[chttp2] Use experiments framework for peer_state_based_framing (#30853)

* [chttp2] Use experiments framework for peer_state_based_framing

* Automated change: Fix sanity tests

Co-authored-by: ctiller <ctiller@users.noreply.github.com>

BUILD

@@ -6746,6 +6746,7 @@ grpc_cc_library(
         "bitset",
         "chttp2_flow_control",
         "debug_location",
+        "experiments",
         "gpr",
         "grpc_base",
         "grpc_codegen",

bazel/experiments.bzl

@@ -24,6 +24,7 @@ EXPERIMENTS = {
     ],
     "flow_control_test": [
         "flow_control_fixes",
+        "peer_state_based_framing",
         "tcp_frame_size_tuning",
         "tcp_rcv_lowat",
         "tcp_read_chunks",

src/core/ext/transport/chttp2/transport/chttp2_transport.cc

@@ -60,10 +60,10 @@
 #include "src/core/ext/transport/chttp2/transport/varint.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/debug/stats_data.h"
+#include "src/core/lib/experiments/experiments.h"
 #include "src/core/lib/gpr/useful.h"
 #include "src/core/lib/gprpp/bitset.h"
 #include "src/core/lib/gprpp/debug_location.h"
-#include "src/core/lib/gprpp/global_config_env.h"
 #include "src/core/lib/gprpp/ref_counted.h"
 #include "src/core/lib/gprpp/status_helper.h"
 #include "src/core/lib/gprpp/time.h"
@@ -91,12 +91,6 @@
 #include "src/core/lib/transport/transport.h"
 #include "src/core/lib/transport/transport_impl.h"
 
-GPR_GLOBAL_CONFIG_DEFINE_BOOL(
-    grpc_experimental_enable_peer_state_based_framing, false,
-    "If set, the max sizes of frames sent to lower layers is controlled based "
-    "on the peer's memory pressure which is reflected in its max http2 frame "
-    "size.");
-
 #define DEFAULT_CONNECTION_WINDOW_TARGET (1024 * 1024)
 #define MAX_WINDOW 0x7fffffffu
 #define MAX_WRITE_BUFFER_SIZE (64 * 1024 * 1024)
@@ -878,18 +872,16 @@ static void write_action_begin_locked(void* gt,
 }
 
 static void write_action(void* gt, grpc_error_handle /*error*/) {
-  static bool kEnablePeerStateBasedFraming =
-      GPR_GLOBAL_CONFIG_GET(grpc_experimental_enable_peer_state_based_framing);
   grpc_chttp2_transport* t = static_cast<grpc_chttp2_transport*>(gt);
   void* cl = t->cl;
   t->cl = nullptr;
-  // If grpc_experimental_enable_peer_state_based_framing is set to true,
+  // If the peer_state_based_framing experiment is set to true,
   // choose max_frame_size as 2 * max http2 frame size of peer. If peer is under
   // high memory pressure, then it would advertise a smaller max http2 frame
   // size. With this logic, the sender would automatically reduce the sending
   // frame size as well.
   int max_frame_size =
-      kEnablePeerStateBasedFraming
+      grpc_core::IsPeerStateBasedFramingEnabled()
           ? 2 * t->settings[GRPC_PEER_SETTINGS]
                            [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE]
           : INT_MAX;

src/core/lib/experiments/experiments.cc

@@ -29,6 +29,10 @@ const char* const description_tcp_read_chunks =
     "malloc to recycle arbitrary large blocks.";
 const char* const description_tcp_rcv_lowat =
     "Use SO_RCVLOWAT to avoid wakeups on the read path.";
+const char* const description_peer_state_based_framing =
+    "If set, the max sizes of frames sent to lower layers is controlled based "
+    "on the peer's memory pressure which is reflected in its max http2 frame "
+    "size.";
 const char* const description_flow_control_fixes =
     "Various fixes for flow control, max frame size setting.";
 const char* const description_memory_pressure_controller =
@@ -45,6 +49,7 @@ const ExperimentMetadata g_experiment_metadata[] = {
     {"tcp_frame_size_tuning", description_tcp_frame_size_tuning, false},
     {"tcp_read_chunks", description_tcp_read_chunks, false},
     {"tcp_rcv_lowat", description_tcp_rcv_lowat, false},
+    {"peer_state_based_framing", description_peer_state_based_framing, false},
     {"flow_control_fixes", description_flow_control_fixes, false},
     {"memory_pressure_controller", description_memory_pressure_controller,
      false},

src/core/lib/experiments/experiments.h

@@ -28,15 +28,16 @@ namespace grpc_core {
 inline bool IsTcpFrameSizeTuningEnabled() { return IsExperimentEnabled(0); }
 inline bool IsTcpReadChunksEnabled() { return IsExperimentEnabled(1); }
 inline bool IsTcpRcvLowatEnabled() { return IsExperimentEnabled(2); }
-inline bool IsFlowControlFixesEnabled() { return IsExperimentEnabled(3); }
+inline bool IsPeerStateBasedFramingEnabled() { return IsExperimentEnabled(3); }
+inline bool IsFlowControlFixesEnabled() { return IsExperimentEnabled(4); }
 inline bool IsMemoryPressureControllerEnabled() {
-  return IsExperimentEnabled(4);
+  return IsExperimentEnabled(5);
 }
 inline bool IsPeriodicResourceQuotaReclamationEnabled() {
-  return IsExperimentEnabled(5);
+  return IsExperimentEnabled(6);
 }
 inline bool IsUnconstrainedMaxQuotaBufferSizeEnabled() {
-  return IsExperimentEnabled(6);
+  return IsExperimentEnabled(7);
 }
 
 struct ExperimentMetadata {
@@ -45,7 +46,7 @@ struct ExperimentMetadata {
   bool default_value;
 };
 
-constexpr const size_t kNumExperiments = 7;
+constexpr const size_t kNumExperiments = 8;
 extern const ExperimentMetadata g_experiment_metadata[kNumExperiments];
 
 }  // namespace grpc_core

src/core/lib/experiments/experiments.yaml

@@ -51,6 +51,15 @@
   expiry: 2022/10/01
   owner: ctiller@google.com
   test_tags: ["endpoint_test", "flow_control_test"]
+- name: peer_state_based_framing
+  description:
+    If set, the max sizes of frames sent to lower layers is controlled based
+    on the peer's memory pressure which is reflected in its max http2 frame
+    size.
+  default: false
+  expiry: 2022/11/01
+  owner: vigneshbabu@google.com
+  test_tags: ["flow_control_test"]
 - name: flow_control_fixes
   description:
     Various fixes for flow control, max frame size setting.