Merge pull request #9511 from ctiller/assert_writes

Add a test verifying number of writes per RPC is reasonable

53 files changed, 1855 insertions, 279 deletions

diff --git a/BUILD b/BUILD
index 92847a7b4e..58971ff8e3 100644
--- a/BUILD
+++ b/BUILD
@@ -526,6 +526,7 @@ grpc_cc_library(
         "src/core/lib/transport/metadata.c",
         "src/core/lib/transport/metadata_batch.c",
         "src/core/lib/transport/pid_controller.c",
+        "src/core/lib/transport/bdp_estimator.c",
         "src/core/lib/transport/service_config.c",
         "src/core/lib/transport/static_metadata.c",
         "src/core/lib/transport/status_conversion.c",
@@ -633,6 +634,7 @@ grpc_cc_library(
         "src/core/lib/transport/metadata.h",
         "src/core/lib/transport/metadata_batch.h",
         "src/core/lib/transport/pid_controller.h",
+        "src/core/lib/transport/bdp_estimator.h",
         "src/core/lib/transport/service_config.h",
         "src/core/lib/transport/static_metadata.h",
         "src/core/lib/transport/status_conversion.h",
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3b320db1b3..d52e199842 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -333,6 +333,7 @@ add_dependencies(buildtests_c algorithm_test)
 add_dependencies(buildtests_c alloc_test)
 add_dependencies(buildtests_c alpn_test)
 add_dependencies(buildtests_c bad_server_response_test)
+add_dependencies(buildtests_c bdp_estimator_test)
 add_dependencies(buildtests_c bin_decoder_test)
 add_dependencies(buildtests_c bin_encoder_test)
 add_dependencies(buildtests_c census_context_test)
@@ -639,6 +640,9 @@ endif()
 add_dependencies(buildtests_cxx stress_test)
 add_dependencies(buildtests_cxx thread_manager_test)
 add_dependencies(buildtests_cxx thread_stress_test)
+if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
+add_dependencies(buildtests_cxx writes_per_rpc_test)
+endif()
 
 add_custom_target(buildtests
   DEPENDS buildtests_c buildtests_cxx)
@@ -897,6 +901,7 @@ add_library(grpc
   src/core/lib/surface/server.c
   src/core/lib/surface/validate_metadata.c
   src/core/lib/surface/version.c
+  src/core/lib/transport/bdp_estimator.c
   src/core/lib/transport/byte_stream.c
   src/core/lib/transport/connectivity_state.c
   src/core/lib/transport/error_utils.c
@@ -1191,6 +1196,7 @@ add_library(grpc_cronet
   src/core/lib/surface/server.c
   src/core/lib/surface/validate_metadata.c
   src/core/lib/surface/version.c
+  src/core/lib/transport/bdp_estimator.c
   src/core/lib/transport/byte_stream.c
   src/core/lib/transport/connectivity_state.c
   src/core/lib/transport/error_utils.c
@@ -1476,6 +1482,7 @@ add_library(grpc_test_util
   src/core/lib/surface/server.c
   src/core/lib/surface/validate_metadata.c
   src/core/lib/surface/version.c
+  src/core/lib/transport/bdp_estimator.c
   src/core/lib/transport/byte_stream.c
   src/core/lib/transport/connectivity_state.c
   src/core/lib/transport/error_utils.c
@@ -1699,6 +1706,7 @@ add_library(grpc_unsecure
   src/core/lib/surface/server.c
   src/core/lib/surface/validate_metadata.c
   src/core/lib/surface/version.c
+  src/core/lib/transport/bdp_estimator.c
   src/core/lib/transport/byte_stream.c
   src/core/lib/transport/connectivity_state.c
   src/core/lib/transport/error_utils.c
@@ -2244,6 +2252,7 @@ add_library(grpc++_cronet
   src/core/lib/surface/server.c
   src/core/lib/surface/validate_metadata.c
   src/core/lib/surface/version.c
+  src/core/lib/transport/bdp_estimator.c
   src/core/lib/transport/byte_stream.c
   src/core/lib/transport/connectivity_state.c
   src/core/lib/transport/error_utils.c
@@ -3705,6 +3714,33 @@ target_link_libraries(bad_server_response_test
 endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
 
+add_executable(bdp_estimator_test
+  test/core/transport/bdp_estimator_test.c
+)
+
+
+target_include_directories(bdp_estimator_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 ${CMAKE_CURRENT_BINARY_DIR}/third_party/gflags/include
+)
+
+target_link_libraries(bdp_estimator_test
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpc_test_util
+  grpc
+  gpr_test_util
+  gpr
+)
+
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
+
 add_executable(bin_decoder_test
   test/core/transport/chttp2/bin_decoder_test.c
 )
@@ -9209,6 +9245,43 @@ target_link_libraries(thread_stress_test
 
 endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
+if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
+
+add_executable(writes_per_rpc_test
+  test/cpp/performance/writes_per_rpc_test.cc
+  third_party/googletest/src/gtest-all.cc
+)
+
+
+target_include_directories(writes_per_rpc_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 ${CMAKE_CURRENT_BINARY_DIR}/third_party/gflags/include
+  PRIVATE third_party/googletest/include
+  PRIVATE third_party/googletest
+  PRIVATE ${_gRPC_PROTO_GENS_DIR}
+)
+
+target_link_libraries(writes_per_rpc_test
+  ${_gRPC_PROTOBUF_LIBRARIES}
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpc++_test_util
+  grpc_test_util
+  grpc++
+  grpc
+  gpr_test_util
+  gpr
+  ${_gRPC_GFLAGS_LIBRARIES}
+)
+
+endif()
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
 
 add_executable(public_headers_must_be_c89
   test/core/surface/public_headers_must_be_c89.c
diff --git a/Makefile b/Makefile
index 0d1d64cdcd..0413cc0e00 100644
--- a/Makefile
+++ b/Makefile
@@ -899,6 +899,7 @@ alloc_test: $(BINDIR)/$(CONFIG)/alloc_test
 alpn_test: $(BINDIR)/$(CONFIG)/alpn_test
 api_fuzzer: $(BINDIR)/$(CONFIG)/api_fuzzer
 bad_server_response_test: $(BINDIR)/$(CONFIG)/bad_server_response_test
+bdp_estimator_test: $(BINDIR)/$(CONFIG)/bdp_estimator_test
 bin_decoder_test: $(BINDIR)/$(CONFIG)/bin_decoder_test
 bin_encoder_test: $(BINDIR)/$(CONFIG)/bin_encoder_test
 census_context_test: $(BINDIR)/$(CONFIG)/census_context_test
@@ -1090,6 +1091,7 @@ streaming_throughput_test: $(BINDIR)/$(CONFIG)/streaming_throughput_test
 stress_test: $(BINDIR)/$(CONFIG)/stress_test
 thread_manager_test: $(BINDIR)/$(CONFIG)/thread_manager_test
 thread_stress_test: $(BINDIR)/$(CONFIG)/thread_stress_test
+writes_per_rpc_test: $(BINDIR)/$(CONFIG)/writes_per_rpc_test
 public_headers_must_be_c89: $(BINDIR)/$(CONFIG)/public_headers_must_be_c89
 boringssl_aes_test: $(BINDIR)/$(CONFIG)/boringssl_aes_test
 boringssl_asn1_test: $(BINDIR)/$(CONFIG)/boringssl_asn1_test
@@ -1259,6 +1261,7 @@ buildtests_c: privatelibs_c \
   $(BINDIR)/$(CONFIG)/alloc_test \
   $(BINDIR)/$(CONFIG)/alpn_test \
   $(BINDIR)/$(CONFIG)/bad_server_response_test \
+  $(BINDIR)/$(CONFIG)/bdp_estimator_test \
   $(BINDIR)/$(CONFIG)/bin_decoder_test \
   $(BINDIR)/$(CONFIG)/bin_encoder_test \
   $(BINDIR)/$(CONFIG)/census_context_test \
@@ -1485,6 +1488,7 @@ buildtests_cxx: privatelibs_cxx \
   $(BINDIR)/$(CONFIG)/stress_test \
   $(BINDIR)/$(CONFIG)/thread_manager_test \
   $(BINDIR)/$(CONFIG)/thread_stress_test \
+  $(BINDIR)/$(CONFIG)/writes_per_rpc_test \
   $(BINDIR)/$(CONFIG)/boringssl_aes_test \
   $(BINDIR)/$(CONFIG)/boringssl_asn1_test \
   $(BINDIR)/$(CONFIG)/boringssl_base64_test \
@@ -1587,6 +1591,7 @@ buildtests_cxx: privatelibs_cxx \
   $(BINDIR)/$(CONFIG)/stress_test \
   $(BINDIR)/$(CONFIG)/thread_manager_test \
   $(BINDIR)/$(CONFIG)/thread_stress_test \
+  $(BINDIR)/$(CONFIG)/writes_per_rpc_test \
 
 endif
 
@@ -1606,6 +1611,8 @@ test_c: buildtests_c
 	$(Q) $(BINDIR)/$(CONFIG)/alpn_test || ( echo test alpn_test failed ; exit 1 )
 	$(E) "[RUN]     Testing bad_server_response_test"
 	$(Q) $(BINDIR)/$(CONFIG)/bad_server_response_test || ( echo test bad_server_response_test failed ; exit 1 )
+	$(E) "[RUN]     Testing bdp_estimator_test"
+	$(Q) $(BINDIR)/$(CONFIG)/bdp_estimator_test || ( echo test bdp_estimator_test failed ; exit 1 )
 	$(E) "[RUN]     Testing bin_decoder_test"
 	$(Q) $(BINDIR)/$(CONFIG)/bin_decoder_test || ( echo test bin_decoder_test failed ; exit 1 )
 	$(E) "[RUN]     Testing bin_encoder_test"
@@ -1918,6 +1925,8 @@ test_cxx: buildtests_cxx
 	$(Q) $(BINDIR)/$(CONFIG)/thread_manager_test || ( echo test thread_manager_test failed ; exit 1 )
 	$(E) "[RUN]     Testing thread_stress_test"
 	$(Q) $(BINDIR)/$(CONFIG)/thread_stress_test || ( echo test thread_stress_test failed ; exit 1 )
+	$(E) "[RUN]     Testing writes_per_rpc_test"
+	$(Q) $(BINDIR)/$(CONFIG)/writes_per_rpc_test || ( echo test writes_per_rpc_test failed ; exit 1 )
 
 
 flaky_test_cxx: buildtests_cxx
@@ -2729,6 +2738,7 @@ LIBGRPC_SRC = \
     src/core/lib/surface/server.c \
     src/core/lib/surface/validate_metadata.c \
     src/core/lib/surface/version.c \
+    src/core/lib/transport/bdp_estimator.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
     src/core/lib/transport/error_utils.c \
@@ -3037,6 +3047,7 @@ LIBGRPC_CRONET_SRC = \
     src/core/lib/surface/server.c \
     src/core/lib/surface/validate_metadata.c \
     src/core/lib/surface/version.c \
+    src/core/lib/transport/bdp_estimator.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
     src/core/lib/transport/error_utils.c \
@@ -3336,6 +3347,7 @@ LIBGRPC_TEST_UTIL_SRC = \
     src/core/lib/surface/server.c \
     src/core/lib/surface/validate_metadata.c \
     src/core/lib/surface/version.c \
+    src/core/lib/transport/bdp_estimator.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
     src/core/lib/transport/error_utils.c \
@@ -3561,6 +3573,7 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/lib/surface/server.c \
     src/core/lib/surface/validate_metadata.c \
     src/core/lib/surface/version.c \
+    src/core/lib/transport/bdp_estimator.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
     src/core/lib/transport/error_utils.c \
@@ -4152,6 +4165,7 @@ LIBGRPC++_CRONET_SRC = \
     src/core/lib/surface/server.c \
     src/core/lib/surface/validate_metadata.c \
     src/core/lib/surface/version.c \
+    src/core/lib/transport/bdp_estimator.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
     src/core/lib/transport/error_utils.c \
@@ -7967,6 +7981,38 @@ endif
 endif
 
 
+BDP_ESTIMATOR_TEST_SRC = \
+    test/core/transport/bdp_estimator_test.c \
+
+BDP_ESTIMATOR_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(BDP_ESTIMATOR_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/bdp_estimator_test: openssl_dep_error
+
+else
+
+
+
+$(BINDIR)/$(CONFIG)/bdp_estimator_test: $(BDP_ESTIMATOR_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) $(BDP_ESTIMATOR_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)/bdp_estimator_test
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/core/transport/bdp_estimator_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgpr.a
+
+deps_bdp_estimator_test: $(BDP_ESTIMATOR_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(BDP_ESTIMATOR_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 BIN_DECODER_TEST_SRC = \
     test/core/transport/chttp2/bin_decoder_test.c \
 
@@ -14727,6 +14773,49 @@ endif
 endif
 
 
+WRITES_PER_RPC_TEST_SRC = \
+    test/cpp/performance/writes_per_rpc_test.cc \
+
+WRITES_PER_RPC_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(WRITES_PER_RPC_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/writes_per_rpc_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)/$(CONFIG)/writes_per_rpc_test: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/writes_per_rpc_test: $(PROTOBUF_DEP) $(WRITES_PER_RPC_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) $(WRITES_PER_RPC_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)/writes_per_rpc_test
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/cpp/performance/writes_per_rpc_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_writes_per_rpc_test: $(WRITES_PER_RPC_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(WRITES_PER_RPC_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
 PUBLIC_HEADERS_MUST_BE_C89_SRC = \
     test/core/surface/public_headers_must_be_c89.c \
 
diff --git a/binding.gyp b/binding.gyp
index fe9c425bff..1815a5a476 100644
--- a/binding.gyp
+++ b/binding.gyp
@@ -707,6 +707,7 @@
         'src/core/lib/surface/server.c',
         'src/core/lib/surface/validate_metadata.c',
         'src/core/lib/surface/version.c',
+        'src/core/lib/transport/bdp_estimator.c',
         'src/core/lib/transport/byte_stream.c',
         'src/core/lib/transport/connectivity_state.c',
         'src/core/lib/transport/error_utils.c',
diff --git a/build.yaml b/build.yaml
index 3cec9c5bd2..456db28cef 100644
--- a/build.yaml
+++ b/build.yaml
@@ -256,6 +256,7 @@ filegroups:
   - src/core/lib/surface/lame_client.h
   - src/core/lib/surface/server.h
   - src/core/lib/surface/validate_metadata.h
+  - src/core/lib/transport/bdp_estimator.h
   - src/core/lib/transport/byte_stream.h
   - src/core/lib/transport/connectivity_state.h
   - src/core/lib/transport/error_utils.h
@@ -375,6 +376,7 @@ filegroups:
   - src/core/lib/surface/server.c
   - src/core/lib/surface/validate_metadata.c
   - src/core/lib/surface/version.c
+  - src/core/lib/transport/bdp_estimator.c
   - src/core/lib/transport/byte_stream.c
   - src/core/lib/transport/connectivity_state.c
   - src/core/lib/transport/error_utils.c
@@ -1442,6 +1444,16 @@ targets:
   - gpr
   exclude_iomgrs:
   - uv
+- name: bdp_estimator_test
+  build: test
+  language: c
+  src:
+  - test/core/transport/bdp_estimator_test.c
+  deps:
+  - grpc_test_util
+  - grpc
+  - gpr_test_util
+  - gpr
 - name: bin_decoder_test
   build: test
   language: c
@@ -2945,6 +2957,8 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+  args:
+  - --benchmark_min_time=0
   platforms:
   - mac
   - linux
@@ -3727,6 +3741,24 @@ targets:
   - grpc
   - gpr_test_util
   - gpr
+- name: writes_per_rpc_test
+  gtest: true
+  cpu_cost: 0.5
+  build: test
+  language: c++
+  src:
+  - test/cpp/performance/writes_per_rpc_test.cc
+  deps:
+  - grpc++_test_util
+  - grpc_test_util
+  - grpc++
+  - grpc
+  - gpr_test_util
+  - gpr
+  platforms:
+  - mac
+  - linux
+  - posix
 - name: public_headers_must_be_c89
   build: test
   language: c89
diff --git a/config.m4 b/config.m4
index 2a3ba5502d..2c6c89f3ee 100644
--- a/config.m4
+++ b/config.m4
@@ -186,6 +186,7 @@ if test "$PHP_GRPC" != "no"; then
     src/core/lib/surface/server.c \
     src/core/lib/surface/validate_metadata.c \
     src/core/lib/surface/version.c \
+    src/core/lib/transport/bdp_estimator.c \
     src/core/lib/transport/byte_stream.c \
     src/core/lib/transport/connectivity_state.c \
     src/core/lib/transport/error_utils.c \
diff --git a/doc/environment_variables.md b/doc/environment_variables.md
index 2c83972aa1..a380673233 100644
--- a/doc/environment_variables.md
+++ b/doc/environment_variables.md
@@ -35,6 +35,7 @@ some configuration as environment variables that can be set.
   A comma separated list of tracers that provide additional insight into how
   gRPC C core is processing requests via debug logs. Available tracers include:
   - api - traces api calls to the C core
+  - bdp_estimator - traces behavior of bdp estimation logic
   - call_error - traces the possible errors contributing to final call status
   - channel - traces operations on the C core channel stack
   - combiner - traces combiner lock state
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
index 39e0c340ea..87471ab9d0 100644
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@@ -342,6 +342,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/surface/lame_client.h',
                       'src/core/lib/surface/server.h',
                       'src/core/lib/surface/validate_metadata.h',
+                      'src/core/lib/transport/bdp_estimator.h',
                       'src/core/lib/transport/byte_stream.h',
                       'src/core/lib/transport/connectivity_state.h',
                       'src/core/lib/transport/error_utils.h',
@@ -544,6 +545,7 @@ Pod::Spec.new do |s|
                       'src/core/lib/surface/server.c',
                       'src/core/lib/surface/validate_metadata.c',
                       'src/core/lib/surface/version.c',
+                      'src/core/lib/transport/bdp_estimator.c',
                       'src/core/lib/transport/byte_stream.c',
                       'src/core/lib/transport/connectivity_state.c',
                       'src/core/lib/transport/error_utils.c',
@@ -765,6 +767,7 @@ Pod::Spec.new do |s|
                               'src/core/lib/surface/lame_client.h',
                               'src/core/lib/surface/server.h',
                               'src/core/lib/surface/validate_metadata.h',
+                              'src/core/lib/transport/bdp_estimator.h',
                               'src/core/lib/transport/byte_stream.h',
                               'src/core/lib/transport/connectivity_state.h',
                               'src/core/lib/transport/error_utils.h',
diff --git a/grpc.gemspec b/grpc.gemspec
index 874af6be41..7b132686c8 100755
--- a/grpc.gemspec
+++ b/grpc.gemspec
@@ -259,6 +259,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/surface/lame_client.h )
   s.files += %w( src/core/lib/surface/server.h )
   s.files += %w( src/core/lib/surface/validate_metadata.h )
+  s.files += %w( src/core/lib/transport/bdp_estimator.h )
   s.files += %w( src/core/lib/transport/byte_stream.h )
   s.files += %w( src/core/lib/transport/connectivity_state.h )
   s.files += %w( src/core/lib/transport/error_utils.h )
@@ -461,6 +462,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/surface/server.c )
   s.files += %w( src/core/lib/surface/validate_metadata.c )
   s.files += %w( src/core/lib/surface/version.c )
+  s.files += %w( src/core/lib/transport/bdp_estimator.c )
   s.files += %w( src/core/lib/transport/byte_stream.c )
   s.files += %w( src/core/lib/transport/connectivity_state.c )
   s.files += %w( src/core/lib/transport/error_utils.c )
diff --git a/include/grpc/impl/codegen/grpc_types.h b/include/grpc/impl/codegen/grpc_types.h
index 442c40069e..7fbaf56e75 100644
--- a/include/grpc/impl/codegen/grpc_types.h
+++ b/include/grpc/impl/codegen/grpc_types.h
@@ -179,6 +179,15 @@ typedef struct {
     Larger values give lower CPU usage for large messages, but more head of line
     blocking for small messages. */
 #define GRPC_ARG_HTTP2_MAX_FRAME_SIZE "grpc.http2.max_frame_size"
+/** Minimum time (in milliseconds) between successive ping frames being sent */
+#define GRPC_ARG_HTTP2_MIN_TIME_BETWEEN_PINGS_MS \
+  "grpc.http2.min_time_between_pings_ms"
+/** How many pings can we send before needing to send a data frame or header
+    frame?
+    (0 indicates that an infinite number of pings can be sent without sending
+     a data frame or header frame) */
+#define GRPC_ARG_HTTP2_MAX_PINGS_WITHOUT_DATA \
+  "grpc.http2.max_pings_without_data"
 /** How much data are we willing to queue up per stream if
     GRPC_WRITE_BUFFER_HINT is set? This is an upper bound */
 #define GRPC_ARG_HTTP2_WRITE_BUFFER_SIZE "grpc.http2.write_buffer_size"
diff --git a/package.xml b/package.xml
index 68536c3de2..e4c0e83cc7 100644
--- a/package.xml
+++ b/package.xml
@@ -268,6 +268,7 @@
     <file baseinstalldir="/" name="src/core/lib/surface/lame_client.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/server.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/validate_metadata.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/transport/bdp_estimator.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/byte_stream.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/connectivity_state.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/error_utils.h" role="src" />
@@ -470,6 +471,7 @@
     <file baseinstalldir="/" name="src/core/lib/surface/server.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/validate_metadata.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/surface/version.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/transport/bdp_estimator.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/byte_stream.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/connectivity_state.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/transport/error_utils.c" role="src" />
diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.c b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
index 15f486d676..fa18f5a725 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
@@ -124,6 +124,21 @@ static void close_transport_locked(grpc_exec_ctx *exec_ctx,
 static void end_all_the_calls(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                               grpc_error *error);
 
