end
@@ -455,7 +455,7 @@ module GRPC
       unless cls.include?(GenericService)
         fail "#{cls} must 'include GenericService'"
       end
-      if cls.rpc_descs.size == 0
+      if cls.rpc_descs.size.zero?
         fail "#{cls} should specify some rpc descriptions"
       end
       cls.assert_rpc_descs_have_methods
diff --git a/test/cpp/end2end/async_end2end_test.cc b/test/cpp/end2end/async_end2end_test.cc
index 0e5a3b05af..bf5540f706 100644
--- a/test/cpp/end2end/async_end2end_test.cc
+++ b/test/cpp/end2end/async_end2end_test.cc
@@ -140,14 +140,13 @@ class AsyncEnd2endTest : public ::testing::Test {
 
       send_request.set_message("Hello");
       std::unique_ptr<ClientAsyncResponseReader<EchoResponse> > response_reader(
-          stub_->AsyncEcho(&cli_ctx, send_request, &cli_cq_, tag(1)));
+          stub_->AsyncEcho(&cli_ctx, send_request, &cli_cq_));
 
       service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, &srv_cq_,
                            tag(2));
 
       server_ok(2);
       EXPECT_EQ(send_request.message(), recv_request.message());
-      client_ok(1);
 
       send_response.set_message(recv_request.message());
       response_writer.Finish(send_response, Status::OK, tag(3));
@@ -195,7 +194,7 @@ TEST_F(AsyncEnd2endTest, AsyncNextRpc) {
 
   send_request.set_message("Hello");
   std::unique_ptr<ClientAsyncResponseReader<EchoResponse> > response_reader(
-      stub_->AsyncEcho(&cli_ctx, send_request, &cli_cq_, tag(1)));
+      stub_->AsyncEcho(&cli_ctx, send_request, &cli_cq_));
 
   std::chrono::system_clock::time_point time_now(
       std::chrono::system_clock::now());
@@ -209,7 +208,6 @@ TEST_F(AsyncEnd2endTest, AsyncNextRpc) {
 
   verify_timed_ok(&srv_cq_, 2, true, time_limit);
   EXPECT_EQ(send_request.message(), recv_request.message());
-  verify_timed_ok(&cli_cq_, 1, true, time_limit);
 
   send_response.set_message(recv_request.message());
   response_writer.Finish(send_response, Status::OK, tag(3));
@@ -399,7 +397,7 @@ TEST_F(AsyncEnd2endTest, ClientInitialMetadataRpc) {
   cli_ctx.AddMetadata(meta2.first, meta2.second);
 
   std::unique_ptr<ClientAsyncResponseReader<EchoResponse> > response_reader(
-      stub_->AsyncEcho(&cli_ctx, send_request, &cli_cq_, tag(1)));
+      stub_->AsyncEcho(&cli_ctx, send_request, &cli_cq_));
 
   service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, &srv_cq_,
                        tag(2));
@@ -409,7 +407,6 @@ TEST_F(AsyncEnd2endTest, ClientInitialMetadataRpc) {
   EXPECT_EQ(meta1.second, client_initial_metadata.find(meta1.first)->second);
   EXPECT_EQ(meta2.second, client_initial_metadata.find(meta2.first)->second);
   EXPECT_EQ(static_cast<size_t>(2), client_initial_metadata.size());
-  client_ok(1);
 
   send_response.set_message(recv_request.message());
   response_writer.Finish(send_response, Status::OK, tag(3));
@@ -441,7 +438,7 @@ TEST_F(AsyncEnd2endTest, ServerInitialMetadataRpc) {
   std::pair<grpc::string, grpc::string> meta2("key2", "val2");
 
   std::unique_ptr<ClientAsyncResponseReader<EchoResponse> > response_reader(
-      stub_->AsyncEcho(&cli_ctx, send_request, &cli_cq_, tag(1)));
+      stub_->AsyncEcho(&cli_ctx, send_request, &cli_cq_));
 
   service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, &srv_cq_,
                        tag(2));
@@ -449,7 +446,6 @@ TEST_F(AsyncEnd2endTest, ServerInitialMetadataRpc) {
   EXPECT_EQ(send_request.message(), recv_request.message());
   srv_ctx.AddInitialMetadata(meta1.first, meta1.second);
   srv_ctx.AddInitialMetadata(meta2.first, meta2.second);
-  client_ok(1);
   response_writer.SendInitialMetadata(tag(3));
   server_ok(3);
 
