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-rw-r--r--absl/synchronization/mutex.cc16
1 files changed, 10 insertions, 6 deletions
diff --git a/absl/synchronization/mutex.cc b/absl/synchronization/mutex.cc
index c0268b62..69103ed8 100644
--- a/absl/synchronization/mutex.cc
+++ b/absl/synchronization/mutex.cc
@@ -2342,22 +2342,26 @@ ABSL_ATTRIBUTE_NOINLINE void Mutex::UnlockSlow(SynchWaitParams *waitp) {
} // end of for(;;)-loop
if (wake_list != kPerThreadSynchNull) {
- int64_t wait_cycles = 0;
+ int64_t total_wait_cycles = 0;
+ int64_t max_wait_cycles = 0;
int64_t now = base_internal::CycleClock::Now();
do {
- // Sample lock contention events only if the waiter was trying to acquire
+ // Profile lock contention events only if the waiter was trying to acquire
// the lock, not waiting on a condition variable or Condition.
if (!wake_list->cond_waiter) {
- wait_cycles += (now - wake_list->waitp->contention_start_cycles);
+ int64_t cycles_waited =
+ (now - wake_list->waitp->contention_start_cycles);
+ total_wait_cycles += cycles_waited;
+ if (max_wait_cycles == 0) max_wait_cycles = cycles_waited;
wake_list->waitp->contention_start_cycles = now;
wake_list->waitp->should_submit_contention_data = true;
}
wake_list = Wakeup(wake_list); // wake waiters
} while (wake_list != kPerThreadSynchNull);
- if (wait_cycles > 0) {
- mutex_tracer("slow release", this, wait_cycles);
+ if (total_wait_cycles > 0) {
+ mutex_tracer("slow release", this, total_wait_cycles);
ABSL_TSAN_MUTEX_PRE_DIVERT(this, 0);
- submit_profile_data(wait_cycles);
+ submit_profile_data(total_wait_cycles);
ABSL_TSAN_MUTEX_POST_DIVERT(this, 0);
}
}