+static void start_bdp_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
+                                  grpc_error *error);
+static void finish_bdp_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
+                                   grpc_error *error);
+
+static void cancel_pings(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+                         grpc_error *error);
+static void send_ping_locked(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+                             grpc_chttp2_ping_type ping_type,
+                             grpc_closure *on_initiate,
+                             grpc_closure *on_complete);
+
+#define DEFAULT_MIN_TIME_BETWEEN_PINGS_MS 0
+#define DEFAULT_MAX_PINGS_BETWEEN_DATA 3
+
 /*******************************************************************************
  * CONSTRUCTION/DESTRUCTION/REFCOUNTING
  */
@@ -155,16 +170,7 @@ static void destruct_transport(grpc_exec_ctx *exec_ctx,
 
   grpc_combiner_destroy(exec_ctx, t->combiner);
 
-  /* callback remaining pings: they're not allowed to call into the transpot,
-     and maybe they hold resources that need to be freed */
-  while (t->pings.next != &t->pings) {
-    grpc_chttp2_outstanding_ping *ping = t->pings.next;
-    grpc_closure_sched(exec_ctx, ping->on_recv,
-                       GRPC_ERROR_CREATE("Transport closed"));
-    ping->next->prev = ping->prev;
-    ping->prev->next = ping->next;
-    gpr_free(ping);
-  }
+  cancel_pings(exec_ctx, t, GRPC_ERROR_CREATE("Transport destroyed"));
 
   while (t->write_cb_pool) {
     grpc_chttp2_write_cb *next = t->write_cb_pool->next;
@@ -172,6 +178,7 @@ static void destruct_transport(grpc_exec_ctx *exec_ctx,
     t->write_cb_pool = next;
   }
 
+  gpr_free(t->ping_acks);
   gpr_free(t->peer_string);
   gpr_free(t);
 }
@@ -224,10 +231,6 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   t->is_client = is_client;
   t->outgoing_window = DEFAULT_WINDOW;
   t->incoming_window = DEFAULT_WINDOW;
-  t->stream_lookahead = DEFAULT_WINDOW;
-  t->connection_window_target = DEFAULT_CONNECTION_WINDOW_TARGET;
-  t->ping_counter = 1;
-  t->pings.next = t->pings.prev = &t->pings;
   t->deframe_state = is_client ? GRPC_DTS_FH_0 : GRPC_DTS_CLIENT_PREFIX_0;
   t->is_first_frame = true;
   grpc_connectivity_state_init(
@@ -248,6 +251,22 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   grpc_closure_init(&t->destructive_reclaimer_locked,
                     destructive_reclaimer_locked, t,
                     grpc_combiner_scheduler(t->combiner, false));
+  grpc_closure_init(&t->start_bdp_ping_locked, start_bdp_ping_locked, t,
+                    grpc_combiner_scheduler(t->combiner, false));
+  grpc_closure_init(&t->finish_bdp_ping_locked, finish_bdp_ping_locked, t,
+                    grpc_combiner_scheduler(t->combiner, false));
+
+  grpc_bdp_estimator_init(&t->bdp_estimator, t->peer_string);
+  t->last_pid_update = gpr_now(GPR_CLOCK_MONOTONIC);
+  grpc_pid_controller_init(
+      &t->pid_controller,
+      (grpc_pid_controller_args){.gain_p = 4,
+                                 .gain_i = 8,
+                                 .gain_d = 0,
+                                 .initial_control_value = log2(DEFAULT_WINDOW),
+                                 .min_control_value = -1,
+                                 .max_control_value = 22,
+                                 .integral_range = 10});
 
   grpc_chttp2_goaway_parser_init(&t->goaway_parser);
   grpc_chttp2_hpack_parser_init(exec_ctx, &t->hpack_parser);
@@ -290,6 +309,12 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
                DEFAULT_MAX_HEADER_LIST_SIZE);
 
+  t->ping_policy = (grpc_chttp2_repeated_ping_policy){
+      .max_pings_without_data = DEFAULT_MAX_PINGS_BETWEEN_DATA,
+      .min_time_between_pings =
+          gpr_time_from_millis(DEFAULT_MIN_TIME_BETWEEN_PINGS_MS, GPR_TIMESPAN),
+  };
+
   if (channel_args) {
     for (i = 0; i < channel_args->num_args; i++) {
       if (0 == strcmp(channel_args->args[i].key,
@@ -307,14 +332,6 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
           }
         }
       } else if (0 == strcmp(channel_args->args[i].key,
-                             GRPC_ARG_HTTP2_STREAM_LOOKAHEAD_BYTES)) {
-        const grpc_integer_options options = {-1, 5, INT_MAX};
-        const int value =
-            grpc_channel_arg_get_integer(&channel_args->args[i], options);
-        if (value >= 0) {
-          t->stream_lookahead = (uint32_t)value;
-        }
-      } else if (0 == strcmp(channel_args->args[i].key,
                              GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_ENCODER)) {
         const grpc_integer_options options = {-1, 0, INT_MAX};
         const int value =
@@ -324,6 +341,19 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                                                            (uint32_t)value);
         }
       } else if (0 == strcmp(channel_args->args[i].key,
+                             GRPC_ARG_HTTP2_MAX_PINGS_WITHOUT_DATA)) {
+        t->ping_policy.max_pings_without_data = grpc_channel_arg_get_integer(
+            &channel_args->args[i],
+            (grpc_integer_options){DEFAULT_MAX_PINGS_BETWEEN_DATA, 0, INT_MAX});
+      } else if (0 == strcmp(channel_args->args[i].key,
+                             GRPC_ARG_HTTP2_MIN_TIME_BETWEEN_PINGS_MS)) {
+        t->ping_policy.min_time_between_pings = gpr_time_from_millis(
+            grpc_channel_arg_get_integer(
+                &channel_args->args[i],
+                (grpc_integer_options){DEFAULT_MIN_TIME_BETWEEN_PINGS_MS, 0,
+                                       INT_MAX}),
+            GPR_TIMESPAN);
+      } else if (0 == strcmp(channel_args->args[i].key,
                              GRPC_ARG_HTTP2_WRITE_BUFFER_SIZE)) {
         t->write_buffer_size = (uint32_t)grpc_channel_arg_get_integer(
             &channel_args->args[i],
@@ -334,24 +364,26 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
           grpc_chttp2_setting_id setting_id;
           grpc_integer_options integer_options;
           bool availability[2] /* server, client */;
-        } settings_map[] = {
-            {GRPC_ARG_MAX_CONCURRENT_STREAMS,
-             GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS,
-             {-1, 0, INT_MAX},
-             {true, false}},
-            {GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_DECODER,
-             GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE,
-             {-1, 0, INT_MAX},
-             {true, true}},
-            {GRPC_ARG_MAX_METADATA_SIZE,
-             GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
-             {-1, 0, INT_MAX},
-             {true, true}},
-            {GRPC_ARG_HTTP2_MAX_FRAME_SIZE,
-             GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE,
-             {-1, 16384, 16777215},
-             {true, true}},
-        };
+        } settings_map[] = {{GRPC_ARG_MAX_CONCURRENT_STREAMS,
+                             GRPC_CHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS,
+                             {-1, 0, INT32_MAX},
+                             {true, false}},
+                            {GRPC_ARG_HTTP2_HPACK_TABLE_SIZE_DECODER,
+                             GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE,
+                             {-1, 0, INT32_MAX},
+                             {true, true}},
+                            {GRPC_ARG_MAX_METADATA_SIZE,
+                             GRPC_CHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE,
+                             {-1, 0, INT32_MAX},
+                             {true, true}},
+                            {GRPC_ARG_HTTP2_MAX_FRAME_SIZE,
+                             GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE,
+                             {-1, 16384, 16777215},
+                             {true, true}},
+                            {GRPC_ARG_HTTP2_STREAM_LOOKAHEAD_BYTES,
+                             GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE,
+                             {-1, 5, INT32_MAX},
+                             {true, true}}};
         for (j = 0; j < (int)GPR_ARRAY_SIZE(settings_map); j++) {
           if (0 == strcmp(channel_args->args[i].key,
                           settings_map[j].channel_arg_name)) {
@@ -374,6 +406,9 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     }
   }
 
+  t->ping_state.pings_before_data_required =
+      t->ping_policy.max_pings_without_data;
+
   grpc_chttp2_initiate_write(exec_ctx, t, false, "init");
   post_benign_reclaimer(exec_ctx, t);
 }
@@ -425,6 +460,7 @@ static void close_transport_locked(grpc_exec_ctx *exec_ctx,
       GRPC_CHTTP2_STREAM_UNREF(exec_ctx, s, "chttp2_writing:close");
     }
     end_all_the_calls(exec_ctx, t, GRPC_ERROR_REF(error));
+    cancel_pings(exec_ctx, t, GRPC_ERROR_REF(error));
   }
   GRPC_ERROR_UNREF(error);
 }
@@ -475,11 +511,6 @@ static int init_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
 
   if (server_data) {
     s->id = (uint32_t)(uintptr_t)server_data;
-    s->outgoing_window = t->settings[GRPC_PEER_SETTINGS]
-                                    [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
-    s->incoming_window = s->max_recv_bytes =
-        t->settings[GRPC_SENT_SETTINGS]
-                   [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
     *t->accepting_stream = s;
     grpc_chttp2_stream_map_add(&t->stream_map, s->id, s);
     post_destructive_reclaimer(exec_ctx, t);
@@ -508,6 +539,7 @@ static void destroy_stream_locked(grpc_exec_ctx *exec_ctx, void *sp,
   }
 
   grpc_chttp2_list_remove_stalled_by_transport(t, s);
+  grpc_chttp2_list_remove_stalled_by_stream(t, s);
 
   for (int i = 0; i < STREAM_LIST_COUNT; i++) {
     if (s->included[i]) {
@@ -647,13 +679,21 @@ void grpc_chttp2_initiate_write(grpc_exec_ctx *exec_ctx,
   GPR_TIMER_END("grpc_chttp2_initiate_write", 0);
 }
 
-void grpc_chttp2_become_writable(grpc_exec_ctx *exec_ctx,
-                                 grpc_chttp2_transport *t,
-                                 grpc_chttp2_stream *s, bool covered_by_poller,
-                                 const char *reason) {
+void grpc_chttp2_become_writable(
+    grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t, grpc_chttp2_stream *s,
+    grpc_chttp2_stream_write_type stream_write_type, const char *reason) {
   if (!t->closed && grpc_chttp2_list_add_writable_stream(t, s)) {
     GRPC_CHTTP2_STREAM_REF(s, "chttp2_writing:become");
-    grpc_chttp2_initiate_write(exec_ctx, t, covered_by_poller, reason);
+  }
+  switch (stream_write_type) {
+    case GRPC_CHTTP2_STREAM_WRITE_PIGGYBACK:
+      break;
+    case GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED:
+      grpc_chttp2_initiate_write(exec_ctx, t, true, reason);
+      break;
+    case GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED:
+      grpc_chttp2_initiate_write(exec_ctx, t, false, reason);
+      break;
   }
 }
 
@@ -781,7 +821,6 @@ void grpc_chttp2_add_incoming_goaway(grpc_exec_ctx *exec_ctx,
 static void maybe_start_some_streams(grpc_exec_ctx *exec_ctx,
                                      grpc_chttp2_transport *t) {
   grpc_chttp2_stream *s;
-  uint32_t stream_incoming_window;
   /* start streams where we have free grpc_chttp2_stream ids and free
    * concurrency */
   while (t->next_stream_id <= MAX_CLIENT_STREAM_ID &&
@@ -804,15 +843,11 @@ static void maybe_start_some_streams(grpc_exec_ctx *exec_ctx,
                              "no_more_stream_ids");
     }
 
-    s->outgoing_window = t->settings[GRPC_PEER_SETTINGS]
-                                    [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
-    s->incoming_window = stream_incoming_window =
-        t->settings[GRPC_SENT_SETTINGS]
-                   [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
-    s->max_recv_bytes = GPR_MAX(stream_incoming_window, s->max_recv_bytes);
     grpc_chttp2_stream_map_add(&t->stream_map, s->id, s);
     post_destructive_reclaimer(exec_ctx, t);
-    grpc_chttp2_become_writable(exec_ctx, t, s, true, "new_stream");
+    grpc_chttp2_become_writable(exec_ctx, t, s,
+                                GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
+                                "new_stream");
   }
   /* cancel out streams that will never be started */
   while (t->next_stream_id >= MAX_CLIENT_STREAM_ID &&
@@ -907,7 +942,9 @@ static void maybe_become_writable_due_to_send_msg(grpc_exec_ctx *exec_ctx,
                                                   grpc_chttp2_stream *s) {
   if (s->id != 0 && (!s->write_buffering ||
                      s->flow_controlled_buffer.length > t->write_buffer_size)) {
-    grpc_chttp2_become_writable(exec_ctx, t, s, true, "op.send_message");
+    grpc_chttp2_become_writable(exec_ctx, t, s,
+                                GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
+                                "op.send_message");
   }
 }
 
@@ -1069,7 +1106,8 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
           }
         } else {
           GPR_ASSERT(s->id != 0);
-          grpc_chttp2_become_writable(exec_ctx, t, s, true,
+          grpc_chttp2_become_writable(exec_ctx, t, s,
+                                      GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
                                       "op.send_initial_metadata");
         }
       } else {
@@ -1160,7 +1198,8 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
       } else if (s->id != 0) {
         /* TODO(ctiller): check if there's flow control for any outstanding
            bytes before going writable */
-        grpc_chttp2_become_writable(exec_ctx, t, s, true,
+        grpc_chttp2_become_writable(exec_ctx, t, s,
+                                    GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
                                     "op.send_trailing_metadata");
       }
     }
@@ -1179,8 +1218,7 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
     s->recv_message = op->recv_message;
     if (s->id != 0 &&
         (s->incoming_frames.head == NULL || s->incoming_frames.head->is_tail)) {
-      incoming_byte_stream_update_flow_control(exec_ctx, t, s,
-                                               t->stream_lookahead, 0);
+      incoming_byte_stream_update_flow_control(exec_ctx, t, s, 5, 0);
     }
     grpc_chttp2_maybe_complete_recv_message(exec_ctx, t, s);
   }
@@ -1224,43 +1262,46 @@ static void perform_stream_op(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   GPR_TIMER_END("perform_stream_op", 0);
 }
 