@@ -489,7 +485,7 @@ TEST_F(AsyncEnd2endTest, ServerTrailingMetadataRpc) {
   std::pair<grpc::string, grpc::string> meta2("key2", "val2");
 
   std::unique_ptr<ClientAsyncResponseReader<EchoResponse> > response_reader(
-      stub_->AsyncEcho(&cli_ctx, send_request, &cli_cq_, tag(1)));
+      stub_->AsyncEcho(&cli_ctx, send_request, &cli_cq_));
 
   service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, &srv_cq_,
                        tag(2));
@@ -497,7 +493,6 @@ TEST_F(AsyncEnd2endTest, ServerTrailingMetadataRpc) {
   EXPECT_EQ(send_request.message(), recv_request.message());
   response_writer.SendInitialMetadata(tag(3));
   server_ok(3);
-  client_ok(1);
 
   send_response.set_message(recv_request.message());
   srv_ctx.AddTrailingMetadata(meta1.first, meta1.second);
@@ -550,7 +545,7 @@ TEST_F(AsyncEnd2endTest, MetadataRpc) {
   cli_ctx.AddMetadata(meta2.first, meta2.second);
 
   std::unique_ptr<ClientAsyncResponseReader<EchoResponse> > response_reader(
-      stub_->AsyncEcho(&cli_ctx, send_request, &cli_cq_, tag(1)));
+      stub_->AsyncEcho(&cli_ctx, send_request, &cli_cq_));
 
   service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, &srv_cq_,
                        tag(2));
@@ -560,7 +555,6 @@ TEST_F(AsyncEnd2endTest, MetadataRpc) {
   EXPECT_EQ(meta1.second, client_initial_metadata.find(meta1.first)->second);
   EXPECT_EQ(meta2.second, client_initial_metadata.find(meta2.first)->second);
   EXPECT_EQ(static_cast<size_t>(2), client_initial_metadata.size());
-  client_ok(1);
 
   srv_ctx.AddInitialMetadata(meta3.first, meta3.second);
   srv_ctx.AddInitialMetadata(meta4.first, meta4.second);
diff --git a/test/cpp/end2end/end2end_test.cc b/test/cpp/end2end/end2end_test.cc
index 0945ed269d..f35b16fe55 100644
--- a/test/cpp/end2end/end2end_test.cc
+++ b/test/cpp/end2end/end2end_test.cc
@@ -577,18 +577,6 @@ TEST_F(End2endTest, ClientCancelsBidi) {
   EXPECT_EQ(grpc::StatusCode::CANCELLED, s.code());
 }
 
-TEST_F(End2endTest, ThreadStress) {
-  ResetStub();
-  std::vector<std::thread*> threads;
-  for (int i = 0; i < 100; ++i) {
-    threads.push_back(new std::thread(SendRpc, stub_.get(), 1000));
-  }
-  for (int i = 0; i < 100; ++i) {
-    threads[i]->join();
-    delete threads[i];
-  }
-}
-
 TEST_F(End2endTest, RpcMaxMessageSize) {
   ResetStub();
   EchoRequest request;
diff --git a/test/cpp/end2end/mock_test.cc b/test/cpp/end2end/mock_test.cc
index a4b2ee3ca5..0226da672c 100644
--- a/test/cpp/end2end/mock_test.cc
+++ b/test/cpp/end2end/mock_test.cc
@@ -119,8 +119,8 @@ class MockStub : public TestService::StubInterface {
 
