Merge "Guard pause histogram with lock."
diff --git a/runtime/gc/collector/garbage_collector.cc b/runtime/gc/collector/garbage_collector.cc
index 46d79bf..646c032 100644
--- a/runtime/gc/collector/garbage_collector.cc
+++ b/runtime/gc/collector/garbage_collector.cc
@@ -55,7 +55,8 @@
     : heap_(heap),
       name_(name),
       pause_histogram_((name_ + " paused").c_str(), kPauseBucketSize, kPauseBucketCount),
-      cumulative_timings_(name) {
+      cumulative_timings_(name),
+      pause_histogram_lock_("pause histogram lock", kDefaultMutexLevel, true) {
   ResetCumulativeStatistics();
 }
 
@@ -65,10 +66,11 @@
 
 void GarbageCollector::ResetCumulativeStatistics() {
   cumulative_timings_.Reset();
-  pause_histogram_.Reset();
   total_time_ns_ = 0;
   total_freed_objects_ = 0;
   total_freed_bytes_ = 0;
+  MutexLock mu(Thread::Current(), pause_histogram_lock_);
+  pause_histogram_.Reset();
 }
 
 void GarbageCollector::Run(GcCause gc_cause, bool clear_soft_references) {
@@ -95,6 +97,7 @@
   }
   total_time_ns_ += current_iteration->GetDurationNs();
   for (uint64_t pause_time : current_iteration->GetPauseTimes()) {
+    MutexLock mu(self, pause_histogram_lock_);
     pause_histogram_.AddValue(pause_time / 1000);
   }
   ATRACE_END();
@@ -137,8 +140,11 @@
 }
 
 void GarbageCollector::ResetMeasurements() {
+  {
+    MutexLock mu(Thread::Current(), pause_histogram_lock_);
+    pause_histogram_.Reset();
+  }
   cumulative_timings_.Reset();
-  pause_histogram_.Reset();
   total_time_ns_ = 0;
   total_freed_objects_ = 0;
   total_freed_bytes_ = 0;
@@ -171,6 +177,36 @@
   heap_->RecordFree(freed.objects, freed.bytes);
 }
 
+uint64_t GarbageCollector::GetTotalPausedTimeNs() {
+  MutexLock mu(Thread::Current(), pause_histogram_lock_);
+  return pause_histogram_.AdjustedSum();
+}
+
+void GarbageCollector::DumpPerformanceInfo(std::ostream& os) {
+  const CumulativeLogger& logger = GetCumulativeTimings();
+  const size_t iterations = logger.GetIterations();
+  if (iterations == 0) {
+    return;
+  }
+  os << ConstDumpable<CumulativeLogger>(logger);
+  const uint64_t total_ns = logger.GetTotalNs();
+  double seconds = NsToMs(logger.GetTotalNs()) / 1000.0;
+  const uint64_t freed_bytes = GetTotalFreedBytes();
+  const uint64_t freed_objects = GetTotalFreedObjects();
+  {
+    MutexLock mu(Thread::Current(), pause_histogram_lock_);
+    Histogram<uint64_t>::CumulativeData cumulative_data;
+    pause_histogram_.CreateHistogram(&cumulative_data);
+    pause_histogram_.PrintConfidenceIntervals(os, 0.99, cumulative_data);
+  }
+  os << GetName() << " total time: " << PrettyDuration(total_ns)
+     << " mean time: " << PrettyDuration(total_ns / iterations) << "\n"
+     << GetName() << " freed: " << freed_objects
+     << " objects with total size " << PrettySize(freed_bytes) << "\n"
+     << GetName() << " throughput: " << freed_objects / seconds << "/s / "
+     << PrettySize(freed_bytes / seconds) << "/s\n";
+}
+
 }  // namespace collector
 }  // namespace gc
 }  // namespace art
diff --git a/runtime/gc/collector/garbage_collector.h b/runtime/gc/collector/garbage_collector.h
index 885569e..b809469 100644
--- a/runtime/gc/collector/garbage_collector.h
+++ b/runtime/gc/collector/garbage_collector.h
@@ -119,18 +119,13 @@
 