+static void cancel_pings(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+                         grpc_error *error) {
+  /* callback remaining pings: they're not allowed to call into the transpot,
+     and maybe they hold resources that need to be freed */
+  for (size_t i = 0; i < GRPC_CHTTP2_PING_TYPE_COUNT; i++) {
+    grpc_chttp2_ping_queue *pq = &t->ping_queues[i];
+    for (size_t j = 0; j < GRPC_CHTTP2_PCL_COUNT; j++) {
+      grpc_closure_list_fail_all(&pq->lists[j], GRPC_ERROR_REF(error));
+      grpc_closure_list_sched(exec_ctx, &pq->lists[j]);
+    }
+  }
+  GRPC_ERROR_UNREF(error);
+}
+
 static void send_ping_locked(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                             grpc_closure *on_recv) {
-  grpc_chttp2_outstanding_ping *p = gpr_malloc(sizeof(*p));
-  p->next = &t->pings;
-  p->prev = p->next->prev;
-  p->prev->next = p->next->prev = p;
-  p->id[0] = (uint8_t)((t->ping_counter >> 56) & 0xff);
-  p->id[1] = (uint8_t)((t->ping_counter >> 48) & 0xff);
-  p->id[2] = (uint8_t)((t->ping_counter >> 40) & 0xff);
-  p->id[3] = (uint8_t)((t->ping_counter >> 32) & 0xff);
-  p->id[4] = (uint8_t)((t->ping_counter >> 24) & 0xff);
-  p->id[5] = (uint8_t)((t->ping_counter >> 16) & 0xff);
-  p->id[6] = (uint8_t)((t->ping_counter >> 8) & 0xff);
-  p->id[7] = (uint8_t)(t->ping_counter & 0xff);
-  t->ping_counter++;
-  p->on_recv = on_recv;
-  grpc_slice_buffer_add(&t->qbuf, grpc_chttp2_ping_create(0, p->id));
-  grpc_chttp2_initiate_write(exec_ctx, t, true, "send_ping");
+                             grpc_chttp2_ping_type ping_type,
+                             grpc_closure *on_initiate, grpc_closure *on_ack) {
+  grpc_chttp2_ping_queue *pq = &t->ping_queues[ping_type];
+  grpc_closure_list_append(&pq->lists[GRPC_CHTTP2_PCL_INITIATE], on_initiate,
+                           GRPC_ERROR_NONE);
+  if (grpc_closure_list_append(&pq->lists[GRPC_CHTTP2_PCL_NEXT], on_ack,
+                               GRPC_ERROR_NONE)) {
+    grpc_chttp2_initiate_write(exec_ctx, t, false, "send_ping");
+  }
 }
 
 void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                          const uint8_t *opaque_8bytes) {
-  grpc_chttp2_outstanding_ping *ping;
-  for (ping = t->pings.next; ping != &t->pings; ping = ping->next) {
-    if (0 == memcmp(opaque_8bytes, ping->id, 8)) {
-      grpc_closure_sched(exec_ctx, ping->on_recv, GRPC_ERROR_NONE);
-      ping->next->prev = ping->prev;
-      ping->prev->next = ping->next;
-      gpr_free(ping);
-      return;
-    }
+                          uint64_t id) {
+  grpc_chttp2_ping_queue *pq =
+      &t->ping_queues[id % GRPC_CHTTP2_PING_TYPE_COUNT];
+  if (pq->inflight_id != id) {
+    char *from = grpc_endpoint_get_peer(t->ep);
+    gpr_log(GPR_DEBUG, "Unknown ping response from %s: %" PRIx64, from, id);
+    gpr_free(from);
+    return;
+  }
+  grpc_closure_list_sched(exec_ctx, &pq->lists[GRPC_CHTTP2_PCL_INFLIGHT]);
+  if (!grpc_closure_list_empty(pq->lists[GRPC_CHTTP2_PCL_NEXT])) {
+    grpc_chttp2_initiate_write(exec_ctx, t, false, "continue_pings");
   }
-  char *msg = gpr_dump((const char *)opaque_8bytes, 8, GPR_DUMP_HEX);
-  char *from = grpc_endpoint_get_peer(t->ep);
-  gpr_log(GPR_DEBUG, "Unknown ping response from %s: %s", from, msg);
-  gpr_free(from);
-  gpr_free(msg);
 }
 
 static void send_goaway(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
@@ -1308,7 +1349,8 @@ static void perform_transport_op_locked(grpc_exec_ctx *exec_ctx,
   }
 
   if (op->send_ping) {
-    send_ping_locked(exec_ctx, t, op->send_ping);
+    send_ping_locked(exec_ctx, t, GRPC_CHTTP2_PING_ON_NEXT_WRITE, NULL,
+                     op->send_ping);
   }
 
   if (close_transport != GRPC_ERROR_NONE) {
@@ -1733,34 +1775,28 @@ static void end_all_the_calls(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   GRPC_ERROR_UNREF(error);
 }
 
-/** update window from a settings change */
-typedef struct {
-  grpc_chttp2_transport *t;
-  grpc_exec_ctx *exec_ctx;
-} update_global_window_args;
+/*******************************************************************************
+ * INPUT PROCESSING - PARSING
+ */
 
-static void update_global_window(void *args, uint32_t id, void *stream) {
-  update_global_window_args *a = args;
-  grpc_chttp2_transport *t = a->t;
-  grpc_chttp2_stream *s = stream;
-  int was_zero;
-  int is_zero;
-  int64_t initial_window_update = t->initial_window_update;
-
-  if (initial_window_update > 0) {
-    was_zero = s->outgoing_window <= 0;
-    GRPC_CHTTP2_FLOW_CREDIT_STREAM("settings", t, s, outgoing_window,
-                                   initial_window_update);
-    is_zero = s->outgoing_window <= 0;
-
-    if (was_zero && !is_zero) {
-      grpc_chttp2_become_writable(a->exec_ctx, t, s, true,
-                                  "update_global_window");
-    }
+static void update_bdp(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
+                       double bdp_dbl) {
+  uint32_t bdp;
+  if (bdp_dbl <= 0) {
+    bdp = 0;
+  } else if (bdp_dbl > UINT32_MAX) {
+    bdp = UINT32_MAX;
   } else {
-    GRPC_CHTTP2_FLOW_DEBIT_STREAM("settings", t, s, outgoing_window,
-                                  -initial_window_update);
+    bdp = (uint32_t)(bdp_dbl);
+  }
+  int64_t delta =
+      (int64_t)bdp -
+      (int64_t)t->settings[GRPC_LOCAL_SETTINGS]
+                          [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
+  if (delta == 0 || (bdp != 0 && delta > -1024 && delta < 1024)) {
+    return;
   }
+  push_setting(exec_ctx, t, GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE, bdp);
 }
 
 /*******************************************************************************
@@ -1802,6 +1838,7 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
   GPR_TIMER_BEGIN("reading_action_locked", 0);
 
   grpc_chttp2_transport *t = tp;
+  bool need_bdp_ping = false;
 
   GRPC_ERROR_REF(error);
 
@@ -1819,9 +1856,14 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
     grpc_error *errors[3] = {GRPC_ERROR_REF(error), GRPC_ERROR_NONE,
                              GRPC_ERROR_NONE};
     for (; i < t->read_buffer.count && errors[1] == GRPC_ERROR_NONE; i++) {
+      if (grpc_bdp_estimator_add_incoming_bytes(
+              &t->bdp_estimator,
+              (int64_t)GRPC_SLICE_LENGTH(t->read_buffer.slices[i]))) {
+        need_bdp_ping = true;
+      }
       errors[1] =
           grpc_chttp2_perform_read(exec_ctx, t, t->read_buffer.slices[i]);
-    };
+    }
     if (errors[1] != GRPC_ERROR_NONE) {
       errors[2] = try_http_parsing(exec_ctx, t);
       GRPC_ERROR_UNREF(error);
@@ -1835,21 +1877,16 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
 
     GPR_TIMER_BEGIN("post_parse_locked", 0);
     if (t->initial_window_update != 0) {
-      update_global_window_args args = {t, exec_ctx};
-      grpc_chttp2_stream_map_for_each(&t->stream_map, update_global_window,
-                                      &args);
+      if (t->initial_window_update > 0) {
+        grpc_chttp2_stream *s;
+        while (grpc_chttp2_list_pop_stalled_by_stream(t, &s)) {
+          grpc_chttp2_become_writable(
+              exec_ctx, t, s, GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED,
+              "unstalled");
+        }
+      }
       t->initial_window_update = 0;
     }
-    /* handle higher level things */
-    if (t->incoming_window < t->connection_window_target * 3 / 4) {
-      int64_t announce_bytes = t->connection_window_target - t->incoming_window;
-      GRPC_CHTTP2_FLOW_CREDIT_TRANSPORT("parsed", t, announce_incoming_window,
-                                        announce_bytes);
-      GRPC_CHTTP2_FLOW_CREDIT_TRANSPORT("parsed", t, incoming_window,
-                                        announce_bytes);
-      grpc_chttp2_initiate_write(exec_ctx, t, false, "global incoming window");
-    }
-
     GPR_TIMER_END("post_parse_locked", 0);
   }
 
@@ -1870,6 +1907,35 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
   if (keep_reading) {
     grpc_endpoint_read(exec_ctx, t->ep, &t->read_buffer,
                        &t->read_action_locked);
+
+    if (need_bdp_ping) {
+      GRPC_CHTTP2_REF_TRANSPORT(t, "bdp_ping");
+      grpc_bdp_estimator_schedule_ping(&t->bdp_estimator);
+      send_ping_locked(exec_ctx, t,
+                       GRPC_CHTTP2_PING_BEFORE_TRANSPORT_WINDOW_UPDATE,
+                       &t->start_bdp_ping_locked, &t->finish_bdp_ping_locked);
+    }
+
+    int64_t estimate = -1;
+    if (grpc_bdp_estimator_get_estimate(&t->bdp_estimator, &estimate)) {
+      double target = 1 + log2((double)estimate);
+      double memory_pressure = grpc_resource_quota_get_memory_pressure(
+          grpc_resource_user_quota(grpc_endpoint_get_resource_user(t->ep)));
+      if (memory_pressure > 0.8) {
+        target *= 1 - GPR_MIN(1, (memory_pressure - 0.8) / 0.1);
+      }
+      double bdp_error = target - grpc_pid_controller_last(&t->pid_controller);
+      gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+      gpr_timespec dt_timespec = gpr_time_sub(now, t->last_pid_update);
+      double dt = (double)dt_timespec.tv_sec + dt_timespec.tv_nsec * 1e-9;
+      if (dt > 0.1) {
+        dt = 0.1;
+      }
+      double log2_bdp_guess =
+          grpc_pid_controller_update(&t->pid_controller, bdp_error, dt);
+      update_bdp(exec_ctx, t, pow(2, log2_bdp_guess));
+      t->last_pid_update = now;
+    }
     GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "keep_reading");
   } else {
     GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "reading_action");
@@ -1882,6 +1948,26 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
   GPR_TIMER_END("reading_action_locked", 0);
 }
 
+static void start_bdp_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
+                                  grpc_error *error) {
+  grpc_chttp2_transport *t = tp;
+  if (grpc_http_trace) {
+    gpr_log(GPR_DEBUG, "%s: Start BDP ping", t->peer_string);
+  }
+  grpc_bdp_estimator_start_ping(&t->bdp_estimator);
+}
+
+static void finish_bdp_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
+                                   grpc_error *error) {
+  grpc_chttp2_transport *t = tp;
+  if (grpc_http_trace) {
+    gpr_log(GPR_DEBUG, "%s: Complete BDP ping", t->peer_string);
+  }
+  grpc_bdp_estimator_complete_ping(&t->bdp_estimator);
+
+  GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "bdp_ping");
+}
+
 /*******************************************************************************
  * CALLBACK LOOP
  */
@@ -1932,10 +2018,12 @@ static void incoming_byte_stream_update_flow_control(grpc_exec_ctx *exec_ctx,
                                                      size_t max_size_hint,
                                                      size_t have_already) {
   uint32_t max_recv_bytes;
+  uint32_t initial_window_size =
+      t->settings[GRPC_SENT_SETTINGS][GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE];
 
   /* clamp max recv hint to an allowable size */
-  if (max_size_hint >= UINT32_MAX - t->stream_lookahead) {
-    max_recv_bytes = UINT32_MAX - t->stream_lookahead;
+  if (max_size_hint >= UINT32_MAX - initial_window_size) {
+    max_recv_bytes = UINT32_MAX - initial_window_size;
   } else {
     max_recv_bytes = (uint32_t)max_size_hint;
   }
@@ -1948,20 +2036,26 @@ static void incoming_byte_stream_update_flow_control(grpc_exec_ctx *exec_ctx,
   }
 
   /* add some small lookahead to keep pipelines flowing */
-  GPR_ASSERT(max_recv_bytes <= UINT32_MAX - t->stream_lookahead);
-  max_recv_bytes += t->stream_lookahead;
-  if (s->max_recv_bytes < max_recv_bytes) {
-    uint32_t add_max_recv_bytes = max_recv_bytes - s->max_recv_bytes;
-    bool new_window_write_is_covered_by_poller =
-        s->max_recv_bytes < have_already;
-    GRPC_CHTTP2_FLOW_CREDIT_STREAM("op", t, s, max_recv_bytes,
-                                   add_max_recv_bytes);
-    GRPC_CHTTP2_FLOW_CREDIT_STREAM("op", t, s, incoming_window,
+  GPR_ASSERT(max_recv_bytes <= UINT32_MAX - initial_window_size);
+  if (s->incoming_window_delta < max_recv_bytes && !s->read_closed) {
+    uint32_t add_max_recv_bytes =
+        (uint32_t)(max_recv_bytes - s->incoming_window_delta);
+    grpc_chttp2_stream_write_type write_type =
+        GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED;
+    if (s->incoming_window_delta + initial_window_size <
+        (int64_t)have_already) {
+      write_type = GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED;
+    }
+    GRPC_CHTTP2_FLOW_CREDIT_STREAM("op", t, s, incoming_window_delta,
                                    add_max_recv_bytes);
     GRPC_CHTTP2_FLOW_CREDIT_STREAM("op", t, s, announce_window,
                                    add_max_recv_bytes);
-    grpc_chttp2_become_writable(exec_ctx, t, s,
-                                new_window_write_is_covered_by_poller,
+    if ((int64_t)s->incoming_window_delta + (int64_t)initial_window_size -
+            (int64_t)s->announce_window >
+        (int64_t)initial_window_size / 2) {
+      write_type = GRPC_CHTTP2_STREAM_WRITE_PIGGYBACK;
+    }
+    grpc_chttp2_become_writable(exec_ctx, t, s, write_type,
                                 "read_incoming_stream");
   }
 }
diff --git a/src/core/ext/transport/chttp2/transport/frame_ping.c b/src/core/ext/transport/chttp2/transport/frame_ping.c
index 7de5f6362d..f487533c41 100644
--- a/src/core/ext/transport/chttp2/transport/frame_ping.c
+++ b/src/core/ext/transport/chttp2/transport/frame_ping.c
@@ -40,7 +40,7 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
-grpc_slice grpc_chttp2_ping_create(uint8_t ack, uint8_t *opaque_8bytes) {
+grpc_slice grpc_chttp2_ping_create(uint8_t ack, uint64_t opaque_8bytes) {
   grpc_slice slice = grpc_slice_malloc(9 + 8);
   uint8_t *p = GRPC_SLICE_START_PTR(slice);
 
@@ -53,7 +53,14 @@ grpc_slice grpc_chttp2_ping_create(uint8_t ack, uint8_t *opaque_8bytes) {
   *p++ = 0;
   *p++ = 0;
   *p++ = 0;
-  memcpy(p, opaque_8bytes, 8);
+  *p++ = (uint8_t)(opaque_8bytes >> 56);
+  *p++ = (uint8_t)(opaque_8bytes >> 48);
+  *p++ = (uint8_t)(opaque_8bytes >> 40);
+  *p++ = (uint8_t)(opaque_8bytes >> 32);
+  *p++ = (uint8_t)(opaque_8bytes >> 24);
+  *p++ = (uint8_t)(opaque_8bytes >> 16);
+  *p++ = (uint8_t)(opaque_8bytes >> 8);
+  *p++ = (uint8_t)(opaque_8bytes);
 
   return slice;
 }
@@ -70,6 +77,7 @@ grpc_error *grpc_chttp2_ping_parser_begin_frame(grpc_chttp2_ping_parser *parser,
   }
   parser->byte = 0;
   parser->is_ack = flags;
+  parser->opaque_8bytes = 0;
   return GRPC_ERROR_NONE;
 }
 
@@ -83,7 +91,7 @@ grpc_error *grpc_chttp2_ping_parser_parse(grpc_exec_ctx *exec_ctx, void *parser,
   grpc_chttp2_ping_parser *p = parser;
 
   while (p->byte != 8 && cur != end) {
-    p->opaque_8bytes[p->byte] = *cur;
+    p->opaque_8bytes |= (((uint64_t)*cur) << (8 * p->byte));
     cur++;
     p->byte++;
   }
@@ -93,8 +101,12 @@ grpc_error *grpc_chttp2_ping_parser_parse(grpc_exec_ctx *exec_ctx, void *parser,
     if (p->is_ack) {
       grpc_chttp2_ack_ping(exec_ctx, t, p->opaque_8bytes);
     } else {
-      grpc_slice_buffer_add(&t->qbuf,
-                            grpc_chttp2_ping_create(1, p->opaque_8bytes));
+      if (t->ping_ack_count == t->ping_ack_capacity) {
+        t->ping_ack_capacity = GPR_MAX(t->ping_ack_capacity * 3 / 2, 3);
+        t->ping_acks = gpr_realloc(
+            t->ping_acks, t->ping_ack_capacity * sizeof(*t->ping_acks));
+      }
+      t->ping_acks[t->ping_ack_count++] = p->opaque_8bytes;
       grpc_chttp2_initiate_write(exec_ctx, t, false, "ping response");
     }
   }
diff --git a/src/core/ext/transport/chttp2/transport/frame_ping.h b/src/core/ext/transport/chttp2/transport/frame_ping.h
index b9889e2d11..ef642465d7 100644
--- a/src/core/ext/transport/chttp2/transport/frame_ping.h
+++ b/src/core/ext/transport/chttp2/transport/frame_ping.h
@@ -41,10 +41,10 @@
 typedef struct {
   uint8_t byte;
   uint8_t is_ack;
-  uint8_t opaque_8bytes[8];
+  uint64_t opaque_8bytes;
 } grpc_chttp2_ping_parser;
 