  private:
   ClientAsyncResponseReaderInterface<EchoResponse>* AsyncEchoRaw(
-      ClientContext* context, const EchoRequest& request, CompletionQueue* cq,
-      void* tag) GRPC_OVERRIDE {
+      ClientContext* context, const EchoRequest& request,
+      CompletionQueue* cq) GRPC_OVERRIDE {
     return nullptr;
   }
   ClientWriterInterface<EchoRequest>* RequestStreamRaw(
@@ -151,8 +151,8 @@ class MockStub : public TestService::StubInterface {
     return nullptr;
   }
   ClientAsyncResponseReaderInterface<EchoResponse>* AsyncUnimplementedRaw(
-      ClientContext* context, const EchoRequest& request, CompletionQueue* cq,
-      void* tag) GRPC_OVERRIDE {
+      ClientContext* context, const EchoRequest& request,
+      CompletionQueue* cq) GRPC_OVERRIDE {
     return nullptr;
   }
 };
diff --git a/test/cpp/end2end/thread_stress_test.cc b/test/cpp/end2end/thread_stress_test.cc
new file mode 100644
index 0000000000..12656128c0
--- /dev/null
+++ b/test/cpp/end2end/thread_stress_test.cc
@@ -0,0 +1,242 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <thread>
+
+#include "test/core/util/port.h"
+#include "test/core/util/test_config.h"
+#include "test/cpp/util/echo_duplicate.grpc.pb.h"
+#include "test/cpp/util/echo.grpc.pb.h"
+#include "src/cpp/server/thread_pool.h"
+#include <grpc++/channel_arguments.h>
+#include <grpc++/channel_interface.h>
+#include <grpc++/client_context.h>
+#include <grpc++/create_channel.h>
+#include <grpc++/credentials.h>
+#include <grpc++/server.h>
+#include <grpc++/server_builder.h>
+#include <grpc++/server_context.h>
+#include <grpc++/server_credentials.h>
+#include <grpc++/status.h>
+#include <grpc++/stream.h>
+#include <grpc++/time.h>
+#include <gtest/gtest.h>
+
+#include <grpc/grpc.h>
+#include <grpc/support/thd.h>
+#include <grpc/support/time.h>
+
+using grpc::cpp::test::util::EchoRequest;
+using grpc::cpp::test::util::EchoResponse;
+using std::chrono::system_clock;
+
+namespace grpc {
+namespace testing {
+
+namespace {
+
+// When echo_deadline is requested, deadline seen in the ServerContext is set in
+// the response in seconds.
+void MaybeEchoDeadline(ServerContext* context, const EchoRequest* request,
+                       EchoResponse* response) {
+  if (request->has_param() && request->param().echo_deadline()) {
+    gpr_timespec deadline = gpr_inf_future;
+    if (context->deadline() != system_clock::time_point::max()) {
+      Timepoint2Timespec(context->deadline(), &deadline);
+    }
+    response->mutable_param()->set_request_deadline(deadline.tv_sec);
+  }
+}
+
+}  // namespace
+
+class TestServiceImpl : public ::grpc::cpp::test::util::TestService::Service {
+ public:
+  TestServiceImpl() : signal_client_(false) {}
+
+  Status Echo(ServerContext* context, const EchoRequest* request,
+              EchoResponse* response) GRPC_OVERRIDE {
+    response->set_message(request->message());
+    MaybeEchoDeadline(context, request, response);
+    if (request->has_param() && request->param().client_cancel_after_us()) {
+      {
+        std::unique_lock<std::mutex> lock(mu_);
+        signal_client_ = true;
+      }
+      while (!context->IsCancelled()) {
+        std::this_thread::sleep_for(std::chrono::microseconds(
+            request->param().client_cancel_after_us()));
+      }
+      return Status::Cancelled;
+    } else if (request->has_param() &&
+               request->param().server_cancel_after_us()) {
+      std::this_thread::sleep_for(
+          std::chrono::microseconds(request->param().server_cancel_after_us()));
+      return Status::Cancelled;
+    } else {
+      EXPECT_FALSE(context->IsCancelled());
+    }
+    return Status::OK;
+  }
+
+  // Unimplemented is left unimplemented to test the returned error.
+
+  Status RequestStream(ServerContext* context,
+                       ServerReader<EchoRequest>* reader,
+                       EchoResponse* response) GRPC_OVERRIDE {
+    EchoRequest request;
+    response->set_message("");
+    while (reader->Read(&request)) {
+      response->mutable_message()->append(request.message());
+    }
+    return Status::OK;
+  }
+
+  // Return 3 messages.
+  // TODO(yangg) make it generic by adding a parameter into EchoRequest
+  Status ResponseStream(ServerContext* context, const EchoRequest* request,
+                        ServerWriter<EchoResponse>* writer) GRPC_OVERRIDE {
+    EchoResponse response;
+    response.set_message(request->message() + "0");
+    writer->Write(response);
+    response.set_message(request->message() + "1");
+    writer->Write(response);
+    response.set_message(request->message() + "2");
