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| author | Mathieu Chartier <mathieuc@google.com> | 2014-07-16 01:44:49 +0000 |
|---|---|---|
| committer | Gerrit Code Review <noreply-gerritcodereview@google.com> | 2014-07-15 20:36:09 +0000 |
| commit | fbde4dd1cb6db729e3f3ee5bdae0cdd824d73054 (patch) | |
| tree | 1cd54bee2823ab0b57412c10cf718e20ba9dc645 | |
| parent | ebaca192314e21d26b97646fa962e468ff07b893 (diff) | |
| parent | 251755cd511463260e60be98bf138b6aa1c14bf3 (diff) | |
| download | art-fbde4dd1cb6db729e3f3ee5bdae0cdd824d73054.zip art-fbde4dd1cb6db729e3f3ee5bdae0cdd824d73054.tar.gz art-fbde4dd1cb6db729e3f3ee5bdae0cdd824d73054.tar.bz2 | |
Merge "Use sched_yield in Monitor::MonitorEnter."
| -rw-r--r-- | runtime/monitor.cc | 6 | ||||
| -rw-r--r-- | runtime/thread_list.cc | 9 |
2 files changed, 13 insertions, 2 deletions
diff --git a/runtime/monitor.cc b/runtime/monitor.cc index 5633a77..da481e4 100644 --- a/runtime/monitor.cc +++ b/runtime/monitor.cc @@ -746,7 +746,11 @@ mirror::Object* Monitor::MonitorEnter(Thread* self, mirror::Object* obj) { contention_count++; Runtime* runtime = Runtime::Current(); if (contention_count <= runtime->GetMaxSpinsBeforeThinkLockInflation()) { - NanoSleep(1000); // Sleep for 1us and re-attempt. + // TODO: Consider switch thread state to kBlocked when we are yielding. + // Use sched_yield instead of NanoSleep since NanoSleep can wait much longer than the + // parameter you pass in. This can cause thread suspension to take excessively long + // make long pauses. See b/16307460. + sched_yield(); } else { contention_count = 0; InflateThinLocked(self, h_obj, lock_word, 0); diff --git a/runtime/thread_list.cc b/runtime/thread_list.cc index 54732fa..b649b62 100644 --- a/runtime/thread_list.cc +++ b/runtime/thread_list.cc @@ -39,6 +39,8 @@ namespace art { +static constexpr uint64_t kLongThreadSuspendThreshold = MsToNs(5); + ThreadList::ThreadList() : suspend_all_count_(0), debug_suspend_all_count_(0), thread_exit_cond_("thread exit condition variable", *Locks::thread_list_lock_) { @@ -304,8 +306,8 @@ void ThreadList::SuspendAll() { DCHECK(self != nullptr); VLOG(threads) << *self << " SuspendAll starting..."; - ATRACE_BEGIN("Suspending mutator threads"); + uint64_t start_time = NanoTime(); Locks::mutator_lock_->AssertNotHeld(self); Locks::thread_list_lock_->AssertNotHeld(self); @@ -338,6 +340,11 @@ void ThreadList::SuspendAll() { Locks::mutator_lock_->ExclusiveLock(self); #endif + uint64_t end_time = NanoTime(); + if (end_time - start_time > kLongThreadSuspendThreshold) { + LOG(WARNING) << "Suspending all threads took: " << PrettyDuration(end_time - start_time); + } + if (kDebugLocking) { // Debug check that all threads are suspended. AssertThreadsAreSuspended(self, self); |