   GarbageCollector(Heap* heap, const std::string& name);
   virtual ~GarbageCollector() { }
-
   const char* GetName() const {
     return name_.c_str();
   }
-
   virtual GcType GetGcType() const = 0;
-
   virtual CollectorType GetCollectorType() const = 0;
-
   // Run the garbage collector.
   void Run(GcCause gc_cause, bool clear_soft_references);
-
   Heap* GetHeap() const {
     return heap_;
   }
@@ -138,24 +133,17 @@
   const CumulativeLogger& GetCumulativeTimings() const {
     return cumulative_timings_;
   }
-
   void ResetCumulativeStatistics();
-
   // Swap the live and mark bitmaps of spaces that are active for the collector. For partial GC,
   // this is the allocation space, for full GC then we swap the zygote bitmaps too.
   void SwapBitmaps() EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_);
-  uint64_t GetTotalPausedTimeNs() const {
-    return pause_histogram_.AdjustedSum();
-  }
+  uint64_t GetTotalPausedTimeNs() LOCKS_EXCLUDED(pause_histogram_lock_);
   int64_t GetTotalFreedBytes() const {
     return total_freed_bytes_;
   }
   uint64_t GetTotalFreedObjects() const {
     return total_freed_objects_;
   }
-  const Histogram<uint64_t>& GetPauseHistogram() const {
-    return pause_histogram_;
-  }
   // Reset the cumulative timings and pause histogram.
   void ResetMeasurements();
   // Returns the estimated throughput in bytes / second.
@@ -174,11 +162,11 @@
   void RecordFree(const ObjectBytePair& freed);
   // Record a free of large objects.
   void RecordFreeLOS(const ObjectBytePair& freed);
+  void DumpPerformanceInfo(std::ostream& os) LOCKS_EXCLUDED(pause_histogram_lock_);
 
  protected:
   // Run all of the GC phases.
   virtual void RunPhases() = 0;
-
   // Revoke all the thread-local buffers.
   virtual void RevokeAllThreadLocalBuffers() = 0;
 
@@ -188,11 +176,12 @@
   Heap* const heap_;
   std::string name_;
   // Cumulative statistics.
-  Histogram<uint64_t> pause_histogram_;
+  Histogram<uint64_t> pause_histogram_ GUARDED_BY(pause_histogram_lock_);
   uint64_t total_time_ns_;
   uint64_t total_freed_objects_;
   int64_t total_freed_bytes_;
   CumulativeLogger cumulative_timings_;
+  mutable Mutex pause_histogram_lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
 };
 
 }  // namespace collector
diff --git a/runtime/gc/heap.cc b/runtime/gc/heap.cc
index 02cd25c..b61105f 100644
--- a/runtime/gc/heap.cc
+++ b/runtime/gc/heap.cc
@@ -772,28 +772,9 @@
   // Dump cumulative loggers for each GC type.
   uint64_t total_paused_time = 0;
   for (auto& collector : garbage_collectors_) {
-    const CumulativeLogger& logger = collector->GetCumulativeTimings();
-    const size_t iterations = logger.GetIterations();
-    const Histogram<uint64_t>& pause_histogram = collector->GetPauseHistogram();
-    if (iterations != 0 && pause_histogram.SampleSize() != 0) {
-      os << ConstDumpable<CumulativeLogger>(logger);
-      const uint64_t total_ns = logger.GetTotalNs();
-      const uint64_t total_pause_ns = collector->GetTotalPausedTimeNs();
-      double seconds = NsToMs(logger.GetTotalNs()) / 1000.0;
-      const uint64_t freed_bytes = collector->GetTotalFreedBytes();
-      const uint64_t freed_objects = collector->GetTotalFreedObjects();
-      Histogram<uint64_t>::CumulativeData cumulative_data;
-      pause_histogram.CreateHistogram(&cumulative_data);
-      pause_histogram.PrintConfidenceIntervals(os, 0.99, cumulative_data);
-      os << collector->GetName() << " total time: " << PrettyDuration(total_ns)
-         << " mean time: " << PrettyDuration(total_ns / iterations) << "\n"
-         << collector->GetName() << " freed: " << freed_objects
-         << " objects with total size " << PrettySize(freed_bytes) << "\n"
-         << collector->GetName() << " throughput: " << freed_objects / seconds << "/s / "
-         << PrettySize(freed_bytes / seconds) << "/s\n";
-      total_duration += total_ns;
-      total_paused_time += total_pause_ns;
-    }
+    total_duration += collector->GetCumulativeTimings().GetTotalNs();
+    total_paused_time += collector->GetTotalPausedTimeNs();
+    collector->DumpPerformanceInfo(os);
     collector->ResetMeasurements();
   }
   uint64_t allocation_time =