+    writer->Write(response);
+
+    return Status::OK;
+  }
+
+  Status BidiStream(ServerContext* context,
+                    ServerReaderWriter<EchoResponse, EchoRequest>* stream)
+      GRPC_OVERRIDE {
+    EchoRequest request;
+    EchoResponse response;
+    while (stream->Read(&request)) {
+      gpr_log(GPR_INFO, "recv msg %s", request.message().c_str());
+      response.set_message(request.message());
+      stream->Write(response);
+    }
+    return Status::OK;
+  }
+
+  bool signal_client() {
+    std::unique_lock<std::mutex> lock(mu_);
+    return signal_client_;
+  }
+
+ private:
+  bool signal_client_;
+  std::mutex mu_;
+};
+
+class TestServiceImplDupPkg
+    : public ::grpc::cpp::test::util::duplicate::TestService::Service {
+ public:
+  Status Echo(ServerContext* context, const EchoRequest* request,
+              EchoResponse* response) GRPC_OVERRIDE {
+    response->set_message("no package");
+    return Status::OK;
+  }
+};
+
+class End2endTest : public ::testing::Test {
+ protected:
+  End2endTest() : kMaxMessageSize_(8192), thread_pool_(2) {}
+
+  void SetUp() GRPC_OVERRIDE {
+    int port = grpc_pick_unused_port_or_die();
+    server_address_ << "localhost:" << port;
+    // Setup server
+    ServerBuilder builder;
+    builder.AddListeningPort(server_address_.str(),
+                             InsecureServerCredentials());
+    builder.RegisterService(&service_);
+    builder.SetMaxMessageSize(
+        kMaxMessageSize_);  // For testing max message size.
+    builder.RegisterService(&dup_pkg_service_);
+    builder.SetThreadPool(&thread_pool_);
+    server_ = builder.BuildAndStart();
+  }
+
+  void TearDown() GRPC_OVERRIDE { server_->Shutdown(); }
+
+  void ResetStub() {
+    std::shared_ptr<ChannelInterface> channel = CreateChannel(
+        server_address_.str(), InsecureCredentials(), ChannelArguments());
+    stub_ = std::move(grpc::cpp::test::util::TestService::NewStub(channel));
+  }
+
+  std::unique_ptr<grpc::cpp::test::util::TestService::Stub> stub_;
+  std::unique_ptr<Server> server_;
+  std::ostringstream server_address_;
+  const int kMaxMessageSize_;
+  TestServiceImpl service_;
+  TestServiceImplDupPkg dup_pkg_service_;
+  ThreadPool thread_pool_;
+};
+
+static void SendRpc(grpc::cpp::test::util::TestService::Stub* stub,
+                    int num_rpcs) {
+  EchoRequest request;
+  EchoResponse response;
+  request.set_message("Hello");
+
+  for (int i = 0; i < num_rpcs; ++i) {
+    ClientContext context;
+    Status s = stub->Echo(&context, request, &response);
+    EXPECT_EQ(response.message(), request.message());
+    EXPECT_TRUE(s.IsOk());
+  }
+}
+
+TEST_F(End2endTest, ThreadStress) {
+  ResetStub();
+  std::vector<std::thread*> threads;
+  for (int i = 0; i < 100; ++i) {
+    threads.push_back(new std::thread(SendRpc, stub_.get(), 1000));
+  }
+  for (int i = 0; i < 100; ++i) {
+    threads[i]->join();
+    delete threads[i];
+  }
+}
+
+}  // namespace testing
+}  // namespace grpc
+
+int main(int argc, char** argv) {
+  grpc_test_init(argc, argv);
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
diff --git a/test/cpp/qps/client_async.cc b/test/cpp/qps/client_async.cc
index 0aec1b1a57..e3ab57728d 100644
--- a/test/cpp/qps/client_async.cc
+++ b/test/cpp/qps/client_async.cc
@@ -75,19 +75,20 @@ class ClientRpcContextUnaryImpl : public ClientRpcContext {
       TestService::Stub* stub, const RequestType& req,
       std::function<
           std::unique_ptr<grpc::ClientAsyncResponseReader<ResponseType>>(
-              TestService::Stub*, grpc::ClientContext*, const RequestType&,
-              void*)> start_req,
+              TestService::Stub*, grpc::ClientContext*, const RequestType&)>
+          start_req,
       std::function<void(grpc::Status, ResponseType*)> on_done)
       : context_(),
         stub_(stub),
         req_(req),
         response_(),
-        next_state_(&ClientRpcContextUnaryImpl::ReqSent),
+        next_state_(&ClientRpcContextUnaryImpl::RespDone),
         callback_(on_done),
         start_req_(start_req),
         start_(Timer::Now()),
-        response_reader_(
-            start_req(stub_, &context_, req_, ClientRpcContext::tag(this))) {}
+        response_reader_(start_req(stub_, &context_, req_)) {
+    response_reader_->Finish(&response_, &status_, ClientRpcContext::tag(this));
+  }
   ~ClientRpcContextUnaryImpl() GRPC_OVERRIDE {}
   bool RunNextState(bool ok, Histogram* hist) GRPC_OVERRIDE {
     bool ret = (this->*next_state_)(ok);
@@ -102,11 +103,6 @@ class ClientRpcContextUnaryImpl : public ClientRpcContext {
   }
 
