Add tracer for pending tags

1 files changed, 31 insertions, 0 deletions

diff --git a/src/core/lib/surface/completion_queue.c b/src/core/lib/surface/completion_queue.c
index 2412f78a06..5654b86d8b 100644
--- a/src/core/lib/surface/completion_queue.c
+++ b/src/core/lib/surface/completion_queue.c
@@ -39,6 +39,7 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/atm.h>
 #include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
 #include <grpc/support/time.h>
 
 #include "src/core/lib/iomgr/pollset.h"
@@ -50,6 +51,9 @@
 #include "src/core/lib/surface/event_string.h"
 
 int grpc_trace_operation_failures;
+#ifndef NDEBUG
+int grpc_trace_pending_tags;
+#endif
 
 typedef struct {
   grpc_pollset_worker **worker;
@@ -338,6 +342,25 @@ static bool cq_is_next_finished(grpc_exec_ctx *exec_ctx, void *arg) {
   return gpr_time_cmp(a->deadline, gpr_now(a->deadline.clock_type)) < 0;
 }
 
+#ifndef NDEBUG
+static void dump_pending_tags(grpc_completion_queue *cc) {
+  if (!grpc_trace_pending_tags) return;
+
+  gpr_strvec v;
+  gpr_strvec_init(&v);
+  gpr_strvec_add(&v, gpr_strdup("PENDING TAGS:"));
+  for (size_t i = 0; i < cc->outstanding_tag_count; i++) {
+    char *s;
+    gpr_asprintf(&s, " %p", cc->outstanding_tags[i]);
+    gpr_strvec_add(&v, s);
+  }
+  char *out = gpr_strvec_flatten(&v, NULL);
+  gpr_strvec_destroy(&v);
+  gpr_log(GPR_DEBUG, "%s", out);
+  gpr_free(out);
+}
+#endif
+
 grpc_event grpc_completion_queue_next(grpc_completion_queue *cc,
                                       gpr_timespec deadline, void *reserved) {
   grpc_event ret;
@@ -357,6 +380,10 @@ grpc_event grpc_completion_queue_next(grpc_completion_queue *cc,
           reserved));
   GPR_ASSERT(!reserved);
 
+#ifndef NDEBUG
+  dump_pending_tags(cc);
+#endif
+
   deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
 
   cq_is_finished_arg is_finished_arg = {cc, deadline, NULL, NULL};
@@ -510,6 +537,10 @@ grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,
   }
   GPR_ASSERT(!reserved);
 
+#ifndef NDEBUG
+  dump_pending_tags(cc);
+#endif
+
   deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
 
   cq_is_finished_arg is_finished_arg = {cc, deadline, NULL, tag};