-grpc_slice grpc_chttp2_ping_create(uint8_t ack, uint8_t *opaque_8bytes);
+grpc_slice grpc_chttp2_ping_create(uint8_t ack, uint64_t opaque_8bytes);
 
 grpc_error *grpc_chttp2_ping_parser_begin_frame(grpc_chttp2_ping_parser *parser,
                                                 uint32_t length, uint8_t flags);
diff --git a/src/core/ext/transport/chttp2/transport/frame_settings.c b/src/core/ext/transport/chttp2/transport/frame_settings.c
index be9b663ac1..82290e34cd 100644
--- a/src/core/ext/transport/chttp2/transport/frame_settings.c
+++ b/src/core/ext/transport/chttp2/transport/frame_settings.c
@@ -236,7 +236,7 @@ grpc_error *grpc_chttp2_settings_parser_parse(grpc_exec_ctx *exec_ctx, void *p,
           }
           if (parser->id == GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE &&
               parser->incoming_settings[parser->id] != parser->value) {
-            t->initial_window_update =
+            t->initial_window_update +=
                 (int64_t)parser->value - parser->incoming_settings[parser->id];
             if (grpc_http_trace) {
               gpr_log(GPR_DEBUG, "adding %d for initial_window change",
@@ -245,8 +245,9 @@ grpc_error *grpc_chttp2_settings_parser_parse(grpc_exec_ctx *exec_ctx, void *p,
           }
           parser->incoming_settings[parser->id] = parser->value;
           if (grpc_http_trace) {
-            gpr_log(GPR_DEBUG, "CHTTP2:%s: got setting %d = %d",
-                    t->is_client ? "CLI" : "SVR", parser->id, parser->value);
+            gpr_log(GPR_DEBUG, "CHTTP2:%s:%s: got setting %d = %d",
+                    t->is_client ? "CLI" : "SVR", t->peer_string, parser->id,
+                    parser->value);
           }
         } else if (grpc_http_trace) {
           gpr_log(GPR_ERROR, "CHTTP2: Ignoring unknown setting %d (value %d)",
diff --git a/src/core/ext/transport/chttp2/transport/frame_window_update.c b/src/core/ext/transport/chttp2/transport/frame_window_update.c
index 31a31c2871..8fa0bb471a 100644
--- a/src/core/ext/transport/chttp2/transport/frame_window_update.c
+++ b/src/core/ext/transport/chttp2/transport/frame_window_update.c
@@ -110,13 +110,12 @@ grpc_error *grpc_chttp2_window_update_parser_parse(
 
     if (t->incoming_stream_id != 0) {
       if (s != NULL) {
-        bool was_zero = s->outgoing_window <= 0;
-        GRPC_CHTTP2_FLOW_CREDIT_STREAM("parse", t, s, outgoing_window,
+        GRPC_CHTTP2_FLOW_CREDIT_STREAM("parse", t, s, outgoing_window_delta,
                                        received_update);
-        bool is_zero = s->outgoing_window <= 0;
-        if (was_zero && !is_zero) {
-          grpc_chttp2_become_writable(exec_ctx, t, s, false,
-                                      "stream.read_flow_control");
+        if (grpc_chttp2_list_remove_stalled_by_stream(t, s)) {
+          grpc_chttp2_become_writable(
+              exec_ctx, t, s, GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED,
+              "stream.read_flow_control");
         }
       }
     } else {
diff --git a/src/core/ext/transport/chttp2/transport/internal.h b/src/core/ext/transport/chttp2/transport/internal.h
index ee5edc92df..1dabf9edba 100644
--- a/src/core/ext/transport/chttp2/transport/internal.h
+++ b/src/core/ext/transport/chttp2/transport/internal.h
@@ -50,7 +50,9 @@
 #include "src/core/ext/transport/chttp2/transport/stream_map.h"
 #include "src/core/lib/iomgr/combiner.h"
 #include "src/core/lib/iomgr/endpoint.h"
+#include "src/core/lib/transport/bdp_estimator.h"
 #include "src/core/lib/transport/connectivity_state.h"
+#include "src/core/lib/transport/pid_controller.h"
 #include "src/core/lib/transport/transport_impl.h"
 
 /* streams are kept in various linked lists depending on what things need to
@@ -59,6 +61,7 @@ typedef enum {
   GRPC_CHTTP2_LIST_WRITABLE,
   GRPC_CHTTP2_LIST_WRITING,
   GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT,
+  GRPC_CHTTP2_LIST_STALLED_BY_STREAM,
   /** streams that are waiting to start because there are too many concurrent
       streams on the connection */
   GRPC_CHTTP2_LIST_WAITING_FOR_CONCURRENCY,
@@ -72,6 +75,34 @@ typedef enum {
   GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE_AND_COVERED_BY_POLLER,
 } grpc_chttp2_write_state;
 
+typedef enum {
+  GRPC_CHTTP2_PING_ON_NEXT_WRITE = 0,
+  GRPC_CHTTP2_PING_BEFORE_TRANSPORT_WINDOW_UPDATE,
+  GRPC_CHTTP2_PING_TYPE_COUNT /* must be last */
+} grpc_chttp2_ping_type;
+
+typedef enum {
+  GRPC_CHTTP2_PCL_INITIATE = 0,
+  GRPC_CHTTP2_PCL_NEXT,
+  GRPC_CHTTP2_PCL_INFLIGHT,
+  GRPC_CHTTP2_PCL_COUNT /* must be last */
+} grpc_chttp2_ping_closure_list;
+
+typedef struct {
+  grpc_closure_list lists[GRPC_CHTTP2_PCL_COUNT];
+  uint64_t inflight_id;
+} grpc_chttp2_ping_queue;
+
+typedef struct {
+  gpr_timespec min_time_between_pings;
+  int max_pings_without_data;
+} grpc_chttp2_repeated_ping_policy;
+
+typedef struct {
+  gpr_timespec last_ping_sent_time;
+  int pings_before_data_required;
+} grpc_chttp2_repeated_ping_state;
+
 /* deframer state for the overall http2 stream of bytes */
 typedef enum {
   /* prefix: one entry per http2 connection prefix byte */
@@ -144,14 +175,6 @@ typedef enum {
   GRPC_CHTTP2_GOAWAY_SENT,
 } grpc_chttp2_sent_goaway_state;
 
-/* Outstanding ping request data */
-typedef struct grpc_chttp2_outstanding_ping {
-  uint8_t id[8];
-  grpc_closure *on_recv;
-  struct grpc_chttp2_outstanding_ping *next;
-  struct grpc_chttp2_outstanding_ping *prev;
-} grpc_chttp2_outstanding_ping;
-
 typedef struct grpc_chttp2_write_cb {
   int64_t call_at_byte;
   grpc_closure *closure;
@@ -271,16 +294,19 @@ struct grpc_chttp2_transport {
       copied to next_stream_id in parsing when parsing commences */
   uint32_t next_stream_id;
 
-  /** how far to lookahead in a stream? */
-  uint32_t stream_lookahead;
-
   /** last new stream id */
   uint32_t last_new_stream_id;
 
-  /** pings awaiting responses */
-  grpc_chttp2_outstanding_ping pings;
-  /** next payload for an outgoing ping */
-  uint64_t ping_counter;
+  /** ping queues for various ping insertion points */
+  grpc_chttp2_ping_queue ping_queues[GRPC_CHTTP2_PING_TYPE_COUNT];
+  grpc_chttp2_repeated_ping_policy ping_policy;
+  grpc_chttp2_repeated_ping_state ping_state;
+  uint64_t ping_ctr; /* unique id for pings */
+
+  /** ping acks */
+  size_t ping_ack_count;
+  size_t ping_ack_capacity;
+  uint64_t *ping_acks;
 
   /** parser for headers */
   grpc_chttp2_hpack_parser hpack_parser;
@@ -324,6 +350,13 @@ struct grpc_chttp2_transport {
 
   grpc_chttp2_write_cb *write_cb_pool;
 
+  /* bdp estimator */
+  grpc_bdp_estimator bdp_estimator;
+  grpc_pid_controller pid_controller;
+  grpc_closure start_bdp_ping_locked;
+  grpc_closure finish_bdp_ping_locked;
+  gpr_timespec last_pid_update;
+
   /* if non-NULL, close the transport with this error when writes are finished
    */
   grpc_error *close_transport_on_writes_finished;
@@ -362,12 +395,10 @@ struct grpc_chttp2_stream {
   /** HTTP2 stream id for this stream, or zero if one has not been assigned */
   uint32_t id;
 
-  /** window available for us to send to peer */
-  int64_t outgoing_window;
-  /** The number of bytes the upper layers have offered to receive.
-      As the upper layer offers more bytes, this value increases.
-      As bytes are read, this value decreases. */
-  uint32_t max_recv_bytes;
+  /** window available for us to send to peer, over or under the initial window
+    * size of the transport... ie:
+    * outgoing_window = outgoing_window_delta + transport.initial_window_size */
+  int64_t outgoing_window_delta;
   /** things the upper layers would like to send */
   grpc_metadata_batch *send_initial_metadata;
   grpc_closure *send_initial_metadata_finished;
@@ -428,8 +459,10 @@ struct grpc_chttp2_stream {
   grpc_error *forced_close_error;
   /** how many header frames have we received? */
   uint8_t header_frames_received;
-  /** window available for peer to send to us */
-  int64_t incoming_window;
+  /** window available for peer to send to us (as a delta on
+   * transport.initial_window_size)
+   * incoming_window = incoming_window_delta + transport.initial_window_size */
+  int64_t incoming_window_delta;
   /** parsing state for data frames */
   grpc_chttp2_data_parser data_parser;
   /** number of bytes received - reset at end of parse thread execution */
@@ -478,36 +511,43 @@ bool grpc_chttp2_list_add_writable_stream(grpc_chttp2_transport *t,
                                           grpc_chttp2_stream *s);
 /** Get a writable stream
     returns non-zero if there was a stream available */
-int grpc_chttp2_list_pop_writable_stream(grpc_chttp2_transport *t,
-                                         grpc_chttp2_stream **s);
+bool grpc_chttp2_list_pop_writable_stream(grpc_chttp2_transport *t,
+                                          grpc_chttp2_stream **s);
 bool grpc_chttp2_list_remove_writable_stream(
     grpc_chttp2_transport *t, grpc_chttp2_stream *s) GRPC_MUST_USE_RESULT;
 
 bool grpc_chttp2_list_add_writing_stream(grpc_chttp2_transport *t,
                                          grpc_chttp2_stream *s);
-int grpc_chttp2_list_have_writing_streams(grpc_chttp2_transport *t);
-int grpc_chttp2_list_pop_writing_stream(grpc_chttp2_transport *t,
-                                        grpc_chttp2_stream **s);
+bool grpc_chttp2_list_have_writing_streams(grpc_chttp2_transport *t);
+bool grpc_chttp2_list_pop_writing_stream(grpc_chttp2_transport *t,
+                                         grpc_chttp2_stream **s);
 
 void grpc_chttp2_list_add_written_stream(grpc_chttp2_transport *t,
                                          grpc_chttp2_stream *s);
-int grpc_chttp2_list_pop_written_stream(grpc_chttp2_transport *t,
-                                        grpc_chttp2_stream **s);
+bool grpc_chttp2_list_pop_written_stream(grpc_chttp2_transport *t,
+                                         grpc_chttp2_stream **s);
 
 void grpc_chttp2_list_add_waiting_for_concurrency(grpc_chttp2_transport *t,
                                                   grpc_chttp2_stream *s);
-int grpc_chttp2_list_pop_waiting_for_concurrency(grpc_chttp2_transport *t,
-                                                 grpc_chttp2_stream **s);
+bool grpc_chttp2_list_pop_waiting_for_concurrency(grpc_chttp2_transport *t,
+                                                  grpc_chttp2_stream **s);
 void grpc_chttp2_list_remove_waiting_for_concurrency(grpc_chttp2_transport *t,
                                                      grpc_chttp2_stream *s);
 
 void grpc_chttp2_list_add_stalled_by_transport(grpc_chttp2_transport *t,
                                                grpc_chttp2_stream *s);
-int grpc_chttp2_list_pop_stalled_by_transport(grpc_chttp2_transport *t,
-                                              grpc_chttp2_stream **s);
+bool grpc_chttp2_list_pop_stalled_by_transport(grpc_chttp2_transport *t,
+                                               grpc_chttp2_stream **s);
 void grpc_chttp2_list_remove_stalled_by_transport(grpc_chttp2_transport *t,
                                                   grpc_chttp2_stream *s);
 
+void grpc_chttp2_list_add_stalled_by_stream(grpc_chttp2_transport *t,
+                                            grpc_chttp2_stream *s);
+bool grpc_chttp2_list_pop_stalled_by_stream(grpc_chttp2_transport *t,
+                                            grpc_chttp2_stream **s);
+bool grpc_chttp2_list_remove_stalled_by_stream(grpc_chttp2_transport *t,
+                                               grpc_chttp2_stream *s);
+
 grpc_chttp2_stream *grpc_chttp2_parsing_lookup_stream(grpc_chttp2_transport *t,
                                                       uint32_t id);
 grpc_chttp2_stream *grpc_chttp2_parsing_accept_stream(grpc_exec_ctx *exec_ctx,
@@ -672,13 +712,23 @@ void grpc_chttp2_incoming_byte_stream_finished(
     grpc_error *error);
 
 void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
-                          const uint8_t *opaque_8bytes);
+                          uint64_t id);
+
+typedef enum {
+  /* don't initiate a transport write, but piggyback on the next one */
+  GRPC_CHTTP2_STREAM_WRITE_PIGGYBACK,
+  /* initiate a covered write */
+  GRPC_CHTTP2_STREAM_WRITE_INITIATE_COVERED,
+  /* initiate an uncovered write */
+  GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED
+} grpc_chttp2_stream_write_type;
 
 /** add a ref to the stream and add it to the writable list;
     ref will be dropped in writing.c */
 void grpc_chttp2_become_writable(grpc_exec_ctx *exec_ctx,
                                  grpc_chttp2_transport *t,
-                                 grpc_chttp2_stream *s, bool covered_by_poller,
+                                 grpc_chttp2_stream *s,
+                                 grpc_chttp2_stream_write_type type,
                                  const char *reason);
 
 void grpc_chttp2_cancel_stream(grpc_exec_ctx *exec_ctx,
diff --git a/src/core/ext/transport/chttp2/transport/parsing.c b/src/core/ext/transport/chttp2/transport/parsing.c
index f58cd696f9..24bd93067b 100644
--- a/src/core/ext/transport/chttp2/transport/parsing.c
+++ b/src/core/ext/transport/chttp2/transport/parsing.c
@@ -376,25 +376,45 @@ static grpc_error *update_incoming_window(grpc_exec_ctx *exec_ctx,
     return err;
   }
 
+  uint32_t target_incoming_window = GPR_MAX(
+      t->settings[GRPC_SENT_SETTINGS][GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE],
+      1024);
   GRPC_CHTTP2_FLOW_DEBIT_TRANSPORT("parse", t, incoming_window,
                                    incoming_frame_size);
+  if (t->incoming_window <= target_incoming_window / 2) {
+    grpc_chttp2_initiate_write(exec_ctx, t, false, "flow_control");
+  }
 
   if (s != NULL) {
-    if (incoming_frame_size > s->incoming_window) {
+    if (incoming_frame_size >
+        s->incoming_window_delta +
+            t->settings[GRPC_ACKED_SETTINGS]
+                       [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE]) {
       char *msg;
       gpr_asprintf(&msg,
                    "frame of size %d overflows incoming window of %" PRId64,
-                   t->incoming_frame_size, s->incoming_window);
+                   t->incoming_frame_size,
+                   s->incoming_window_delta +
+                       t->settings[GRPC_ACKED_SETTINGS]
+                                  [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE]);
       grpc_error *err = GRPC_ERROR_CREATE(msg);
       gpr_free(msg);
       return err;
     }
 
-    GRPC_CHTTP2_FLOW_DEBIT_STREAM("parse", t, s, incoming_window,
+    GRPC_CHTTP2_FLOW_DEBIT_STREAM("parse", t, s, incoming_window_delta,
                                   incoming_frame_size);
+    if ((int64_t)t->settings[GRPC_SENT_SETTINGS]
+                            [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE] +
+            (int64_t)s->incoming_window_delta - (int64_t)s->announce_window <=
+        (int64_t)t->settings[GRPC_SENT_SETTINGS]
+                            [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE] /
+            2) {
+      grpc_chttp2_become_writable(exec_ctx, t, s,
+                                  GRPC_CHTTP2_STREAM_WRITE_INITIATE_UNCOVERED,
+                                  "window-update-required");
+    }
     s->received_bytes += incoming_frame_size;
-    s->max_recv_bytes -=
-        (uint32_t)GPR_MIN(s->max_recv_bytes, incoming_frame_size);
   }
 
   return GRPC_ERROR_NONE;
diff --git a/src/core/ext/transport/chttp2/transport/stream_lists.c b/src/core/ext/transport/chttp2/transport/stream_lists.c
index a60264cc51..078818fb18 100644
--- a/src/core/ext/transport/chttp2/transport/stream_lists.c
+++ b/src/core/ext/transport/chttp2/transport/stream_lists.c
@@ -37,14 +37,14 @@
 
 /* core list management */
 
-static int stream_list_empty(grpc_chttp2_transport *t,
-                             grpc_chttp2_stream_list_id id) {
+static bool stream_list_empty(grpc_chttp2_transport *t,
+                              grpc_chttp2_stream_list_id id) {
   return t->lists[id].head == NULL;
 }
 