  private:
-  bool ReqSent(bool) {
-    next_state_ = &ClientRpcContextUnaryImpl::RespDone;
-    response_reader_->Finish(&response_, &status_, ClientRpcContext::tag(this));
-    return true;
-  }
   bool RespDone(bool) {
     next_state_ = &ClientRpcContextUnaryImpl::DoCallBack;
     return false;
@@ -122,8 +118,7 @@ class ClientRpcContextUnaryImpl : public ClientRpcContext {
   bool (ClientRpcContextUnaryImpl::*next_state_)(bool);
   std::function<void(grpc::Status, ResponseType*)> callback_;
   std::function<std::unique_ptr<grpc::ClientAsyncResponseReader<ResponseType>>(
-      TestService::Stub*, grpc::ClientContext*, const RequestType&, void*)>
-      start_req_;
+      TestService::Stub*, grpc::ClientContext*, const RequestType&)> start_req_;
   grpc::Status status_;
   double start_;
   std::unique_ptr<grpc::ClientAsyncResponseReader<ResponseType>>
@@ -198,8 +193,8 @@ private:
                        const SimpleRequest& req) {
     auto check_done = [](grpc::Status s, SimpleResponse* response) {};
     auto start_req = [cq](TestService::Stub* stub, grpc::ClientContext* ctx,
-                          const SimpleRequest& request, void* tag) {
-      return stub->AsyncUnaryCall(ctx, request, cq, tag);
+                          const SimpleRequest& request) {
+      return stub->AsyncUnaryCall(ctx, request, cq);
     };
     new ClientRpcContextUnaryImpl<SimpleRequest, SimpleResponse>(
         stub, req, start_req, check_done);
diff --git a/tools/profile_analyzer/profile_analyzer.py b/tools/profile_analyzer/profile_analyzer.py
index 00b1079466..a78f84e5e6 100755
--- a/tools/profile_analyzer/profile_analyzer.py
+++ b/tools/profile_analyzer/profile_analyzer.py
@@ -39,8 +39,8 @@ Usage:
 
