Core infrastructure for timer manager debug

src/core/lib/gpr/sync_posix.cc

@@ -27,6 +27,15 @@
 #include <time.h>
 #include "src/core/lib/profiling/timers.h"
 
+// For debug only. Forward statistics to another module.
+void (*g_grpc_debug_timer_manager_stats)(int64_t timer_manager_init_count, int64_t timer_manager_shutdown_count, int64_t fork_count, int64_t timer_wait_err, int64_t timer_wait_cv) = nullptr;
+// For debug only. Variables storing the counters being logged.
+int64_t g_timer_manager_init_count = 0;
+int64_t g_timer_manager_shutdown_count = 0;
+int64_t g_fork_count = 0;
+int64_t g_timer_wait_err = 0;
+int64_t g_timer_wait_cv = 0;
+
 #ifdef GPR_LOW_LEVEL_COUNTERS
 gpr_atm gpr_mu_locks = 0;
 gpr_atm gpr_counter_atm_cas = 0;
@@ -88,7 +97,18 @@ int gpr_cv_wait(gpr_cv* cv, gpr_mu* mu, gpr_timespec abs_deadline) {
     abs_deadline_ts.tv_nsec = abs_deadline.tv_nsec;
     err = pthread_cond_timedwait(cv, mu, &abs_deadline_ts);
   }
+  if (!(err == 0 || err == ETIMEDOUT || err == EAGAIN)) {
+    if (g_grpc_debug_timer_manager_stats) {
+      g_timer_wait_err = err;
+      g_timer_wait_cv = (int64_t)cv;
+      g_grpc_debug_timer_manager_stats(g_timer_manager_init_count,
+                                       g_timer_manager_shutdown_count,
+                                       g_fork_count,
+                                       g_timer_wait_err,
+                                       g_timer_wait_cv);
+    }
     GPR_ASSERT(err == 0 || err == ETIMEDOUT || err == EAGAIN);
+  }
   return err == ETIMEDOUT;
 }
 

src/core/lib/iomgr/timer_manager.cc

@@ -61,6 +61,15 @@ static uint64_t g_timed_waiter_generation;
 
 static void timer_thread(void* completed_thread_ptr);
 
+// For debug only. Forward statistics to another module.
+extern void (*g_grpc_debug_timer_manager_stats)(int64_t timer_manager_init_count, int64_t timer_manager_shutdown_count, int64_t fork_count, int64_t timer_wait_err, int64_t timer_wait_cv);
+// For debug only. Variables storing the counters being logged.
+extern int64_t g_timer_manager_init_count;
+extern int64_t g_timer_manager_shutdown_count;
+extern int64_t g_fork_count;
+extern int64_t g_timer_wait_err;
+extern int64_t g_timer_wait_cv;
+
 static void gc_completed_threads(void) {
   if (g_completed_threads != nullptr) {
     completed_thread* to_gc = g_completed_threads;
@@ -285,6 +294,7 @@ void grpc_timer_manager_init(void) {
   gpr_mu_init(&g_mu);
   gpr_cv_init(&g_cv_wait);
   gpr_cv_init(&g_cv_shutdown);
+  g_timer_manager_init_count++;
   g_threaded = false;
   g_thread_count = 0;
   g_waiter_count = 0;
@@ -319,6 +329,7 @@ static void stop_threads(void) {
 }
 
 void grpc_timer_manager_shutdown(void) {
+  g_timer_manager_shutdown_count++;
   stop_threads();
 
   gpr_mu_destroy(&g_mu);
@@ -327,6 +338,7 @@ void grpc_timer_manager_shutdown(void) {
 }
 
 void grpc_timer_manager_set_threading(bool threaded) {
+  g_fork_count++;
   if (threaded) {
     start_threads();
   } else {