Add chttp2 trace

src/core/ext/transport/chttp2/transport/chttp2_plugin.c

@@ -23,6 +23,9 @@
 void grpc_chttp2_plugin_init(void) {
   grpc_register_tracer("http", &grpc_http_trace);
   grpc_register_tracer("flowctl", &grpc_flowctl_trace);
+#ifndef NDEBUG
+  grpc_register_tracer("chttp2_refcount", &grpc_trace_chttp2_refcount);
+#endif
 }
 
 void grpc_chttp2_plugin_shutdown(void) {}

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

@@ -76,6 +76,10 @@ static bool g_default_keepalive_permit_without_calls =
 grpc_tracer_flag grpc_http_trace = GRPC_TRACER_INITIALIZER(false);
 grpc_tracer_flag grpc_flowctl_trace = GRPC_TRACER_INITIALIZER(false);
 
+#ifndef NDEBUG
+grpc_tracer_flag grpc_trace_chttp2_refcount = GRPC_TRACER_INITIALIZER(false);
+#endif
+
 static const grpc_transport_vtable vtable;
 
 /* forward declarations of various callbacks that we'll build closures around */
@@ -212,20 +216,26 @@ static void destruct_transport(grpc_exec_ctx *exec_ctx,
   gpr_free(t);
 }
 
-#ifdef GRPC_CHTTP2_REFCOUNTING_DEBUG
+#ifndef NDEBUG
 void grpc_chttp2_unref_transport(grpc_exec_ctx *exec_ctx,
                                  grpc_chttp2_transport *t, const char *reason,
                                  const char *file, int line) {
-  gpr_log(GPR_DEBUG, "chttp2:unref:%p %" PRIdPTR "->%" PRIdPTR " %s [%s:%d]", t,
-          t->refs.count, t->refs.count - 1, reason, file, line);
+  if (GRPC_TRACER_ON(grpc_trace_chttp2_refcount)) {
+    gpr_atm val = gpr_atm_no_barrier_load(&t->refs.count);
+    gpr_log(GPR_DEBUG, "chttp2:unref:%p %" PRIdPTR "->%" PRIdPTR " %s [%s:%d]",
+            t, val, val - 1, reason, file, line);
+  }
   if (!gpr_unref(&t->refs)) return;
   destruct_transport(exec_ctx, t);
 }
 
 void grpc_chttp2_ref_transport(grpc_chttp2_transport *t, const char *reason,
                                const char *file, int line) {
-  gpr_log(GPR_DEBUG, "chttp2:  ref:%p %" PRIdPTR "->%" PRIdPTR " %s [%s:%d]", t,
-          t->refs.count, t->refs.count + 1, reason, file, line);
+  if (GRPC_TRACER_ON(grpc_trace_chttp2_refcount)) {
+    gpr_atm val = gpr_atm_no_barrier_load(&t->refs.count);
+    gpr_log(GPR_DEBUG, "chttp2:  ref:%p %" PRIdPTR "->%" PRIdPTR " %s [%s:%d]",
+            t, val, val + 1, reason, file, line);
+  }
   gpr_ref(&t->refs);
 }
 #else

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

@@ -26,6 +26,10 @@
 extern grpc_tracer_flag grpc_http_trace;
 extern grpc_tracer_flag grpc_flowctl_trace;
 
+#ifndef NDEBUG
+extern grpc_tracer_flag grpc_trace_chttp2_refcount;
+#endif
+
 grpc_transport *grpc_create_chttp2_transport(
     grpc_exec_ctx *exec_ctx, const grpc_channel_args *channel_args,
     grpc_endpoint *ep, int is_client);

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

@@ -764,8 +764,7 @@ void grpc_chttp2_stream_ref(grpc_chttp2_stream *s);
 void grpc_chttp2_stream_unref(grpc_exec_ctx *exec_ctx, grpc_chttp2_stream *s);
 #endif
 
-//#define GRPC_CHTTP2_REFCOUNTING_DEBUG 1
-#ifdef GRPC_CHTTP2_REFCOUNTING_DEBUG
+#ifndef NDEBUG
 #define GRPC_CHTTP2_REF_TRANSPORT(t, r) \
   grpc_chttp2_ref_transport(t, r, __FILE__, __LINE__)
 #define GRPC_CHTTP2_UNREF_TRANSPORT(cl, t, r) \