 import collections
 import itertools
+import math
 import re
-import sys
 
 # Create a regex to parse output of the C core basic profiler,
 # as defined in src/core/profiling/basic_timers.c.
@@ -64,19 +64,68 @@ class ImportantMark(object):
   def entry(self):
     return self._entry
 
-  def append_post_entry(self, entry):
-    if self._n > 0:
-      self._post_stack.append(entry)
+  @property
+  def max_depth(self):
+    return self._n
+
+  def append_post_entry(self, post_entry):
+    if self._n > 0 and post_entry.thread == self._entry.thread:
+      self._post_stack.append(post_entry)
       self._n -= 1
 
   def get_deltas(self):
     pre_and_post_stacks = itertools.chain(self._pre_stack, self._post_stack)
     return collections.OrderedDict((stack_entry,
-                                   (self._entry.time - stack_entry.time))
+                                   abs(self._entry.time - stack_entry.time))
                                    for stack_entry in pre_and_post_stacks)
 
-def entries():
-  for line in sys.stdin:
+
+def print_block_statistics(block_times):
+  print '{:<12s}  {:>12s} {:>12s} {:>12s} {:>12s}'.format(
+          'Block tag', '50th p.', '90th p.', '95th p.', '99th p.')
+  for tag, tag_times in sorted(block_times.iteritems()):
+    times = sorted(tag_times)
+    print '{:<12d}: {:>12.3f} {:>12.3f} {:>12.3f} {:>12.3f}'.format(
+            tag, percentile(times, 50), percentile(times, 90),
+            percentile(times, 95), percentile(times, 99))
+  print
+
+def print_grouped_imark_statistics(group_key, imarks_group):
+  values = collections.OrderedDict()
+  for imark in imarks_group:
+    deltas = imark.get_deltas()
+    for relative_entry, time_delta_us in deltas.iteritems():
+      key = '{tag} {type} ({file}:{line})'.format(**relative_entry._asdict())
+      l = values.setdefault(key, list())
+      l.append(time_delta_us)
+
+  print group_key
+  print '{:<50s}  {:>12s} {:>12s} {:>12s} {:>12s}'.format(
+        'Relative mark', '50th p.', '90th p.', '95th p.', '99th p.')
+  for key, time_values in values.iteritems():
+    time_values = sorted(time_values)
+    print '{:<50s}: {:>12.3f} {:>12.3f} {:>12.3f} {:>12.3f}'.format(
+          key, percentile(time_values, 50), percentile(time_values, 90),
+          percentile(time_values, 95), percentile(time_values, 99))
+  print
+
+def percentile(vals, percent):
+  """ Calculates the interpolated percentile given a sorted sequence and a
+  percent (in the usual 0-100 range)."""
+  assert vals, "Empty input sequence."
+  percent /= 100.0
+  k = (len(vals)-1) * percent
+  f = math.floor(k)
+  c = math.ceil(k)
+  if f == c:
+      return vals[int(k)]
+  # else, interpolate
+  d0 = vals[int(f)] * (c-k)
+  d1 = vals[int(c)] * (k-f)
+  return d0 + d1
+
+def entries(f):
+  for line in f:
     m = _RE_LINE.match(line)
     if not m: continue
     yield Entry(time=float(m.group(1)),
@@ -87,53 +136,53 @@ def entries():
                 file=m.group(6),
                 line=m.group(7))
 