-static int stream_list_pop(grpc_chttp2_transport *t,
-                           grpc_chttp2_stream **stream,
-                           grpc_chttp2_stream_list_id id) {
+static bool stream_list_pop(grpc_chttp2_transport *t,
+                            grpc_chttp2_stream **stream,
+                            grpc_chttp2_stream_list_id id) {
   grpc_chttp2_stream *s = t->lists[id].head;
   if (s) {
     grpc_chttp2_stream *new_head = s->links[id].next;
@@ -124,8 +124,8 @@ bool grpc_chttp2_list_add_writable_stream(grpc_chttp2_transport *t,
   return stream_list_add(t, s, GRPC_CHTTP2_LIST_WRITABLE);
 }
 
-int grpc_chttp2_list_pop_writable_stream(grpc_chttp2_transport *t,
-                                         grpc_chttp2_stream **s) {
+bool grpc_chttp2_list_pop_writable_stream(grpc_chttp2_transport *t,
+                                          grpc_chttp2_stream **s) {
   return stream_list_pop(t, s, GRPC_CHTTP2_LIST_WRITABLE);
 }
 
@@ -139,12 +139,12 @@ bool grpc_chttp2_list_add_writing_stream(grpc_chttp2_transport *t,
   return stream_list_add(t, s, GRPC_CHTTP2_LIST_WRITING);
 }
 
-int grpc_chttp2_list_have_writing_streams(grpc_chttp2_transport *t) {
+bool grpc_chttp2_list_have_writing_streams(grpc_chttp2_transport *t) {
   return !stream_list_empty(t, GRPC_CHTTP2_LIST_WRITING);
 }
 
-int grpc_chttp2_list_pop_writing_stream(grpc_chttp2_transport *t,
-                                        grpc_chttp2_stream **s) {
+bool grpc_chttp2_list_pop_writing_stream(grpc_chttp2_transport *t,
+                                         grpc_chttp2_stream **s) {
   return stream_list_pop(t, s, GRPC_CHTTP2_LIST_WRITING);
 }
 
@@ -153,8 +153,8 @@ void grpc_chttp2_list_add_waiting_for_concurrency(grpc_chttp2_transport *t,
   stream_list_add(t, s, GRPC_CHTTP2_LIST_WAITING_FOR_CONCURRENCY);
 }
 
-int grpc_chttp2_list_pop_waiting_for_concurrency(grpc_chttp2_transport *t,
-                                                 grpc_chttp2_stream **s) {
+bool grpc_chttp2_list_pop_waiting_for_concurrency(grpc_chttp2_transport *t,
+                                                  grpc_chttp2_stream **s) {
   return stream_list_pop(t, s, GRPC_CHTTP2_LIST_WAITING_FOR_CONCURRENCY);
 }
 
@@ -168,8 +168,8 @@ void grpc_chttp2_list_add_stalled_by_transport(grpc_chttp2_transport *t,
   stream_list_add(t, s, GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT);
 }
 
-int grpc_chttp2_list_pop_stalled_by_transport(grpc_chttp2_transport *t,
-                                              grpc_chttp2_stream **s) {
+bool grpc_chttp2_list_pop_stalled_by_transport(grpc_chttp2_transport *t,
+                                               grpc_chttp2_stream **s) {
   return stream_list_pop(t, s, GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT);
 }
 
@@ -177,3 +177,18 @@ void grpc_chttp2_list_remove_stalled_by_transport(grpc_chttp2_transport *t,
                                                   grpc_chttp2_stream *s) {
   stream_list_maybe_remove(t, s, GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT);
 }
+
+void grpc_chttp2_list_add_stalled_by_stream(grpc_chttp2_transport *t,
+                                            grpc_chttp2_stream *s) {
+  stream_list_add(t, s, GRPC_CHTTP2_LIST_STALLED_BY_STREAM);
+}
+
+bool grpc_chttp2_list_pop_stalled_by_stream(grpc_chttp2_transport *t,
+                                            grpc_chttp2_stream **s) {
+  return stream_list_pop(t, s, GRPC_CHTTP2_LIST_STALLED_BY_STREAM);
+}
+
+bool grpc_chttp2_list_remove_stalled_by_stream(grpc_chttp2_transport *t,
+                                               grpc_chttp2_stream *s) {
+  return stream_list_maybe_remove(t, s, GRPC_CHTTP2_LIST_STALLED_BY_STREAM);
+}
diff --git a/src/core/ext/transport/chttp2/transport/writing.c b/src/core/ext/transport/chttp2/transport/writing.c
index 148e3844b5..05e6f59947 100644
--- a/src/core/ext/transport/chttp2/transport/writing.c
+++ b/src/core/ext/transport/chttp2/transport/writing.c
@@ -56,6 +56,75 @@ static void finish_write_cb(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   t->write_cb_pool = cb;
 }
 
+static void collapse_pings_from_into(grpc_chttp2_transport *t,
+                                     grpc_chttp2_ping_type ping_type,
+                                     grpc_chttp2_ping_queue *pq) {
+  for (size_t i = 0; i < GRPC_CHTTP2_PCL_COUNT; i++) {
+    grpc_closure_list_move(&t->ping_queues[ping_type].lists[i], &pq->lists[i]);
+  }
+}
+
+static void maybe_initiate_ping(grpc_exec_ctx *exec_ctx,
+                                grpc_chttp2_transport *t,
+                                grpc_chttp2_ping_type ping_type) {
+  grpc_chttp2_ping_queue *pq = &t->ping_queues[ping_type];
+  if (grpc_closure_list_empty(pq->lists[GRPC_CHTTP2_PCL_NEXT])) {
+    /* no ping needed: wait */
+    return;
+  }
+  if (!grpc_closure_list_empty(pq->lists[GRPC_CHTTP2_PCL_INFLIGHT])) {
+    /* ping already in-flight: wait */
+    if (grpc_http_trace || grpc_bdp_estimator_trace) {
+      gpr_log(GPR_DEBUG, "Ping delayed [%p]: already pinging", t->peer_string);
+    }
+    return;
+  }
+  if (t->ping_state.pings_before_data_required == 0 &&
+      t->ping_policy.max_pings_without_data != 0) {
+    /* need to send something of substance before sending a ping again */
+    if (grpc_http_trace || grpc_bdp_estimator_trace) {
+      gpr_log(GPR_DEBUG, "Ping delayed [%p]: too many recent pings: %d/%d",
+              t->peer_string, t->ping_state.pings_before_data_required,
+              t->ping_policy.max_pings_without_data);
+    }
+    return;
+  }
+  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+  gpr_timespec elapsed = gpr_time_sub(now, t->ping_state.last_ping_sent_time);
+  /*gpr_log(GPR_DEBUG, "elapsed:%d.%09d min:%d.%09d", (int)elapsed.tv_sec,
+          elapsed.tv_nsec, (int)t->ping_policy.min_time_between_pings.tv_sec,
+          (int)t->ping_policy.min_time_between_pings.tv_nsec);*/
+  if (gpr_time_cmp(elapsed, t->ping_policy.min_time_between_pings) < 0) {
+    /* not enough elapsed time between successive pings */
+    if (grpc_http_trace || grpc_bdp_estimator_trace) {
+      gpr_log(GPR_DEBUG,
+              "Ping delayed [%p]: not enough time elapsed since last ping",
+              t->peer_string);
+    }
+    return;
+  }
+  /* coalesce equivalent pings into this one */
+  switch (ping_type) {
+    case GRPC_CHTTP2_PING_BEFORE_TRANSPORT_WINDOW_UPDATE:
+      collapse_pings_from_into(t, GRPC_CHTTP2_PING_ON_NEXT_WRITE, pq);
+      break;
+    case GRPC_CHTTP2_PING_ON_NEXT_WRITE:
+      break;
+    case GRPC_CHTTP2_PING_TYPE_COUNT:
+      GPR_UNREACHABLE_CODE(break);
+  }
+  pq->inflight_id = t->ping_ctr * GRPC_CHTTP2_PING_TYPE_COUNT + ping_type;
+  t->ping_ctr++;
+  grpc_closure_list_sched(exec_ctx, &pq->lists[GRPC_CHTTP2_PCL_INITIATE]);
+  grpc_closure_list_move(&pq->lists[GRPC_CHTTP2_PCL_NEXT],
+                         &pq->lists[GRPC_CHTTP2_PCL_INFLIGHT]);
+  grpc_slice_buffer_add(&t->outbuf,
+                        grpc_chttp2_ping_create(false, pq->inflight_id));
+  t->ping_state.last_ping_sent_time = now;
+  t->ping_state.pings_before_data_required -=
+      (t->ping_state.pings_before_data_required != 0);
+}
+
 static void update_list(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                         grpc_chttp2_stream *s, int64_t send_bytes,
                         grpc_chttp2_write_cb **list, grpc_error *error) {
@@ -139,6 +208,8 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
       s->sent_initial_metadata = true;
       sent_initial_metadata = true;
       now_writing = true;
+      t->ping_state.pings_before_data_required =
+          t->ping_policy.max_pings_without_data;
     }
     /* send any window updates */
     if (s->announce_window > 0) {
@@ -146,15 +217,22 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
       grpc_slice_buffer_add(&t->outbuf,
                             grpc_chttp2_window_update_create(
                                 s->id, s->announce_window, &s->stats.outgoing));
+      t->ping_state.pings_before_data_required =
+          t->ping_policy.max_pings_without_data;
       GRPC_CHTTP2_FLOW_DEBIT_STREAM("write", t, s, announce_window, announce);
     }
     if (sent_initial_metadata) {
       /* send any body bytes, if allowed by flow control */
       if (s->flow_controlled_buffer.length > 0) {
-        uint32_t max_outgoing =
-            (uint32_t)GPR_MIN(t->settings[GRPC_ACKED_SETTINGS]
-                                         [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
-                              GPR_MIN(s->outgoing_window, t->outgoing_window));
+        uint32_t stream_outgoing_window = (uint32_t)GPR_MAX(
+            0,
+            s->outgoing_window_delta +
+                (int64_t)t->settings[GRPC_PEER_SETTINGS]
+                                    [GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE]);
+        uint32_t max_outgoing = (uint32_t)GPR_MIN(
+            t->settings[GRPC_ACKED_SETTINGS]
+                       [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
+            GPR_MIN(stream_outgoing_window, t->outgoing_window));
         if (max_outgoing > 0) {
           uint32_t send_bytes =
               (uint32_t)GPR_MIN(max_outgoing, s->flow_controlled_buffer.length);
@@ -167,10 +245,12 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
           grpc_chttp2_encode_data(s->id, &s->flow_controlled_buffer, send_bytes,
                                   is_last_frame, &s->stats.outgoing,
                                   &t->outbuf);
-          GRPC_CHTTP2_FLOW_DEBIT_STREAM("write", t, s, outgoing_window,
+          GRPC_CHTTP2_FLOW_DEBIT_STREAM("write", t, s, outgoing_window_delta,
                                         send_bytes);
           GRPC_CHTTP2_FLOW_DEBIT_TRANSPORT("write", t, outgoing_window,
                                            send_bytes);
+          t->ping_state.pings_before_data_required =
+              t->ping_policy.max_pings_without_data;
           if (is_last_frame) {
             s->send_trailing_metadata = NULL;
             s->sent_trailing_metadata = true;
@@ -189,6 +269,9 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
         } else if (t->outgoing_window == 0) {
           grpc_chttp2_list_add_stalled_by_transport(t, s);
           now_writing = true;
+        } else if (stream_outgoing_window == 0) {
+          grpc_chttp2_list_add_stalled_by_stream(t, s);
+          now_writing = true;
         }
       }
       if (s->send_trailing_metadata != NULL &&
@@ -227,15 +310,32 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
 
   /* if the grpc_chttp2_transport is ready to send a window update, do so here
      also; 3/4 is a magic number that will likely get tuned soon */
-  if (t->announce_incoming_window > 0) {
-    uint32_t announced =
-        (uint32_t)GPR_MIN(t->announce_incoming_window, UINT32_MAX);
-    GRPC_CHTTP2_FLOW_DEBIT_TRANSPORT("write", t, announce_incoming_window,
-                                     announced);
+  uint32_t target_incoming_window = GPR_MAX(
+      t->settings[GRPC_SENT_SETTINGS][GRPC_CHTTP2_SETTINGS_INITIAL_WINDOW_SIZE],
+      1024);
+  uint32_t threshold_to_send_transport_window_update =
+      t->outbuf.count > 0 ? 3 * target_incoming_window / 4
+                          : target_incoming_window / 2;
+  if (t->incoming_window <= threshold_to_send_transport_window_update) {
+    maybe_initiate_ping(exec_ctx, t,
+                        GRPC_CHTTP2_PING_BEFORE_TRANSPORT_WINDOW_UPDATE);
+    uint32_t announced = (uint32_t)GPR_CLAMP(
+        target_incoming_window - t->incoming_window, 0, UINT32_MAX);
+    GRPC_CHTTP2_FLOW_CREDIT_TRANSPORT("write", t, incoming_window, announced);
     grpc_transport_one_way_stats throwaway_stats;
     grpc_slice_buffer_add(&t->outbuf, grpc_chttp2_window_update_create(
                                           0, announced, &throwaway_stats));
+    t->ping_state.pings_before_data_required =
+        t->ping_policy.max_pings_without_data;
+  }
+
+  for (size_t i = 0; i < t->ping_ack_count; i++) {
+    grpc_slice_buffer_add(&t->outbuf,
+                          grpc_chttp2_ping_create(1, t->ping_acks[i]));
   }
+  t->ping_ack_count = 0;
+
+  maybe_initiate_ping(exec_ctx, t, GRPC_CHTTP2_PING_ON_NEXT_WRITE);
 
   GPR_TIMER_END("grpc_chttp2_begin_write", 0);
 
diff --git a/src/core/lib/iomgr/closure.c b/src/core/lib/iomgr/closure.c
index 8e4efd3370..509c1ff95d 100644
--- a/src/core/lib/iomgr/closure.c
+++ b/src/core/lib/iomgr/closure.c
@@ -51,20 +51,22 @@ void grpc_closure_list_init(grpc_closure_list *closure_list) {
   closure_list->head = closure_list->tail = NULL;
 }
 
-void grpc_closure_list_append(grpc_closure_list *closure_list,
+bool grpc_closure_list_append(grpc_closure_list *closure_list,
                               grpc_closure *closure, grpc_error *error) {
   if (closure == NULL) {
     GRPC_ERROR_UNREF(error);
-    return;
+    return false;
   }
   closure->error_data.error = error;
   closure->next_data.next = NULL;
-  if (closure_list->head == NULL) {
+  bool was_empty = (closure_list->head == NULL);
+  if (was_empty) {
     closure_list->head = closure;
   } else {
     closure_list->tail->next_data.next = closure;
   }
   closure_list->tail = closure;
+  return was_empty;
 }
 
 void grpc_closure_list_fail_all(grpc_closure_list *list,
diff --git a/src/core/lib/iomgr/closure.h b/src/core/lib/iomgr/closure.h
index 6748b21e59..2510d50b42 100644
--- a/src/core/lib/iomgr/closure.h
+++ b/src/core/lib/iomgr/closure.h
@@ -116,8 +116,9 @@ grpc_closure *grpc_closure_create(grpc_iomgr_cb_func cb, void *cb_arg,
 void grpc_closure_list_init(grpc_closure_list *list);
 
 /** add \a closure to the end of \a list
-    and set \a closure's result to \a error */
-void grpc_closure_list_append(grpc_closure_list *list, grpc_closure *closure,
+    and set \a closure's result to \a error
+    Returns true if \a list becomes non-empty */
+bool grpc_closure_list_append(grpc_closure_list *list, grpc_closure *closure,
                               grpc_error *error);
 
 /** force all success bits in \a list to false */
diff --git a/src/core/lib/iomgr/resource_quota.c b/src/core/lib/iomgr/resource_quota.c
index d5995a5ac6..2cc979467f 100644
--- a/src/core/lib/iomgr/resource_quota.c
+++ b/src/core/lib/iomgr/resource_quota.c
@@ -33,6 +33,8 @@
 
 #include "src/core/lib/iomgr/resource_quota.h"
 
+#include <limits.h>
+#include <stdint.h>
 #include <string.h>
 
 #include <grpc/support/alloc.h>
@@ -44,6 +46,8 @@
 
 int grpc_resource_quota_trace = 0;
 
+#define MEMORY_USAGE_ESTIMATION_MAX 65536
+
 /* Internal linked list pointers for a resource user */
 typedef struct {
   grpc_resource_user *next;
@@ -126,9 +130,12 @@ struct grpc_resource_quota {
   /* refcount */
   gpr_refcount refs;
 
+  /* estimate of current memory usage
+     scaled to the range [0..RESOURCE_USAGE_ESTIMATION_MAX] */
+  gpr_atm memory_usage_estimation;
+
   /* Master combiner lock: all activity on a quota executes under this combiner
-   * (so no mutex is needed for this data structure)
-   */
+   * (so no mutex is needed for this data structure) */
   grpc_combiner *combiner;
   /* Size of the resource quota */
   int64_t size;
@@ -269,6 +276,16 @@ static void rq_step_sched(grpc_exec_ctx *exec_ctx,
                      GRPC_ERROR_NONE);
 }
 
