Initiate HTTP/2 writes on BDP pings too

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

@@ -857,6 +857,9 @@ static void inc_initiate_write_reason(
     case GRPC_CHTTP2_INITIATE_WRITE_APPLICATION_PING:
       GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_APPLICATION_PING();
       break;
+    case GRPC_CHTTP2_INITIATE_WRITE_BDP_PING:
+      GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_BDP_ESTIMATOR_PING();
+      break;
     case GRPC_CHTTP2_INITIATE_WRITE_KEEPALIVE_PING:
       GRPC_STATS_INC_HTTP2_INITIATE_WRITE_DUE_TO_KEEPALIVE_PING();
       break;
@@ -2579,6 +2582,7 @@ void schedule_bdp_ping_locked(grpc_chttp2_transport* t) {
                         grpc_schedule_on_exec_ctx),
       GRPC_CLOSURE_INIT(&t->finish_bdp_ping_locked, finish_bdp_ping, t,
                         grpc_schedule_on_exec_ctx));
+  grpc_chttp2_initiate_write(t, GRPC_CHTTP2_INITIATE_WRITE_BDP_PING);
 }
 
 static void start_bdp_ping(void* tp, grpc_error* error) {
@@ -3260,6 +3264,8 @@ const char* grpc_chttp2_initiate_write_reason_string(
       return "FLOW_CONTROL_UNSTALLED_BY_UPDATE";
     case GRPC_CHTTP2_INITIATE_WRITE_APPLICATION_PING:
       return "APPLICATION_PING";
+    case GRPC_CHTTP2_INITIATE_WRITE_BDP_PING:
+      return "BDP_PING";
     case GRPC_CHTTP2_INITIATE_WRITE_KEEPALIVE_PING:
       return "KEEPALIVE_PING";
     case GRPC_CHTTP2_INITIATE_WRITE_TRANSPORT_FLOW_CONTROL_UNSTALLED:

src/core/ext/transport/chttp2/transport/internal.h

@@ -101,6 +101,7 @@ typedef enum {
   GRPC_CHTTP2_INITIATE_WRITE_FLOW_CONTROL_UNSTALLED_BY_SETTING,
   GRPC_CHTTP2_INITIATE_WRITE_FLOW_CONTROL_UNSTALLED_BY_UPDATE,
   GRPC_CHTTP2_INITIATE_WRITE_APPLICATION_PING,
+  GRPC_CHTTP2_INITIATE_WRITE_BDP_PING,
   GRPC_CHTTP2_INITIATE_WRITE_KEEPALIVE_PING,
   GRPC_CHTTP2_INITIATE_WRITE_TRANSPORT_FLOW_CONTROL_UNSTALLED,
   GRPC_CHTTP2_INITIATE_WRITE_PING_RESPONSE,

test/core/transport/chttp2/too_many_pings_test.cc

@@ -710,6 +710,8 @@ TEST(TooManyPings, BdpPingNotSentWithoutReceiveSideActivity) {
   ASSERT_EQ(grpc_channel_check_connectivity_state(channel, 0),
             GRPC_CHANNEL_READY);
   PerformCallWithResponsePayload(channel, server, cq);
+  // Wait a bit to make sure that the BDP ping goes out.
+  cq_verify_empty_timeout(cqv, 1);
   // The call with a response payload should have triggered a BDP ping.
   // Send two more pings to verify. The second ping should cause a disconnect.
   // If BDP was not sent, the second ping would not cause a disconnect.
@@ -720,6 +722,7 @@ TEST(TooManyPings, BdpPingNotSentWithoutReceiveSideActivity) {
   grpc_channel_ping(channel, cq, tag(4), nullptr);
   CQ_EXPECT_COMPLETION(cqv, tag(4), 1);
   cq_verify(cqv, 5);
+  cq_verify_empty_timeout(cqv, 1);
   ASSERT_NE(grpc_channel_check_connectivity_state(channel, 0),
             GRPC_CHANNEL_READY);
   cq_verifier_destroy(cqv);