-threads = collections.defaultdict(lambda: collections.defaultdict(list))
-times = collections.defaultdict(list)
-
-# Indexed by the mark's tag. Items in the value list correspond to the mark in
-# different stack situations.
-important_marks = collections.defaultdict(list)
-
-for entry in entries():
-  thread = threads[entry.thread]
-  if entry.type == '{':
-    thread[entry.tag].append(entry)
-  if entry.type == '!':
-    # Save a snapshot of the current stack inside a new ImportantMark instance.
-    # Get all entries with type '{' from "thread".
-    stack = [e for entries_for_tag in thread.values()
-               for e in entries_for_tag if e.type == '{']
-    important_marks[entry.tag].append(ImportantMark(entry, stack))
-  elif entry.type == '}':
-    last = thread[entry.tag].pop()
-    times[entry.tag].append(entry.time - last.time)
-    # Update accounting for important marks.
-    for imarks_for_tag in important_marks.itervalues():
-      for imark in imarks_for_tag:
-        imark.append_post_entry(entry)
-
-def percentile(vals, pct):
-  return sorted(vals)[int(len(vals) * pct / 100.0)]
-
-print 'tag 50%/90%/95%/99% us'
-for tag in sorted(times.keys()):
-  vals = times[tag]
-  print '%d %.2f/%.2f/%.2f/%.2f' % (tag,
-                                    percentile(vals, 50),
-                                    percentile(vals, 90),
-                                    percentile(vals, 95),
-                                    percentile(vals, 99))
-
-print
-print 'Important marks:'
-print '================'
-for tag, imark_for_tag in important_marks.iteritems():
-  for imark in imarks_for_tag:
-    deltas = imark.get_deltas()
-    print '{tag} @ {file}:{line}'.format(**imark.entry._asdict())
-    for entry, time_delta_us in deltas.iteritems():
-      format_dict = entry._asdict()
-      format_dict['time_delta_us']  = time_delta_us
-      print '{tag} {type} ({file}:{line}): {time_delta_us:12.3f} us'.format(
-          **format_dict)
-    print
+def main(f):
+  percentiles = (50, 90, 95, 99)
+  threads = collections.defaultdict(lambda: collections.defaultdict(list))
+  times = collections.defaultdict(list)
+  important_marks = collections.defaultdict(list)
+  stack_depth = collections.defaultdict(int)
+  for entry in entries(f):
+    thread = threads[entry.thread]
+    if entry.type == '{':
+      thread[entry.tag].append(entry)
+      stack_depth[entry.thread] += 1
+    if entry.type == '!':
+      # Save a snapshot of the current stack inside a new ImportantMark instance.
+      # Get all entries _for any tag in the thread_.
+      stack = [e for entries_for_tag in thread.itervalues()
+                 for e in entries_for_tag]
+      imark_group_key = '{tag}/{thread}@{file}:{line}'.format(**entry._asdict())
+      important_marks[imark_group_key].append(ImportantMark(entry, stack))
+    elif entry.type == '}':
+      last = thread[entry.tag].pop()
+      times[entry.tag].append(entry.time - last.time)
+      # only access the last "depth" imarks for the tag.
+      depth = stack_depth[entry.thread]
+      for imarks_group in important_marks.itervalues():
+        for imark in imarks_group[-depth:]:
+          # if at a '}' deeper than where the current "imark" was found, ignore.
+          if depth > imark.max_depth: continue
+          imark.append_post_entry(entry)
+      stack_depth[entry.thread] -= 1
+
+  print
+  print 'Block marks:'
+  print '============'
+  print_block_statistics(times)
+
+  print
+  print 'Important marks:'
+  print '================'
+  for group_key, imarks_group in important_marks.iteritems():
+    print_grouped_imark_statistics(group_key, imarks_group)
+
+
+if __name__ == '__main__':
+  # If invoked without arguments, read off sys.stdin. If one argument is given,
+  # take it as a file name and open it for reading.
+  import sys
+  f = sys.stdin
+  if len(sys.argv) == 2:
+    f = open(sys.argv[1], 'r')
+  main(f)
diff --git a/tools/run_tests/tests.json b/tools/run_tests/tests.json
index 17429f0240..e0b7ef16fb 100644
--- a/tools/run_tests/tests.json
+++ b/tools/run_tests/tests.json
@@ -688,6 +688,15 @@
   }, 
   {
     "flaky": false, 
+    "language": "c++", 
+    "name": "thread_stress_test", 
+    "platforms": [
+      "windows", 
+      "posix"
+    ]
+  }, 
+  {
+    "flaky": false, 
     "language": "c", 
     "name": "chttp2_fake_security_bad_hostname_test", 
     "platforms": [