[heap] Remove js call rate heuristic from memory reducer.

src/heap/memory-reducer.cc

Index: src/heap/memory-reducer.cc
diff --git a/src/heap/memory-reducer.cc b/src/heap/memory-reducer.cc
index 22d0b482666b69951ba53f472909f9b5114bc40e..2aed4c714a38064d7091a908229c062e2e5a4b3f 100644
--- a/src/heap/memory-reducer.cc
+++ b/src/heap/memory-reducer.cc
@@ -24,19 +24,16 @@ MemoryReducer::TimerTask::TimerTask(MemoryReducer* memory_reducer)
 
 
 void MemoryReducer::TimerTask::RunInternal() {
-  const double kJsCallsPerMsThreshold = 0.5;
   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) {
     heap->isolate()->PrintWithTimestamp(
-        "Memory reducer: call rate %.3lf, %s, %s\n", js_call_rate,
+        "Memory reducer: %s, %s\n",
         low_allocation_rate ? "low alloc" : "high alloc",
         optimize_for_memory ? "background" : "foreground");
   }
@@ -45,7 +42,8 @@ void MemoryReducer::TimerTask::RunInternal() {
   // 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.should_start_incremental_gc =
+      low_allocation_rate || optimize_for_memory;
   event.can_start_incremental_gc =
       heap->incremental_marking()->IsStopped() &&
       (heap->incremental_marking()->CanBeActivated() || optimize_for_memory);
@@ -53,16 +51,6 @@ 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);
@@ -196,8 +184,6 @@ MemoryReducer::State MemoryReducer::Step(const State& state,
 
 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());