Add the rate of js invocations from the api as a signal of idleness

for starting major GC in the memory reducer.

BUG=

Review URL: https://codereview.chromium.org/1414483004

Cr-Commit-Position: refs/heads/master@{#31655}

src/api.cc

@@ -159,6 +159,7 @@ class CallDepthScope {
         do_callback_(do_callback) {
     // TODO(dcarney): remove this when blink stops crashing.
     DCHECK(!isolate_->external_caught_exception());
+    isolate_->IncrementJsCallsFromApiCounter();
     isolate_->handle_scope_implementer()->IncrementCallDepth();
     if (!context_.IsEmpty()) context_->Enter();
   }

src/heap/memory-reducer.cc

@@ -13,7 +13,7 @@
 namespace v8 {
 namespace internal {
 
-const int MemoryReducer::kLongDelayMs = 20000;
+const int MemoryReducer::kLongDelayMs = 8000;
 const int MemoryReducer::kShortDelayMs = 500;
 const int MemoryReducer::kWatchdogDelayMs = 100000;
 const int MemoryReducer::kMaxNumberOfGCs = 3;
@@ -24,15 +24,27 @@ MemoryReducer::TimerTask::TimerTask(MemoryReducer* memory_reducer)
 
 
 void MemoryReducer::TimerTask::RunInternal() {
+  const double kJsCallsPerMsThreshold = 0.25;
   Heap* heap = memory_reducer_->heap();
   Event event;
   double time_ms = heap->MonotonicallyIncreasingTimeInMs();
   heap->tracer()->SampleAllocation(time_ms, heap->NewSpaceAllocationCounter(),
                                    heap->OldGenerationAllocationCounter());
+  double js_call_rate = memory_reducer_->SampleAndGetJsCallsPerMs(time_ms);
+  bool low_allocation_rate = heap->HasLowAllocationRate();
+  bool is_idle = js_call_rate < kJsCallsPerMsThreshold && low_allocation_rate;
+  bool optimize_for_memory = heap->ShouldOptimizeForMemoryUsage();
+  if (FLAG_trace_gc_verbose) {
+    PrintIsolate(heap->isolate(), "Memory reducer: call rate %.3lf, %s, %s\n",
+                 js_call_rate, low_allocation_rate ? "low alloc" : "high alloc",
+                 optimize_for_memory ? "background" : "foreground");
+  }
   event.type = kTimer;
   event.time_ms = time_ms;
-  event.should_start_incremental_gc =
-      heap->HasLowAllocationRate() || heap->ShouldOptimizeForMemoryUsage();
+  // The memory reducer will start incremental markig if
+  // 1) mutator is likely idle: js call rate is low and allocation rate is low.
+  // 2) mutator is in background: optimize for memory flag is set.
+  event.should_start_incremental_gc = is_idle || optimize_for_memory;
   event.can_start_incremental_gc =
       heap->incremental_marking()->IsStopped() &&
       heap->incremental_marking()->CanBeActivated();
@@ -40,6 +52,16 @@ void MemoryReducer::TimerTask::RunInternal() {
 }
 
 
+double MemoryReducer::SampleAndGetJsCallsPerMs(double time_ms) {
+  unsigned int counter = heap()->isolate()->js_calls_from_api_counter();
+  unsigned int call_delta = counter - js_calls_counter_;
+  double time_delta_ms = time_ms - js_calls_sample_time_ms_;
+  js_calls_counter_ = counter;
+  js_calls_sample_time_ms_ = time_ms;
+  return time_delta_ms > 0 ? call_delta / time_delta_ms : 0;
+}
+
+
 void MemoryReducer::NotifyTimer(const Event& event) {
   DCHECK_EQ(kTimer, event.type);
   DCHECK_EQ(kWait, state_.action);
@@ -70,7 +92,7 @@ void MemoryReducer::NotifyTimer(const Event& event) {
           "Memory reducer: finalize incremental marking");
     }
     // Re-schedule the timer.
-    ScheduleTimer(state_.next_gc_start_ms - event.time_ms);
+    ScheduleTimer(event.time_ms, state_.next_gc_start_ms - event.time_ms);
     if (FLAG_trace_gc_verbose) {
       PrintIsolate(heap()->isolate(), "Memory reducer: waiting for %.f ms\n",
                    state_.next_gc_start_ms - event.time_ms);
@@ -85,7 +107,7 @@ void MemoryReducer::NotifyMarkCompact(const Event& event) {
   state_ = Step(state_, event);
   if (old_action != kWait && state_.action == kWait) {
     // If we are transitioning to the WAIT state, start the timer.
-    ScheduleTimer(state_.next_gc_start_ms - event.time_ms);
+    ScheduleTimer(event.time_ms, state_.next_gc_start_ms - event.time_ms);
   }
   if (old_action == kRun) {
     if (FLAG_trace_gc_verbose) {
@@ -103,7 +125,7 @@ void MemoryReducer::NotifyContextDisposed(const Event& event) {
   state_ = Step(state_, event);
   if (old_action != kWait && state_.action == kWait) {
     // If we are transitioning to the WAIT state, start the timer.
-    ScheduleTimer(state_.next_gc_start_ms - event.time_ms);
+    ScheduleTimer(event.time_ms, state_.next_gc_start_ms - event.time_ms);
   }
 }
 
@@ -172,8 +194,10 @@ MemoryReducer::State MemoryReducer::Step(const State& state,
 }
 