+/* update the atomically available resource estimate - use no barriers since
+   timeliness of delivery really doesn't matter much */
+static void rq_update_estimate(grpc_resource_quota *resource_quota) {
+  gpr_atm_no_barrier_store(&resource_quota->memory_usage_estimation,
+                           (gpr_atm)((1.0 -
+                                      ((double)resource_quota->free_pool) /
+                                          ((double)resource_quota->size)) *
+                                     MEMORY_USAGE_ESTIMATION_MAX));
+}
+
 /* returns true if all allocations are completed */
 static bool rq_alloc(grpc_exec_ctx *exec_ctx,
                      grpc_resource_quota *resource_quota) {
@@ -281,6 +298,7 @@ static bool rq_alloc(grpc_exec_ctx *exec_ctx,
       int64_t amt = -resource_user->free_pool;
       resource_user->free_pool = 0;
       resource_quota->free_pool -= amt;
+      rq_update_estimate(resource_quota);
       if (grpc_resource_quota_trace) {
         gpr_log(GPR_DEBUG, "RQ %s %s: grant alloc %" PRId64
                            " bytes; rq_free_pool -> %" PRId64,
@@ -315,6 +333,7 @@ static bool rq_reclaim_from_per_user_free_pool(
       int64_t amt = resource_user->free_pool;
       resource_user->free_pool = 0;
       resource_quota->free_pool += amt;
+      rq_update_estimate(resource_quota);
       if (grpc_resource_quota_trace) {
         gpr_log(GPR_DEBUG, "RQ %s %s: reclaim_from_per_user_free_pool %" PRId64
                            " bytes; rq_free_pool -> %" PRId64,
@@ -531,6 +550,7 @@ static void rq_resize(grpc_exec_ctx *exec_ctx, void *args, grpc_error *error) {
   int64_t delta = a->size - a->resource_quota->size;
   a->resource_quota->size += delta;
   a->resource_quota->free_pool += delta;
+  rq_update_estimate(a->resource_quota);
   rq_step_sched(exec_ctx, a->resource_quota);
   grpc_resource_quota_unref_internal(exec_ctx, a->resource_quota);
   gpr_free(a);
@@ -557,6 +577,7 @@ grpc_resource_quota *grpc_resource_quota_create(const char *name) {
   resource_quota->size = INT64_MAX;
   resource_quota->step_scheduled = false;
   resource_quota->reclaiming = false;
+  gpr_atm_no_barrier_store(&resource_quota->memory_usage_estimation, 0);
   if (name != NULL) {
     resource_quota->name = gpr_strdup(name);
   } else {
@@ -602,6 +623,13 @@ void grpc_resource_quota_ref(grpc_resource_quota *resource_quota) {
   grpc_resource_quota_ref_internal(resource_quota);
 }
 
+double grpc_resource_quota_get_memory_pressure(
+    grpc_resource_quota *resource_quota) {
+  return ((double)(gpr_atm_no_barrier_load(
+             &resource_quota->memory_usage_estimation))) /
+         ((double)MEMORY_USAGE_ESTIMATION_MAX);
+}
+
 /* Public API */
 void grpc_resource_quota_resize(grpc_resource_quota *resource_quota,
                                 size_t size) {
diff --git a/src/core/lib/iomgr/resource_quota.h b/src/core/lib/iomgr/resource_quota.h
index d1127ce9ea..b9f62cbf83 100644
--- a/src/core/lib/iomgr/resource_quota.h
+++ b/src/core/lib/iomgr/resource_quota.h
@@ -84,6 +84,12 @@ void grpc_resource_quota_unref_internal(grpc_exec_ctx *exec_ctx,
 grpc_resource_quota *grpc_resource_quota_from_channel_args(
     const grpc_channel_args *channel_args);
 
+/* Return a number indicating current memory pressure:
+   0.0 ==> no memory usage
+   1.0 ==> maximum memory usage */
+double grpc_resource_quota_get_memory_pressure(
+    grpc_resource_quota *resource_quota);
+
 typedef struct grpc_resource_user grpc_resource_user;
 
 grpc_resource_user *grpc_resource_user_create(
diff --git a/src/core/lib/support/log_posix.c b/src/core/lib/support/log_posix.c
index f972da0887..79458dd7a3 100644
--- a/src/core/lib/support/log_posix.c
+++ b/src/core/lib/support/log_posix.c
@@ -37,6 +37,7 @@
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
 #include <grpc/support/time.h>
 #include <pthread.h>
 #include <stdarg.h>
@@ -93,10 +94,13 @@ void gpr_default_log(gpr_log_func_args *args) {
     strcpy(time_buffer, "error:strftime");
   }
 
-  fprintf(stderr, "%s%s.%09d %7tu %s:%d] %s\n",
-          gpr_log_severity_string(args->severity), time_buffer,
-          (int)(now.tv_nsec), gettid(), display_file, args->line,
-          args->message);
+  char *prefix;
+  gpr_asprintf(&prefix, "%s%s.%09d %7tu %s:%d]",
+               gpr_log_severity_string(args->severity), time_buffer,
+               (int)(now.tv_nsec), gettid(), display_file, args->line);
+
+  fprintf(stderr, "%-70s %s\n", prefix, args->message);
+  gpr_free(prefix);
 }
 
 #endif /* defined(GPR_POSIX_LOG) */
diff --git a/src/core/lib/surface/init.c b/src/core/lib/surface/init.c
index 787e4d0dd2..b338ac4c48 100644
--- a/src/core/lib/surface/init.c
+++ b/src/core/lib/surface/init.c
@@ -63,6 +63,7 @@
 #include "src/core/lib/surface/init.h"
 #include "src/core/lib/surface/lame_client.h"
 #include "src/core/lib/surface/server.h"
+#include "src/core/lib/transport/bdp_estimator.h"
 #include "src/core/lib/transport/connectivity_state.h"
 #include "src/core/lib/transport/transport_impl.h"
 
@@ -192,6 +193,7 @@ void grpc_init(void) {
     grpc_register_tracer("queue_pluck", &grpc_cq_pluck_trace);
     grpc_register_tracer("combiner", &grpc_combiner_trace);
     grpc_register_tracer("server_channel", &grpc_server_channel_trace);
+    grpc_register_tracer("bdp_estimator", &grpc_bdp_estimator_trace);
     // Default pluck trace to 1
     grpc_cq_pluck_trace = 1;
     grpc_register_tracer("queue_timeout", &grpc_cq_event_timeout_trace);
diff --git a/src/core/lib/transport/bdp_estimator.c b/src/core/lib/transport/bdp_estimator.c
new file mode 100644
index 0000000000..e1483677fd
--- /dev/null
+++ b/src/core/lib/transport/bdp_estimator.c
@@ -0,0 +1,104 @@
+/*
+ *
+ * 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 "src/core/lib/transport/bdp_estimator.h"
+
+#include <stdlib.h>
+
+#include <grpc/support/log.h>
+#include <grpc/support/useful.h>
+
+int grpc_bdp_estimator_trace = 0;
+
+void grpc_bdp_estimator_init(grpc_bdp_estimator *estimator, const char *name) {
+  estimator->estimate = 65536;
+  estimator->ping_state = GRPC_BDP_PING_UNSCHEDULED;
+  estimator->name = name;
+}
+
+bool grpc_bdp_estimator_get_estimate(grpc_bdp_estimator *estimator,
+                                     int64_t *estimate) {
+  *estimate = estimator->estimate;
+  return true;
+}
+
+bool grpc_bdp_estimator_add_incoming_bytes(grpc_bdp_estimator *estimator,
+                                           int64_t num_bytes) {
+  estimator->accumulator += num_bytes;
+  switch (estimator->ping_state) {
+    case GRPC_BDP_PING_UNSCHEDULED:
+      return true;
+    case GRPC_BDP_PING_SCHEDULED:
+      return false;
+    case GRPC_BDP_PING_STARTED:
+      return false;
+  }
+  GPR_UNREACHABLE_CODE(return false);
+}
+
+void grpc_bdp_estimator_schedule_ping(grpc_bdp_estimator *estimator) {
+  if (grpc_bdp_estimator_trace) {
+    gpr_log(GPR_DEBUG, "bdp[%s]:sched acc=%" PRId64 " est=%" PRId64,
+            estimator->name, estimator->accumulator, estimator->estimate);
+  }
+  GPR_ASSERT(estimator->ping_state == GRPC_BDP_PING_UNSCHEDULED);
+  estimator->ping_state = GRPC_BDP_PING_SCHEDULED;
+  estimator->accumulator = 0;
+}
+
+void grpc_bdp_estimator_start_ping(grpc_bdp_estimator *estimator) {
+  if (grpc_bdp_estimator_trace) {
+    gpr_log(GPR_DEBUG, "bdp[%s]:start acc=%" PRId64 " est=%" PRId64,
+            estimator->name, estimator->accumulator, estimator->estimate);
+  }
+  GPR_ASSERT(estimator->ping_state == GRPC_BDP_PING_SCHEDULED);
+  estimator->ping_state = GRPC_BDP_PING_STARTED;
+  estimator->accumulator = 0;
+}
+
+void grpc_bdp_estimator_complete_ping(grpc_bdp_estimator *estimator) {
+  if (grpc_bdp_estimator_trace) {
+    gpr_log(GPR_DEBUG, "bdp[%s]:complete acc=%" PRId64 " est=%" PRId64,
+            estimator->name, estimator->accumulator, estimator->estimate);
+  }
+  GPR_ASSERT(estimator->ping_state == GRPC_BDP_PING_STARTED);
+  if (estimator->accumulator > 2 * estimator->estimate / 3) {
+    estimator->estimate *= 2;
+    if (grpc_bdp_estimator_trace) {
+      gpr_log(GPR_DEBUG, "bdp[%s]: estimate increased to %" PRId64,
+              estimator->name, estimator->estimate);
+    }
+  }
+  estimator->ping_state = GRPC_BDP_PING_UNSCHEDULED;
+  estimator->accumulator = 0;
+}
diff --git a/src/core/lib/transport/bdp_estimator.h b/src/core/lib/transport/bdp_estimator.h
new file mode 100644
index 0000000000..bcaf899910
--- /dev/null
+++ b/src/core/lib/transport/bdp_estimator.h
@@ -0,0 +1,76 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_TRANSPORT_BDP_ESTIMATOR_H
+#define GRPC_CORE_LIB_TRANSPORT_BDP_ESTIMATOR_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#define GRPC_BDP_SAMPLES 16
+#define GRPC_BDP_MIN_SAMPLES_FOR_ESTIMATE 3
+
+extern int grpc_bdp_estimator_trace;
+
+typedef enum {
+  GRPC_BDP_PING_UNSCHEDULED,
+  GRPC_BDP_PING_SCHEDULED,
+  GRPC_BDP_PING_STARTED
+} grpc_bdp_estimator_ping_state;
+
+typedef struct grpc_bdp_estimator {
+  grpc_bdp_estimator_ping_state ping_state;
+  int64_t accumulator;
+  int64_t estimate;
+  const char *name;
+} grpc_bdp_estimator;
+
+void grpc_bdp_estimator_init(grpc_bdp_estimator *estimator, const char *name);
+
+// Returns true if a reasonable estimate could be obtained
+bool grpc_bdp_estimator_get_estimate(grpc_bdp_estimator *estimator,
+                                     int64_t *estimate);
+// Returns true if the user should schedule a ping
+bool grpc_bdp_estimator_add_incoming_bytes(grpc_bdp_estimator *estimator,
+                                           int64_t num_bytes);
+// Schedule a ping: call in response to receiving a true from
+// grpc_bdp_estimator_add_incoming_bytes once a ping has been scheduled by a
+// transport (but not necessarily started)
+void grpc_bdp_estimator_schedule_ping(grpc_bdp_estimator *estimator);
+// Start a ping: call after calling grpc_bdp_estimator_schedule_ping and once
+// the ping is on the wire
+void grpc_bdp_estimator_start_ping(grpc_bdp_estimator *estimator);
+// Completes a previously started ping
+void grpc_bdp_estimator_complete_ping(grpc_bdp_estimator *estimator);
+
+#endif
diff --git a/src/core/lib/transport/pid_controller.c b/src/core/lib/transport/pid_controller.c
index 3cef225d4b..19cb1c0b36 100644
--- a/src/core/lib/transport/pid_controller.c
+++ b/src/core/lib/transport/pid_controller.c
@@ -32,26 +32,46 @@
  */
 
 #include "src/core/lib/transport/pid_controller.h"
+#include <grpc/support/useful.h>
 
 void grpc_pid_controller_init(grpc_pid_controller *pid_controller,
-                              double gain_p, double gain_i, double gain_d) {
-  pid_controller->gain_p = gain_p;
-  pid_controller->gain_i = gain_i;
-  pid_controller->gain_d = gain_d;
+                              grpc_pid_controller_args args) {
+  pid_controller->args = args;
+  pid_controller->last_control_value = args.initial_control_value;
   grpc_pid_controller_reset(pid_controller);
 }
 
 void grpc_pid_controller_reset(grpc_pid_controller *pid_controller) {
   pid_controller->last_error = 0.0;
+  pid_controller->last_dc_dt = 0.0;
   pid_controller->error_integral = 0.0;
 }
 
 double grpc_pid_controller_update(grpc_pid_controller *pid_controller,
                                   double error, double dt) {
-  pid_controller->error_integral += error * dt;
+  /* integrate error using the trapezoid rule */
+  pid_controller->error_integral +=
+      dt * (pid_controller->last_error + error) * 0.5;
+  pid_controller->error_integral = GPR_CLAMP(
+      pid_controller->error_integral, -pid_controller->args.integral_range,
+      pid_controller->args.integral_range);
   double diff_error = (error - pid_controller->last_error) / dt;
+  /* calculate derivative of control value vs time */
+  double dc_dt = pid_controller->args.gain_p * error +
+                 pid_controller->args.gain_i * pid_controller->error_integral +
+                 pid_controller->args.gain_d * diff_error;
+  /* and perform trapezoidal integration */
+  double new_control_value = pid_controller->last_control_value +
+                             dt * (pid_controller->last_dc_dt + dc_dt) * 0.5;
+  new_control_value =
+      GPR_CLAMP(new_control_value, pid_controller->args.min_control_value,
+                pid_controller->args.max_control_value);
   pid_controller->last_error = error;
-  return dt * (pid_controller->gain_p * error +
-               pid_controller->gain_i * pid_controller->error_integral +
-               pid_controller->gain_d * diff_error);
+  pid_controller->last_dc_dt = dc_dt;
+  pid_controller->last_control_value = new_control_value;
+  return new_control_value;
+}
+
+double grpc_pid_controller_last(grpc_pid_controller *pid_controller) {
+  return pid_controller->last_control_value;
 }
diff --git a/src/core/lib/transport/pid_controller.h b/src/core/lib/transport/pid_controller.h
index 83c82d6471..0a86521e90 100644
--- a/src/core/lib/transport/pid_controller.h
+++ b/src/core/lib/transport/pid_controller.h
@@ -45,20 +45,33 @@ typedef struct {
   double gain_p;
   double gain_i;
   double gain_d;
+  double initial_control_value;
+  double min_control_value;
+  double max_control_value;
+  double integral_range;
+} grpc_pid_controller_args;
+
+typedef struct {
   double last_error;
   double error_integral;
+  double last_control_value;
+  double last_dc_dt;
+  grpc_pid_controller_args args;
 } grpc_pid_controller;
 
 /** Initialize the controller */
 void grpc_pid_controller_init(grpc_pid_controller *pid_controller,
-                              double gain_p, double gain_i, double gain_d);
+                              grpc_pid_controller_args args);
 
 /** Reset the controller: useful when things have changed significantly */
 void grpc_pid_controller_reset(grpc_pid_controller *pid_controller);
 
 /** Update the controller: given a current error estimate, and the time since
-    the last update, returns a delta to the control value */
+    the last update, returns a new control value */
 double grpc_pid_controller_update(grpc_pid_controller *pid_controller,
                                   double error, double dt);
 
+/** Returns the last control value calculated */
+double grpc_pid_controller_last(grpc_pid_controller *pid_controller);
+
 #endif /* GRPC_CORE_LIB_TRANSPORT_PID_CONTROLLER_H */
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index 68e40da4cf..6bca3ed1a5 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -180,6 +180,7 @@ CORE_SOURCE_FILES = [
   'src/core/lib/surface/server.c',
   'src/core/lib/surface/validate_metadata.c',
   'src/core/lib/surface/version.c',
+  'src/core/lib/transport/bdp_estimator.c',
   'src/core/lib/transport/byte_stream.c',
   'src/core/lib/transport/connectivity_state.c',
   'src/core/lib/transport/error_utils.c',
diff --git a/templates/tools/run_tests/generated/tests.json.template b/templates/tools/run_tests/generated/tests.json.template
index 1e21465dd2..2815dbb9b3 100644
--- a/templates/tools/run_tests/generated/tests.json.template
+++ b/templates/tools/run_tests/generated/tests.json.template
@@ -11,7 +11,7 @@
                  "gtest": tgt.gtest,
                  "exclude_configs": tgt.get("exclude_configs", []),
                  "exclude_iomgrs": tgt.get("exclude_iomgrs", []),
-                 "args": [],
+                 "args": tgt.get("args", []),
                  "flaky": tgt.flaky,
                  "cpu_cost": tgt.get("cpu_cost", 1.0)}
                 for tgt in targets
diff --git a/test/core/client_channel/lb_policies_test.c b/test/core/client_channel/lb_policies_test.c
index efa4ad7ee6..057b90ec84 100644
--- a/test/core/client_channel/lb_policies_test.c
+++ b/test/core/client_channel/lb_policies_test.c
@@ -517,7 +517,7 @@ static grpc_channel *create_client(const servers_fixture *f) {
   grpc_channel *client;
   char *client_hostport;
   char *servers_hostports_str;
-  grpc_arg arg_array[2];
+  grpc_arg arg_array[3];
   grpc_channel_args args;
 
   servers_hostports_str = gpr_strjoin_sep((const char **)f->servers_hostports,
@@ -530,7 +530,10 @@ static grpc_channel *create_client(const servers_fixture *f) {
   arg_array[1].type = GRPC_ARG_STRING;
   arg_array[1].key = GRPC_ARG_LB_POLICY_NAME;
   arg_array[1].value.string = "ROUND_ROBIN";
-  args.num_args = 2;
+  arg_array[2].type = GRPC_ARG_INTEGER;
+  arg_array[2].key = GRPC_ARG_HTTP2_MIN_TIME_BETWEEN_PINGS_MS;
+  arg_array[2].value.integer = 0;
+  args.num_args = GPR_ARRAY_SIZE(arg_array);
   args.args = arg_array;
 
   client = grpc_insecure_channel_create(client_hostport, &args, NULL);
diff --git a/test/core/end2end/bad_server_response_test.c b/test/core/end2end/bad_server_response_test.c
index d5f428eb82..42d960c428 100644
--- a/test/core/end2end/bad_server_response_test.c
+++ b/test/core/end2end/bad_server_response_test.c
@@ -135,7 +135,7 @@ static void handle_read(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
 
   gpr_log(GPR_DEBUG, "got %" PRIuPTR " bytes, expected %" PRIuPTR " bytes",
           state.incoming_data_length, EXPECTED_INCOMING_DATA_LENGTH);
-  if (state.incoming_data_length > EXPECTED_INCOMING_DATA_LENGTH) {
+  if (state.incoming_data_length >= EXPECTED_INCOMING_DATA_LENGTH) {
     handle_write(exec_ctx);
   } else {
     grpc_endpoint_read(exec_ctx, state.tcp, &state.temp_incoming_buffer,
diff --git a/test/core/end2end/tests/ping.c b/test/core/end2end/tests/ping.c
index 61f4337f2f..f5bfac2255 100644
--- a/test/core/end2end/tests/ping.c
+++ b/test/core/end2end/tests/ping.c
@@ -37,6 +37,7 @@
 #include <grpc/support/sync.h>
 #include <grpc/support/thd.h>
 #include <grpc/support/time.h>
+#include <grpc/support/useful.h>
 
