Merge branch 'faster_timer_pool' into ALL-the-things

src/core/lib/iomgr/timer_generic.c

@@ -433,7 +433,7 @@ static grpc_timer_check_result run_some_expired_timers(grpc_exec_ctx *exec_ctx,
   gpr_tls_set(&g_last_seen_min_timer, min_timer);
   if (now < min_timer) {
     if (next != NULL) *next = GPR_MIN(*next, min_timer);
-    return 0;
+    return GRPC_TIMERS_CHECKED_AND_EMPTY;
   }
 
   if (gpr_spinlock_trylock(&g_shared_mutables.checker_mu)) {
@@ -553,8 +553,7 @@ grpc_timer_check_result grpc_timer_check(grpc_exec_ctx *exec_ctx,
       gpr_asprintf(&next_str, "%" PRId64 ".%09d [%" PRIdPTR "]", next->tv_sec,
                    next->tv_nsec, next_atm);
     }
-    gpr_log(GPR_DEBUG, "TIMER CHECK END: %d timers triggered; next=%s", r,
-            next_str);
+    gpr_log(GPR_DEBUG, "TIMER CHECK END: r=%d; next=%s", r, next_str);
     gpr_free(next_str);
   }
   return r;

src/core/lib/iomgr/timer_manager.c

@@ -143,7 +143,10 @@ static bool wait_until(gpr_timespec next) {
   const gpr_timespec inf_future = gpr_inf_future(GPR_CLOCK_MONOTONIC);
   gpr_mu_lock(&g_mu);
   // if we're not threaded anymore, leave
-  if (!g_threaded) return false;
+  if (!g_threaded) {
+    gpr_mu_unlock(&g_mu);
+    return false;
+  }
   // if there's no timed waiter, we should become one: that waiter waits
   // only until the next timer should expire
   // all other timers wait forever
@@ -155,7 +158,9 @@ static bool wait_until(gpr_timespec next) {
     // figure stuff out instead of incurring a wakeup)
     my_timed_waiter_generation = ++g_timed_waiter_generation;
     if (GRPC_TRACER_ON(grpc_timer_check_trace)) {
-      gpr_log(GPR_DEBUG, "sleep for a while");
+      gpr_timespec wait_time = gpr_time_sub(next, gpr_now(GPR_CLOCK_MONOTONIC));
+      gpr_log(GPR_DEBUG, "sleep for a %" PRId64 ".%09d seconds",
+              wait_time.tv_sec, wait_time.tv_nsec);
     }
   } else {
     next = inf_future;
@@ -204,6 +209,9 @@ static void timer_main_loop(grpc_exec_ctx *exec_ctx) {
 
            Consequently, we can just sleep forever here and be happy at some
            saved wakeup cycles. */
+        if (GRPC_TRACER_ON(grpc_timer_check_trace)) {
+          gpr_log(GPR_DEBUG, "timers not checked: expect another thread to");
+        }
         next = inf_future;
       /* fall through */
       case GRPC_TIMERS_CHECKED_AND_EMPTY:

src/core/lib/support/log.c

@@ -43,7 +43,7 @@
 #include <string.h>
 
 extern void gpr_default_log(gpr_log_func_args *args);
-static gpr_log_func g_log_func = gpr_default_log;
+static gpr_atm g_log_func = (gpr_atm)gpr_default_log;
 static gpr_atm g_min_severity_to_print = GPR_LOG_VERBOSITY_UNSET;
 
 const char *gpr_log_severity_string(gpr_log_severity severity) {
@@ -70,7 +70,7 @@ void gpr_log_message(const char *file, int line, gpr_log_severity severity,
   lfargs.line = line;
   lfargs.severity = severity;
   lfargs.message = message;
-  g_log_func(&lfargs);
+  ((gpr_log_func)gpr_atm_no_barrier_load(&g_log_func))(&lfargs);
 }
 
 void gpr_set_log_verbosity(gpr_log_severity min_severity_to_print) {
@@ -99,5 +99,5 @@ void gpr_log_verbosity_init() {
 }
 
 void gpr_set_log_function(gpr_log_func f) {
-  g_log_func = f ? f : gpr_default_log;
+  gpr_atm_no_barrier_store(&g_log_func, (gpr_atm)(f ? f : gpr_default_log));
 }