Exponentially increase incremental marking factor each 512 steps.

src/incremental-marking.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 51 matching lines @@
 
   static void UpdateMarkingStackAfterScavenge();
 
   static void Hurry();
 
   static void Finalize();
 
   static void MarkingComplete();
 
   static const intptr_t kAllocatedThreshold = 1024;
-  static const intptr_t kAllocationMarkingFactor = 8;
+  static const intptr_t kInitialAllocationMarkingFactor = 8;
+  static const intptr_t kAllocationMarkingFactorSpeedupInterval = 512;
+  static const intptr_t kAllocationMarkingFactorSpeedup = 2;
 
   static void Step(intptr_t allocated);
 
   static inline void RestartIfNotMarking() {
     if (state_ == COMPLETE) {
       state_ = MARKING;
       if (FLAG_trace_incremental_marking) {
         PrintF("[IncrementalMarking] Restarting (new grey objects)\n");
       }
     }
@@ skipping 128 matching lines @@
   }
 
   static inline double steps_took() {
     return steps_took_;
   }
 
  private:
   static void ResetStepCounters() {
     steps_count_ = 0;
     steps_took_ = 0;
+    allocation_marking_factor_ = kInitialAllocationMarkingFactor;
   }
 
 
   static State state_;
   static MarkingStack marking_stack_;
 
   static int steps_count_;
   static double steps_took_;
 
+  static intptr_t allocation_marking_factor_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_INCREMENTAL_MARKING_H_