Merge pull request #9926 from y-zeng/retry_pings

Retry sending pings if they are delayed

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

@@ -148,6 +148,8 @@ 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);
+static void retry_initiate_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
+                                       grpc_error *error);
 
 #define DEFAULT_MIN_TIME_BETWEEN_PINGS_MS 0
 #define DEFAULT_MAX_PINGS_BETWEEN_DATA 3
@@ -273,6 +275,8 @@ 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->retry_initiate_ping_locked, retry_initiate_ping_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,
@@ -482,6 +486,7 @@ 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;
+  t->ping_state.is_delayed_ping_timer_set = false;
 
   /** Start client-side keepalive pings */
   if (t->is_client) {
@@ -1407,6 +1412,13 @@ static void send_ping_locked(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   }
 }
 
+static void retry_initiate_ping_locked(grpc_exec_ctx *exec_ctx, void *tp,
+                                       grpc_error *error) {
+  grpc_chttp2_transport *t = tp;
+  t->ping_state.is_delayed_ping_timer_set = false;
+  grpc_chttp2_initiate_write(exec_ctx, t, false, "retry_send_ping");
+}
+
 void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                           uint64_t id) {
   grpc_chttp2_ping_queue *pq =
@@ -2185,9 +2197,7 @@ static void finish_keepalive_ping_locked(grpc_exec_ctx *exec_ctx, void *arg,
       grpc_timer_init(
           exec_ctx, &t->keepalive_ping_timer,
           gpr_time_add(gpr_now(GPR_CLOCK_MONOTONIC), t->keepalive_time),
-          grpc_closure_create(init_keepalive_ping_locked, t,
-                              grpc_combiner_scheduler(t->combiner, false)),
-          gpr_now(GPR_CLOCK_MONOTONIC));
+          &t->init_keepalive_ping_locked, gpr_now(GPR_CLOCK_MONOTONIC));
     }
   }
   GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "keepalive ping end");

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

@@ -102,6 +102,8 @@ typedef struct {
 typedef struct {
   gpr_timespec last_ping_sent_time;
   int pings_before_data_required;
+  grpc_timer delayed_ping_timer;
+  bool is_delayed_ping_timer_set;
 } grpc_chttp2_repeated_ping_state;
 
 /* deframer state for the overall http2 stream of bytes */
@@ -308,6 +310,7 @@ struct grpc_chttp2_transport {
   grpc_chttp2_repeated_ping_policy ping_policy;
   grpc_chttp2_repeated_ping_state ping_state;
   uint64_t ping_ctr; /* unique id for pings */
+  grpc_closure retry_initiate_ping_locked;
 
   /** ping acks */
   size_t ping_ack_count;

src/core/ext/transport/chttp2/transport/writing.c

@@ -101,6 +101,14 @@ static void maybe_initiate_ping(grpc_exec_ctx *exec_ctx,
               "Ping delayed [%p]: not enough time elapsed since last ping",
               t->peer_string);
     }
+    if (!t->ping_state.is_delayed_ping_timer_set) {
+      t->ping_state.is_delayed_ping_timer_set = true;
+      grpc_timer_init(exec_ctx, &t->ping_state.delayed_ping_timer,
+                      gpr_time_add(t->ping_state.last_ping_sent_time,
+                                   t->ping_policy.min_time_between_pings),
+                      &t->retry_initiate_ping_locked,
+                      gpr_now(GPR_CLOCK_MONOTONIC));
+    }
     return;
   }
   /* coalesce equivalent pings into this one */

test/core/end2end/tests/ping.c

@@ -41,9 +41,12 @@
 
 #include "test/core/end2end/cq_verifier.h"
 
+#define PING_NUM 5
+
 static void *tag(intptr_t t) { return (void *)t; }
 
-static void test_ping(grpc_end2end_test_config config) {
+static void test_ping(grpc_end2end_test_config config,
+                      int min_time_between_pings_ms) {
   grpc_end2end_test_fixture f = config.create_fixture(NULL, NULL);
   cq_verifier *cqv = cq_verifier_create(f.cq);
   grpc_connectivity_state state = GRPC_CHANNEL_IDLE;
@@ -51,7 +54,7 @@ static void test_ping(grpc_end2end_test_config config) {
 
   grpc_arg a[] = {{.type = GRPC_ARG_INTEGER,
                    .key = GRPC_ARG_HTTP2_MIN_TIME_BETWEEN_PINGS_MS,
-                   .value.integer = 0},
+                   .value.integer = min_time_between_pings_ms},
                   {.type = GRPC_ARG_INTEGER,
                    .key = GRPC_ARG_HTTP2_MAX_PINGS_WITHOUT_DATA,
                    .value.integer = 20}};
@@ -70,7 +73,11 @@ static void test_ping(grpc_end2end_test_config config) {
      READY is reached */
   while (state != GRPC_CHANNEL_READY) {
     grpc_channel_watch_connectivity_state(
-        f.client, state, grpc_timeout_seconds_to_deadline(3), f.cq, tag(99));
+        f.client, state,
+        gpr_time_add(grpc_timeout_seconds_to_deadline(3),
+                     gpr_time_from_millis(min_time_between_pings_ms * PING_NUM,
+                                          GPR_TIMESPAN)),
+        f.cq, tag(99));
     CQ_EXPECT_COMPLETION(cqv, tag(99), 1);
     cq_verify(cqv);
     state = grpc_channel_check_connectivity_state(f.client, 0);
@@ -79,7 +86,7 @@ static void test_ping(grpc_end2end_test_config config) {
                state == GRPC_CHANNEL_TRANSIENT_FAILURE);
   }
 
-  for (i = 1; i <= 5; i++) {
+  for (i = 1; i <= PING_NUM; i++) {
     grpc_channel_ping(f.client, f.cq, tag(i), NULL);
     CQ_EXPECT_COMPLETION(cqv, tag(i), 1);
     cq_verify(cqv);
@@ -102,7 +109,8 @@ static void test_ping(grpc_end2end_test_config config) {
 
 void ping(grpc_end2end_test_config config) {
   GPR_ASSERT(config.feature_mask & FEATURE_MASK_SUPPORTS_DELAYED_CONNECTION);
-  test_ping(config);
+  test_ping(config, 0);
+  test_ping(config, 100);
 }
 
 void ping_pre_init(void) {}