Perform smaller marking steps incrementally in idle notification.

src/heap/gc-idle-time-handler.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/heap/gc-idle-time-handler.h"
 #include "src/heap/gc-tracer.h"
 #include "src/utils.h"
 
 namespace v8 {
 namespace internal {
 
 const double GCIdleTimeHandler::kConservativeTimeRatio = 0.9;
 const size_t GCIdleTimeHandler::kMaxMarkCompactTimeInMs = 1000;
 const size_t GCIdleTimeHandler::kMaxFinalIncrementalMarkCompactTimeInMs = 1000;
 const size_t GCIdleTimeHandler::kMinTimeForFinalizeSweeping = 100;
 const int GCIdleTimeHandler::kMaxMarkCompactsInIdleRound = 7;
 const int GCIdleTimeHandler::kIdleScavengeThreshold = 5;
 const double GCIdleTimeHandler::kHighContextDisposalRate = 100;
 
 
 void GCIdleTimeAction::Print() {
   switch (type) {
     case DONE:
       PrintF("done");
       break;
     case DO_NOTHING:
       PrintF("no action");
       break;
     case DO_INCREMENTAL_MARKING:
-      PrintF("incremental marking with step %" V8_PTR_PREFIX "d", parameter);
+      PrintF("incremental marking with step %" V8_PTR_PREFIX "d / ms",
+             parameter);
       break;
     case DO_SCAVENGE:
       PrintF("scavenge");
       break;
     case DO_FULL_GC:
       PrintF("full GC");
       break;
     case DO_FINALIZE_SWEEPING:
       PrintF("finalize sweeping");
       break;
@@ skipping 202 matching lines @@
   if (heap_state.sweeping_in_progress &&
       static_cast<size_t>(idle_time_in_ms) >= kMinTimeForFinalizeSweeping) {
     return GCIdleTimeAction::FinalizeSweeping();
   }
 
   if (heap_state.incremental_marking_stopped &&
       !heap_state.can_start_incremental_marking) {
     return GCIdleTimeAction::Nothing();
   }
   size_t step_size = EstimateMarkingStepSize(
-      static_cast<size_t>(idle_time_in_ms),
+      static_cast<size_t>(kIncrementalMarkingStepTimeInMs),
       heap_state.incremental_marking_speed_in_bytes_per_ms);
   return GCIdleTimeAction::IncrementalMarking(step_size);
 }
 }
 }