 #include "test/core/end2end/cq_verifier.h"
 
@@ -48,7 +49,15 @@ static void test_ping(grpc_end2end_test_config config) {
   grpc_connectivity_state state = GRPC_CHANNEL_IDLE;
   int i;
 
-  config.init_client(&f, NULL);
+  grpc_arg a[] = {{.type = GRPC_ARG_INTEGER,
+                   .key = GRPC_ARG_HTTP2_MIN_TIME_BETWEEN_PINGS_MS,
+                   .value.integer = 0},
+                  {.type = GRPC_ARG_INTEGER,
+                   .key = GRPC_ARG_HTTP2_MAX_PINGS_WITHOUT_DATA,
+                   .value.integer = 20}};
+  grpc_channel_args client_args = {.num_args = GPR_ARRAY_SIZE(a), .args = a};
+
+  config.init_client(&f, &client_args);
   config.init_server(&f, NULL);
 
   grpc_channel_ping(f.client, f.cq, tag(0), NULL);
diff --git a/test/core/end2end/tests/resource_quota_server.c b/test/core/end2end/tests/resource_quota_server.c
index 3fbe0aa0d0..4f9ed7a3a1 100644
--- a/test/core/end2end/tests/resource_quota_server.c
+++ b/test/core/end2end/tests/resource_quota_server.c
@@ -160,6 +160,7 @@ void resource_quota_server(grpc_end2end_test_config config) {
   int pending_server_end_calls = 0;
   int cancelled_calls_on_client = 0;
   int cancelled_calls_on_server = 0;
+  int deadline_exceeded = 0;
 
   grpc_byte_buffer *request_payload =
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
@@ -247,6 +248,9 @@ void resource_quota_server(grpc_end2end_test_config config) {
         case GRPC_STATUS_RESOURCE_EXHAUSTED:
           cancelled_calls_on_client++;
           break;
+        case GRPC_STATUS_DEADLINE_EXCEEDED:
+          deadline_exceeded++;
+          break;
         case GRPC_STATUS_OK:
           break;
         default:
@@ -343,20 +347,19 @@ void resource_quota_server(grpc_end2end_test_config config) {
     }
   }
 
-  gpr_log(
-      GPR_INFO,
-      "Done. %d total calls: %d cancelled at server, %d cancelled at client.",
-      NUM_CALLS, cancelled_calls_on_server, cancelled_calls_on_client);
-
-  /* The call may be cancelled after the server has sent its status but before
-   * the client has received it. This means that we should see strictly more
-   * failures on the client than on the server. */
-  GPR_ASSERT(cancelled_calls_on_client >= cancelled_calls_on_server);
+  gpr_log(GPR_INFO,
+          "Done. %d total calls: %d cancelled at server, %d cancelled at "
+          "client, %d timed out.",
+          NUM_CALLS, cancelled_calls_on_server, cancelled_calls_on_client,
+          deadline_exceeded);
 
   grpc_byte_buffer_destroy(request_payload);
   grpc_slice_unref(request_payload_slice);
   grpc_resource_quota_unref(resource_quota);
 
+  end_test(&f);
+  config.tear_down_data(&f);
+
   free(client_calls);
   free(server_calls);
   free(initial_metadata_recv);
@@ -367,9 +370,6 @@ void resource_quota_server(grpc_end2end_test_config config) {
   free(details);
   free(request_payload_recv);
   free(was_cancelled);
-
-  end_test(&f);
-  config.tear_down_data(&f);
 }
 
 void resource_quota_server_pre_init(void) {}
diff --git a/test/core/transport/bdp_estimator_test.c b/test/core/transport/bdp_estimator_test.c
new file mode 100644
index 0000000000..f55a3ca643
--- /dev/null
+++ b/test/core/transport/bdp_estimator_test.c
@@ -0,0 +1,153 @@
+/*
+ *
+ * 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 "src/core/lib/transport/bdp_estimator.h"
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/useful.h>
+#include <limits.h>
+#include "src/core/lib/support/string.h"
+#include "test/core/util/test_config.h"
+
+static void test_noop(void) {
+  gpr_log(GPR_INFO, "test_noop");
+  grpc_bdp_estimator est;
+  grpc_bdp_estimator_init(&est, "test");
+}
+
+static void test_get_estimate_no_samples(void) {
+  gpr_log(GPR_INFO, "test_get_estimate_no_samples");
+  grpc_bdp_estimator est;
+  grpc_bdp_estimator_init(&est, "test");
+  int64_t estimate;
+  grpc_bdp_estimator_get_estimate(&est, &estimate);
+}
+
+static void add_samples(grpc_bdp_estimator *estimator, int64_t *samples,
+                        size_t n) {
+  GPR_ASSERT(grpc_bdp_estimator_add_incoming_bytes(estimator, 1234567) == true);
+  grpc_bdp_estimator_schedule_ping(estimator);
+  grpc_bdp_estimator_start_ping(estimator);
+  for (size_t i = 0; i < n; i++) {
+    GPR_ASSERT(grpc_bdp_estimator_add_incoming_bytes(estimator, samples[i]) ==
+               false);
+  }
+  grpc_bdp_estimator_complete_ping(estimator);
+}
+
+static void add_sample(grpc_bdp_estimator *estimator, int64_t sample) {
+  add_samples(estimator, &sample, 1);
+}
+
+static void test_get_estimate_1_sample(void) {
+  gpr_log(GPR_INFO, "test_get_estimate_1_sample");
+  grpc_bdp_estimator est;
+  grpc_bdp_estimator_init(&est, "test");
+  add_sample(&est, 100);
+  int64_t estimate;
+  grpc_bdp_estimator_get_estimate(&est, &estimate);
+}
+
+static void test_get_estimate_2_samples(void) {
+  gpr_log(GPR_INFO, "test_get_estimate_2_samples");
+  grpc_bdp_estimator est;
+  grpc_bdp_estimator_init(&est, "test");
+  add_sample(&est, 100);
+  add_sample(&est, 100);
+  int64_t estimate;
+  grpc_bdp_estimator_get_estimate(&est, &estimate);
+}
+
+static int64_t get_estimate(grpc_bdp_estimator *estimator) {
+  int64_t out;
+  GPR_ASSERT(grpc_bdp_estimator_get_estimate(estimator, &out));
+  return out;
+}
+
+static void test_get_estimate_3_samples(void) {
+  gpr_log(GPR_INFO, "test_get_estimate_3_samples");
+  grpc_bdp_estimator est;
+  grpc_bdp_estimator_init(&est, "test");
+  add_sample(&est, 100);
+  add_sample(&est, 100);
+  add_sample(&est, 100);
+  int64_t estimate;
+  grpc_bdp_estimator_get_estimate(&est, &estimate);
+}
+
+static int64_t next_pow_2(int64_t v) {
+  v--;
+  v |= v >> 1;
+  v |= v >> 2;
+  v |= v >> 4;
+  v |= v >> 8;
+  v |= v >> 16;
+  v |= v >> 32;
+  v++;
+  return v;
+}
+
+static void test_get_estimate_random_values(size_t n) {
+  gpr_log(GPR_INFO, "test_get_estimate_random_values(%" PRIdPTR ")", n);
+  grpc_bdp_estimator est;
+  grpc_bdp_estimator_init(&est, "test");
+  int min = INT_MAX;
+  int max = 65535;  // Windows rand() has limited range, make sure the ASSERT
+                    // passes
+  for (size_t i = 0; i < n; i++) {
+    int sample = rand();
+    if (sample < min) min = sample;
+    if (sample > max) max = sample;
+    add_sample(&est, sample);
+    if (i >= 3) {
+      gpr_log(GPR_DEBUG, "est:%" PRId64 " min:%d max:%d", get_estimate(&est),
+              min, max);
+      GPR_ASSERT(get_estimate(&est) <= 2 * next_pow_2(max));
+    }
+  }
+}
+
+int main(int argc, char **argv) {
+  grpc_test_init(argc, argv);
+  test_noop();
+  test_get_estimate_no_samples();
+  test_get_estimate_1_sample();
+  test_get_estimate_2_samples();
+  test_get_estimate_3_samples();
+  for (size_t i = 3; i < 1000; i = i * 3 / 2) {
+    test_get_estimate_random_values(i);
+  }
+  return 0;
+}
diff --git a/test/core/transport/pid_controller_test.c b/test/core/transport/pid_controller_test.c
index 9614983b00..831343c815 100644
--- a/test/core/transport/pid_controller_test.c
+++ b/test/core/transport/pid_controller_test.c
@@ -33,6 +33,7 @@
 
 #include "src/core/lib/transport/pid_controller.h"
 
+#include <float.h>
 #include <math.h>
 
 #include <grpc/support/alloc.h>
@@ -45,7 +46,14 @@
 static void test_noop(void) {
   gpr_log(GPR_INFO, "test_noop");
   grpc_pid_controller pid;
-  grpc_pid_controller_init(&pid, 1, 1, 1);
+  grpc_pid_controller_init(
+      &pid, (grpc_pid_controller_args){.gain_p = 1,
+                                       .gain_i = 1,
+                                       .gain_d = 1,
+                                       .initial_control_value = 1,
+                                       .min_control_value = DBL_MIN,
+                                       .max_control_value = DBL_MAX,
+                                       .integral_range = DBL_MAX});
 }
 
 static void test_simple_convergence(double gain_p, double gain_i, double gain_d,
@@ -55,16 +63,24 @@ static void test_simple_convergence(double gain_p, double gain_i, double gain_d,
           "start=%lf",
           gain_p, gain_i, gain_d, dt, set_point, start);
   grpc_pid_controller pid;
-  grpc_pid_controller_init(&pid, 0.2, 0.1, 0.1);
+  grpc_pid_controller_init(
+      &pid, (grpc_pid_controller_args){.gain_p = gain_p,
+                                       .gain_i = gain_i,
+                                       .gain_d = gain_d,
+                                       .initial_control_value = start,
+                                       .min_control_value = DBL_MIN,
+                                       .max_control_value = DBL_MAX,
+                                       .integral_range = DBL_MAX});
 
-  double current = start;
-
-  for (int i = 0; i < 1000; i++) {
-    current += grpc_pid_controller_update(&pid, set_point - current, 1);
+  for (int i = 0; i < 100000; i++) {
+    grpc_pid_controller_update(&pid, set_point - grpc_pid_controller_last(&pid),
+                               1);
   }
 
-  GPR_ASSERT(fabs(set_point - current) < 0.1);
-  GPR_ASSERT(fabs(pid.error_integral) < 0.1);
+  GPR_ASSERT(fabs(set_point - grpc_pid_controller_last(&pid)) < 0.1);
+  if (gain_i > 0) {
+    GPR_ASSERT(fabs(pid.error_integral) < 0.1);
+  }
 }
 
 int main(int argc, char **argv) {
diff --git a/test/core/util/passthru_endpoint.c b/test/core/util/passthru_endpoint.c
index 4ff93005d7..1e82c737c6 100644
--- a/test/core/util/passthru_endpoint.c
+++ b/test/core/util/passthru_endpoint.c
@@ -152,7 +152,9 @@ static void me_destroy(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep) {
 }
 
 static char *me_get_peer(grpc_endpoint *ep) {
-  return gpr_strdup("fake:mock_endpoint");
+  passthru_endpoint *p = ((half *)ep)->parent;
+  return ((half *)ep) == &p->client ? gpr_strdup("fake:mock_client_endpoint")
+                                    : gpr_strdup("fake:mock_server_endpoint");
 }
 
 static int me_get_fd(grpc_endpoint *ep) { return -1; }
diff --git a/test/cpp/performance/writes_per_rpc_test.cc b/test/cpp/performance/writes_per_rpc_test.cc
new file mode 100644
index 0000000000..7a914c1547
--- /dev/null
+++ b/test/cpp/performance/writes_per_rpc_test.cc
@@ -0,0 +1,268 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc++/channel.h>
+#include <grpc++/create_channel.h>
+#include <grpc++/impl/grpc_library.h>
+#include <grpc++/security/credentials.h>
+#include <grpc++/security/server_credentials.h>
+#include <grpc++/server.h>
+#include <grpc++/server_builder.h>
+#include <grpc/support/log.h>
+#include <gtest/gtest.h>
+
+extern "C" {
+#include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/iomgr/endpoint.h"
+#include "src/core/lib/iomgr/endpoint_pair.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
+#include "src/core/lib/iomgr/tcp_posix.h"
+#include "src/core/lib/surface/channel.h"
+#include "src/core/lib/surface/completion_queue.h"
+#include "src/core/lib/surface/server.h"
+#include "test/core/util/passthru_endpoint.h"
+#include "test/core/util/port.h"
+}
+#include "src/cpp/client/create_channel_internal.h"
+#include "src/proto/grpc/testing/echo.grpc.pb.h"
+#include "test/core/util/test_config.h"
+
+namespace grpc {
+namespace testing {
+
+static void* tag(intptr_t x) { return reinterpret_cast<void*>(x); }
+
+static void ApplyCommonServerBuilderConfig(ServerBuilder* b) {
+  b->SetMaxReceiveMessageSize(INT_MAX);
+  b->SetMaxSendMessageSize(INT_MAX);
+}
+
+static void ApplyCommonChannelArguments(ChannelArguments* c) {
+  c->SetInt(GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH, INT_MAX);
+  c->SetInt(GRPC_ARG_MAX_SEND_MESSAGE_LENGTH, INT_MAX);
+}
+
+static class InitializeStuff {
+ public:
+  InitializeStuff() {
+    init_lib_.init();
+    rq_ = grpc_resource_quota_create("bm");
+  }
+
+  ~InitializeStuff() { init_lib_.shutdown(); }
+
+  grpc_resource_quota* rq() { return rq_; }
+
+ private:
+  internal::GrpcLibrary init_lib_;
+  grpc_resource_quota* rq_;
+} initialize_stuff;
+
+class EndpointPairFixture {
+ public:
+  EndpointPairFixture(Service* service, grpc_endpoint_pair endpoints) {
+    ServerBuilder b;
+    cq_ = b.AddCompletionQueue(true);
+    b.RegisterService(service);
+    ApplyCommonServerBuilderConfig(&b);
+    server_ = b.BuildAndStart();
+
+    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+
+    /* add server endpoint to server_ */
+    {
+      const grpc_channel_args* server_args =
+          grpc_server_get_channel_args(server_->c_server());
+      grpc_transport* transport = grpc_create_chttp2_transport(
+          &exec_ctx, server_args, endpoints.server, 0 /* is_client */);
+
+      grpc_pollset** pollsets;
+      size_t num_pollsets = 0;
+      grpc_server_get_pollsets(server_->c_server(), &pollsets, &num_pollsets);
+
+      for (size_t i = 0; i < num_pollsets; i++) {
+        grpc_endpoint_add_to_pollset(&exec_ctx, endpoints.server, pollsets[i]);
+      }
+
+      grpc_server_setup_transport(&exec_ctx, server_->c_server(), transport,
+                                  NULL, server_args);
+      grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL);
+    }
+
+    /* create channel */
+    {
+      ChannelArguments args;
+      args.SetString(GRPC_ARG_DEFAULT_AUTHORITY, "test.authority");
+      ApplyCommonChannelArguments(&args);
+
+      grpc_channel_args c_args = args.c_channel_args();
+      grpc_transport* transport =
+          grpc_create_chttp2_transport(&exec_ctx, &c_args, endpoints.client, 1);
+      GPR_ASSERT(transport);
+      grpc_channel* channel = grpc_channel_create(
+          &exec_ctx, "target", &c_args, GRPC_CLIENT_DIRECT_CHANNEL, transport);
+      grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL);
+
+      channel_ = CreateChannelInternal("", channel);
+    }
+
+    grpc_exec_ctx_finish(&exec_ctx);
+  }
+
+  virtual ~EndpointPairFixture() {
+    server_->Shutdown();
+    cq_->Shutdown();
+    void* tag;
+    bool ok;
+    while (cq_->Next(&tag, &ok)) {
+    }
+  }
+
+  ServerCompletionQueue* cq() { return cq_.get(); }
+  std::shared_ptr<Channel> channel() { return channel_; }
+
+ private:
+  std::unique_ptr<Server> server_;
+  std::unique_ptr<ServerCompletionQueue> cq_;
+  std::shared_ptr<Channel> channel_;
+};
+
+class InProcessCHTTP2 : public EndpointPairFixture {
+ public:
+  InProcessCHTTP2(Service* service)
+      : EndpointPairFixture(service, MakeEndpoints()) {}
+
+  int writes_performed() const { return stats_.num_writes; }
+
+ private:
+  grpc_passthru_endpoint_stats stats_;
+
+  grpc_endpoint_pair MakeEndpoints() {
+    grpc_endpoint_pair p;
+    grpc_passthru_endpoint_create(&p.client, &p.server, initialize_stuff.rq(),
+                                  &stats_);
+    return p;
+  }
+};
+
+static double UnaryPingPong(int request_size, int response_size) {
+  const int kIterations = 10000;
+
+  EchoTestService::AsyncService service;
+  std::unique_ptr<InProcessCHTTP2> fixture(new InProcessCHTTP2(&service));
+  EchoRequest send_request;
+  EchoResponse send_response;
+  EchoResponse recv_response;
+  if (request_size > 0) {
+    send_request.set_message(std::string(request_size, 'a'));
+  }
+  if (response_size > 0) {
+    send_response.set_message(std::string(response_size, 'a'));
+  }
+  Status recv_status;
+  struct ServerEnv {
+    ServerContext ctx;
+    EchoRequest recv_request;
+    grpc::ServerAsyncResponseWriter<EchoResponse> response_writer;
+    ServerEnv() : response_writer(&ctx) {}
+  };
+  uint8_t server_env_buffer[2 * sizeof(ServerEnv)];
+  ServerEnv* server_env[2] = {
+      reinterpret_cast<ServerEnv*>(server_env_buffer),
+      reinterpret_cast<ServerEnv*>(server_env_buffer + sizeof(ServerEnv))};
+  new (server_env[0]) ServerEnv;
+  new (server_env[1]) ServerEnv;
+  service.RequestEcho(&server_env[0]->ctx, &server_env[0]->recv_request,
+                      &server_env[0]->response_writer, fixture->cq(),
+                      fixture->cq(), tag(0));
+  service.RequestEcho(&server_env[1]->ctx, &server_env[1]->recv_request,
+                      &server_env[1]->response_writer, fixture->cq(),
+                      fixture->cq(), tag(1));
+  std::unique_ptr<EchoTestService::Stub> stub(
+      EchoTestService::NewStub(fixture->channel()));
+  for (int iteration = 0; iteration < kIterations; iteration++) {
+    recv_response.Clear();
+    ClientContext cli_ctx;
+    std::unique_ptr<ClientAsyncResponseReader<EchoResponse>> response_reader(
+        stub->AsyncEcho(&cli_ctx, send_request, fixture->cq()));
+    void* t;
+    bool ok;
+    GPR_ASSERT(fixture->cq()->Next(&t, &ok));
+    GPR_ASSERT(ok);
+    GPR_ASSERT(t == tag(0) || t == tag(1));
+    intptr_t slot = reinterpret_cast<intptr_t>(t);
+    ServerEnv* senv = server_env[slot];
+    senv->response_writer.Finish(send_response, Status::OK, tag(3));
+    response_reader->Finish(&recv_response, &recv_status, tag(4));
+    for (int i = (1 << 3) | (1 << 4); i != 0;) {
+      GPR_ASSERT(fixture->cq()->Next(&t, &ok));
+      GPR_ASSERT(ok);
+      int tagnum = (int)reinterpret_cast<intptr_t>(t);
+      GPR_ASSERT(i & (1 << tagnum));
+      i -= 1 << tagnum;
+    }
+    GPR_ASSERT(recv_status.ok());
+
+    senv->~ServerEnv();
+    senv = new (senv) ServerEnv();
+    service.RequestEcho(&senv->ctx, &senv->recv_request, &senv->response_writer,
+                        fixture->cq(), fixture->cq(), tag(slot));
+  }
+
+  double writes_per_iteration =
+      (double)fixture->writes_performed() / (double)kIterations;
+
+  fixture.reset();
+  server_env[0]->~ServerEnv();
+  server_env[1]->~ServerEnv();
+
+  return writes_per_iteration;
+}
+
+TEST(WritesPerRpcTest, UnaryPingPong) {
+  EXPECT_LT(UnaryPingPong(0, 0), 2.05);
+  EXPECT_LT(UnaryPingPong(1, 0), 2.05);
+  EXPECT_LT(UnaryPingPong(0, 1), 2.05);
+  EXPECT_LT(UnaryPingPong(4096, 0), 2.2);
+  EXPECT_LT(UnaryPingPong(0, 4096), 2.2);
+}
+
+}  // 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_sync.cc b/test/cpp/qps/client_sync.cc
index b1e61865e7..498416c64a 100644
--- a/test/cpp/qps/client_sync.cc
+++ b/test/cpp/qps/client_sync.cc
@@ -153,7 +153,6 @@ class SynchronousStreamingClient final : public SynchronousClient {
       if (*stream) {
         (*stream)->WritesDone();
         Status s = (*stream)->Finish();
-        EXPECT_TRUE(s.ok());
         if (!s.ok()) {
           gpr_log(GPR_ERROR, "Stream %zu received an error %s", i,
                   s.error_message().c_str());
@@ -173,7 +172,11 @@ class SynchronousStreamingClient final : public SynchronousClient {
       entry->set_value((UsageTimer::Now() - start) * 1e9);
       return true;
     }
-    return false;
+    auto* stub = channels_[thread_idx % channels_.size()].get_stub();
+    context_[thread_idx].~ClientContext();
+    new (&context_[thread_idx]) ClientContext();
+    stream_[thread_idx] = stub->StreamingCall(&context_[thread_idx]);
+    return true;
   }
 