 
-void MemoryReducer::ScheduleTimer(double delay_ms) {
+void MemoryReducer::ScheduleTimer(double time_ms, double delay_ms) {
   DCHECK(delay_ms > 0);
+  // Record the time and the js call counter.
+  SampleAndGetJsCallsPerMs(time_ms);
   // Leave some room for precision error in task scheduler.
   const double kSlackMs = 100;
   v8::Isolate* isolate = reinterpret_cast<v8::Isolate*>(heap()->isolate());

src/heap/memory-reducer.h

@@ -107,7 +107,10 @@ class MemoryReducer {
   };
 
   explicit MemoryReducer(Heap* heap)
-      : heap_(heap), state_(kDone, 0, 0.0, 0.0) {}
+      : heap_(heap),
+        state_(kDone, 0, 0.0, 0.0),
+        js_calls_counter_(0),
+        js_calls_sample_time_ms_(0.0) {}
   // Callbacks.
   void NotifyMarkCompact(const Event& event);
   void NotifyContextDisposed(const Event& event);
@@ -116,7 +119,7 @@ class MemoryReducer {
   // the incoming event.
   static State Step(const State& state, const Event& event);
   // Posts a timer task that will call NotifyTimer after the given delay.
-  void ScheduleTimer(double delay_ms);
+  void ScheduleTimer(double time_ms, double delay_ms);
   void TearDown();
   static const int kLongDelayMs;
   static const int kShortDelayMs;
@@ -145,8 +148,16 @@ class MemoryReducer {
 
   static bool WatchdogGC(const State& state, const Event& event);
 
+  // Returns the rate of JS calls initiated from the API.
+  double SampleAndGetJsCallsPerMs(double time_ms);
+
   Heap* heap_;
   State state_;
+  unsigned int js_calls_counter_;
+  double js_calls_sample_time_ms_;
+
+  // Used in cctest.
+  friend class HeapTester;
   DISALLOW_COPY_AND_ASSIGN(MemoryReducer);
 };
 

src/isolate.cc

@@ -1792,6 +1792,7 @@ Isolate::Isolate(bool enable_serializer)
       virtual_handler_register_(NULL),
       virtual_slot_register_(NULL),
       next_optimization_id_(0),
+      js_calls_from_api_counter_(0),
 #if TRACE_MAPS
       next_unique_sfi_id_(0),
 #endif

src/isolate.h

@@ -1046,6 +1046,12 @@ class Isolate {
     return id;
   }
 
+  void IncrementJsCallsFromApiCounter() { ++js_calls_from_api_counter_; }
+
+  unsigned int js_calls_from_api_counter() {
+    return js_calls_from_api_counter_;
+  }
+
   // Get (and lazily initialize) the registry for per-isolate symbols.
   Handle<JSObject> GetSymbolRegistry();
 
@@ -1313,6 +1319,9 @@ class Isolate {
 
   int next_optimization_id_;
 
+  // Counts javascript calls from the API. Wraps around on overflow.
+  unsigned int js_calls_from_api_counter_;
+
 #if TRACE_MAPS
   int next_unique_sfi_id_;
 #endif

test/cctest/cctest.h

@@ -530,6 +530,13 @@ static inline void DisableInlineAllocationSteps(v8::internal::NewSpace* space) {
 }
 
 
+static inline void CheckDoubleEquals(double expected, double actual) {
+  const double kEpsilon = 1e-10;
+  CHECK_LE(expected, actual + kEpsilon);
+  CHECK_GE(expected, actual - kEpsilon);
+}
+
+
 static int LenFromSize(int size) {
   return (size - i::FixedArray::kHeaderSize) / i::kPointerSize;
 }

test/cctest/heap-tester.h

@@ -22,6 +22,7 @@
   V(Regression39128)                    \
   V(ResetWeakHandle)                    \
   V(StressHandles)                      \
+  V(TestMemoryReducerSampleJsCalls)     \
   V(TestSizeOfObjects)                  \
   V(WriteBarriersInCopyJSObject)
 

test/cctest/test-heap.cc

@@ -35,6 +35,7 @@
 #include "src/factory.h"
 #include "src/global-handles.h"
 #include "src/heap/gc-tracer.h"
+#include "src/heap/memory-reducer.h"
 #include "src/ic/ic.h"
 #include "src/macro-assembler.h"
 #include "src/snapshot/snapshot.h"
@@ -6274,5 +6275,30 @@ TEST(Regress519319) {
 }
 
 
+HEAP_TEST(TestMemoryReducerSampleJsCalls) {
+  CcTest::InitializeVM();
+  v8::HandleScope scope(CcTest::isolate());
+  Heap* heap = CcTest::heap();
+  Isolate* isolate = CcTest::i_isolate();
+  MemoryReducer* memory_reducer = heap->memory_reducer_;
+  memory_reducer->SampleAndGetJsCallsPerMs(0);
+  isolate->IncrementJsCallsFromApiCounter();
+  isolate->IncrementJsCallsFromApiCounter();
+  isolate->IncrementJsCallsFromApiCounter();
+  double calls_per_ms = memory_reducer->SampleAndGetJsCallsPerMs(1);
+  CheckDoubleEquals(3, calls_per_ms);
+
+  calls_per_ms = memory_reducer->SampleAndGetJsCallsPerMs(2);
+  CheckDoubleEquals(0, calls_per_ms);
+
+  isolate->IncrementJsCallsFromApiCounter();
+  isolate->IncrementJsCallsFromApiCounter();
+  isolate->IncrementJsCallsFromApiCounter();
+  isolate->IncrementJsCallsFromApiCounter();
+  calls_per_ms = memory_reducer->SampleAndGetJsCallsPerMs(4);
+  CheckDoubleEquals(2, calls_per_ms);
+}
+
+
 }  // namespace internal
 }  // namespace v8