  private:
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index 8382695f66..285b7dd321 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -1301,6 +1301,8 @@ src/core/lib/surface/validate_metadata.c \
 src/core/lib/surface/validate_metadata.h \
 src/core/lib/surface/version.c \
 src/core/lib/transport/README.md \
+src/core/lib/transport/bdp_estimator.c \
+src/core/lib/transport/bdp_estimator.h \
 src/core/lib/transport/byte_stream.c \
 src/core/lib/transport/byte_stream.h \
 src/core/lib/transport/connectivity_state.c \
diff --git a/tools/run_tests/generated/sources_and_headers.json b/tools/run_tests/generated/sources_and_headers.json
index 8a9bedc94f..52d8ae183b 100644
--- a/tools/run_tests/generated/sources_and_headers.json
+++ b/tools/run_tests/generated/sources_and_headers.json
@@ -104,6 +104,23 @@
   }, 
   {
     "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "is_filegroup": false, 
+    "language": "c", 
+    "name": "bdp_estimator_test", 
+    "src": [
+      "test/core/transport/bdp_estimator_test.c"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
+  {
+    "deps": [
       "grpc", 
       "grpc_test_util"
     ], 
@@ -3447,6 +3464,25 @@
   {
     "deps": [
       "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc++", 
+      "grpc++_test_util", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "is_filegroup": false, 
+    "language": "c++", 
+    "name": "writes_per_rpc_test", 
+    "src": [
+      "test/cpp/performance/writes_per_rpc_test.cc"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
+  {
+    "deps": [
+      "gpr", 
       "grpc"
     ], 
     "headers": [], 
@@ -7096,6 +7132,7 @@
       "src/core/lib/surface/lame_client.h", 
       "src/core/lib/surface/server.h", 
       "src/core/lib/surface/validate_metadata.h", 
+      "src/core/lib/transport/bdp_estimator.h", 
       "src/core/lib/transport/byte_stream.h", 
       "src/core/lib/transport/connectivity_state.h", 
       "src/core/lib/transport/error_utils.h", 
@@ -7320,6 +7357,8 @@
       "src/core/lib/surface/validate_metadata.c", 
       "src/core/lib/surface/validate_metadata.h", 
       "src/core/lib/surface/version.c", 
+      "src/core/lib/transport/bdp_estimator.c", 
+      "src/core/lib/transport/bdp_estimator.h", 
       "src/core/lib/transport/byte_stream.c", 
       "src/core/lib/transport/byte_stream.h", 
       "src/core/lib/transport/connectivity_state.c", 
diff --git a/tools/run_tests/generated/tests.json b/tools/run_tests/generated/tests.json
index 972f61561f..4cc543962e 100644
--- a/tools/run_tests/generated/tests.json
+++ b/tools/run_tests/generated/tests.json
@@ -127,6 +127,28 @@
     "flaky": false, 
     "gtest": false, 
     "language": "c", 
+    "name": "bdp_estimator_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, 
+    "language": "c", 
     "name": "bin_decoder_test", 
     "platforms": [
       "linux", 
@@ -2430,7 +2452,9 @@
     ]
   }, 
   {
-    "args": [], 
+    "args": [
+      "--benchmark_min_time=0"
+    ], 
     "ci_platforms": [
       "linux", 
       "mac", 
@@ -3212,6 +3236,26 @@
     "ci_platforms": [
       "linux", 
       "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 0.5, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "gtest": true, 
+    "language": "c++", 
+    "name": "writes_per_rpc_test", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [], 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
       "posix", 
       "windows"
     ], 
diff --git a/vsprojects/buildtests_c.sln b/vsprojects/buildtests_c.sln
index aa382154eb..ca7f969aa1 100644
--- a/vsprojects/buildtests_c.sln
+++ b/vsprojects/buildtests_c.sln
@@ -80,6 +80,17 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "badreq_bad_client_test", "v
 		{B23D3D1A-9438-4EDA-BEB6-9A0A03D17792} = {B23D3D1A-9438-4EDA-BEB6-9A0A03D17792}
 	EndProjectSection
 EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "bdp_estimator_test", "vcxproj\test\bdp_estimator_test\bdp_estimator_test.vcxproj", "{56314C05-7748-B7FD-F9DE-F975A0275427}"
+	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}") = "bin_decoder_test", "vcxproj\test\bin_decoder_test\bin_decoder_test.vcxproj", "{6BFAC6BA-3B9D-E8F5-BE35-91E8EFB9E25B}"
 	ProjectSection(myProperties) = preProject
         	lib = "False"
@@ -1703,6 +1714,22 @@ Global
 		{8A811C28-E04E-A444-E4C1-7588DF5B90AE}.Release-DLL|Win32.Build.0 = Release|Win32
 		{8A811C28-E04E-A444-E4C1-7588DF5B90AE}.Release-DLL|x64.ActiveCfg = Release|x64
 		{8A811C28-E04E-A444-E4C1-7588DF5B90AE}.Release-DLL|x64.Build.0 = Release|x64
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Debug|Win32.ActiveCfg = Debug|Win32
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Debug|x64.ActiveCfg = Debug|x64
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Release|Win32.ActiveCfg = Release|Win32
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Release|x64.ActiveCfg = Release|x64
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Debug|Win32.Build.0 = Debug|Win32
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Debug|x64.Build.0 = Debug|x64
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Release|Win32.Build.0 = Release|Win32
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Release|x64.Build.0 = Release|x64
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Debug-DLL|Win32.ActiveCfg = Debug|Win32
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Debug-DLL|Win32.Build.0 = Debug|Win32
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Debug-DLL|x64.ActiveCfg = Debug|x64
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Debug-DLL|x64.Build.0 = Debug|x64
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Release-DLL|Win32.ActiveCfg = Release|Win32
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Release-DLL|Win32.Build.0 = Release|Win32
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Release-DLL|x64.ActiveCfg = Release|x64
+		{56314C05-7748-B7FD-F9DE-F975A0275427}.Release-DLL|x64.Build.0 = Release|x64
 		{6BFAC6BA-3B9D-E8F5-BE35-91E8EFB9E25B}.Debug|Win32.ActiveCfg = Debug|Win32
 		{6BFAC6BA-3B9D-E8F5-BE35-91E8EFB9E25B}.Debug|x64.ActiveCfg = Debug|x64
 		{6BFAC6BA-3B9D-E8F5-BE35-91E8EFB9E25B}.Release|Win32.ActiveCfg = Release|Win32
diff --git a/vsprojects/vcxproj/grpc/grpc.vcxproj b/vsprojects/vcxproj/grpc/grpc.vcxproj
index 13d825af68..c7aa771e5f 100644
--- a/vsprojects/vcxproj/grpc/grpc.vcxproj
+++ b/vsprojects/vcxproj/grpc/grpc.vcxproj
@@ -391,6 +391,7 @@
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\surface\lame_client.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\surface\server.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\surface\validate_metadata.h" />
+    <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\bdp_estimator.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\byte_stream.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\connectivity_state.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\error_utils.h" />
@@ -701,6 +702,8 @@
     </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\surface\version.c">
     </ClCompile>
+    <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\bdp_estimator.c">
+    </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\byte_stream.c">
     </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\connectivity_state.c">
diff --git a/vsprojects/vcxproj/grpc/grpc.vcxproj.filters b/vsprojects/vcxproj/grpc/grpc.vcxproj.filters
index de2e82173f..00aa8b2781 100644
--- a/vsprojects/vcxproj/grpc/grpc.vcxproj.filters
+++ b/vsprojects/vcxproj/grpc/grpc.vcxproj.filters
@@ -319,6 +319,9 @@
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\surface\version.c">
       <Filter>src\core\lib\surface</Filter>
     </ClCompile>
+    <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\bdp_estimator.c">
+      <Filter>src\core\lib\transport</Filter>
+    </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\byte_stream.c">
       <Filter>src\core\lib\transport</Filter>
     </ClCompile>
@@ -1037,6 +1040,9 @@
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\surface\validate_metadata.h">
       <Filter>src\core\lib\surface</Filter>
     </ClInclude>
+    <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\bdp_estimator.h">
+      <Filter>src\core\lib\transport</Filter>
+    </ClInclude>
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\byte_stream.h">
       <Filter>src\core\lib\transport</Filter>
     </ClInclude>
diff --git a/vsprojects/vcxproj/grpc_test_util/grpc_test_util.vcxproj b/vsprojects/vcxproj/grpc_test_util/grpc_test_util.vcxproj
index 98f73b76bf..57cbb2c496 100644
--- a/vsprojects/vcxproj/grpc_test_util/grpc_test_util.vcxproj
+++ b/vsprojects/vcxproj/grpc_test_util/grpc_test_util.vcxproj
@@ -285,6 +285,7 @@
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\surface\lame_client.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\surface\server.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\surface\validate_metadata.h" />
+    <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\bdp_estimator.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\byte_stream.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\connectivity_state.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\error_utils.h" />
@@ -552,6 +553,8 @@
     </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\surface\version.c">
     </ClCompile>
+    <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\bdp_estimator.c">
+    </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\byte_stream.c">
     </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\connectivity_state.c">
diff --git a/vsprojects/vcxproj/grpc_test_util/grpc_test_util.vcxproj.filters b/vsprojects/vcxproj/grpc_test_util/grpc_test_util.vcxproj.filters
index d88585d002..620649a06c 100644
--- a/vsprojects/vcxproj/grpc_test_util/grpc_test_util.vcxproj.filters
+++ b/vsprojects/vcxproj/grpc_test_util/grpc_test_util.vcxproj.filters
@@ -379,6 +379,9 @@
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\surface\version.c">
       <Filter>src\core\lib\surface</Filter>
     </ClCompile>
+    <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\bdp_estimator.c">
+      <Filter>src\core\lib\transport</Filter>
+    </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\byte_stream.c">
       <Filter>src\core\lib\transport</Filter>
     </ClCompile>
@@ -827,6 +830,9 @@
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\surface\validate_metadata.h">
       <Filter>src\core\lib\surface</Filter>
     </ClInclude>
+    <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\bdp_estimator.h">
+      <Filter>src\core\lib\transport</Filter>
+    </ClInclude>
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\byte_stream.h">
       <Filter>src\core\lib\transport</Filter>
     </ClInclude>
diff --git a/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj b/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj
index 826c06576e..f2c9d1ae03 100644
--- a/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj
+++ b/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj
@@ -381,6 +381,7 @@
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\surface\lame_client.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\surface\server.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\surface\validate_metadata.h" />
+    <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\bdp_estimator.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\byte_stream.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\connectivity_state.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\error_utils.h" />
@@ -669,6 +670,8 @@
     </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\surface\version.c">
     </ClCompile>
+    <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\bdp_estimator.c">
+    </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\byte_stream.c">
     </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\connectivity_state.c">
diff --git a/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters b/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters
index 06ddac9de7..d3117bd272 100644
--- a/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters
+++ b/vsprojects/vcxproj/grpc_unsecure/grpc_unsecure.vcxproj.filters
@@ -322,6 +322,9 @@
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\surface\version.c">
       <Filter>src\core\lib\surface</Filter>
     </ClCompile>
+    <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\bdp_estimator.c">
+      <Filter>src\core\lib\transport</Filter>
+    </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\lib\transport\byte_stream.c">
       <Filter>src\core\lib\transport</Filter>
     </ClCompile>
@@ -950,6 +953,9 @@
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\surface\validate_metadata.h">
       <Filter>src\core\lib\surface</Filter>
     </ClInclude>
+    <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\bdp_estimator.h">
+      <Filter>src\core\lib\transport</Filter>
+    </ClInclude>
     <ClInclude Include="$(SolutionDir)\..\src\core\lib\transport\byte_stream.h">
       <Filter>src\core\lib\transport</Filter>
     </ClInclude>
diff --git a/vsprojects/vcxproj/test/bdp_estimator_test/bdp_estimator_test.vcxproj b/vsprojects/vcxproj/test/bdp_estimator_test/bdp_estimator_test.vcxproj
new file mode 100644
index 0000000000..e37d7b9848
--- /dev/null
+++ b/vsprojects/vcxproj/test/bdp_estimator_test/bdp_estimator_test.vcxproj
@@ -0,0 +1,199 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="12.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.1.0.204.1\build\native\grpc.dependencies.openssl.props" Condition="Exists('$(SolutionDir)\..\vsprojects\packages\grpc.dependencies.openssl.1.0.204.1\build\native\1.0.204.1.props')" />
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{56314C05-7748-B7FD-F9DE-F975A0275427}</ProjectGuid>
+    <IgnoreWarnIntDirInTempDetected>true</IgnoreWarnIntDirInTempDetected>
+    <IntDir>$(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'">
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diff --git a/vsprojects/vcxproj/test/bdp_estimator_test/bdp_estimator_test.vcxproj.filters b/vsprojects/vcxproj/test/bdp_estimator_test/bdp_estimator_test.vcxproj.filters
new file mode 100644
index 0000000000..e45ccf8444
--- /dev/null
+++ b/vsprojects/vcxproj/test/bdp_estimator_test/bdp_estimator_test.vcxproj.filters
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