Adjust small heap threshold for idle time handler.

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

 // 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.
 
 #ifndef V8_HEAP_GC_IDLE_TIME_HANDLER_H_
 #define V8_HEAP_GC_IDLE_TIME_HANDLER_H_
 
 #include "src/globals.h"
 
 namespace v8 {
@@ skipping 90 matching lines @@
 
   // Number of idle mark-compact events, after which idle handler will finish
   // idle round.
   static const int kMaxMarkCompactsInIdleRound;
 
   // Number of scavenges that will trigger start of new idle round.
   static const int kIdleScavengeThreshold;
 
   // Heap size threshold below which we prefer mark-compact over incremental
   // step.
-  static const size_t kSmallHeapSize = 2 * kPointerSize * MB;
+  static const size_t kSmallHeapSize = 4 * kPointerSize * MB;
 
   // That is the maximum idle time we will have during frame rendering.
   static const size_t kMaxFrameRenderingIdleTime = 16;
 
   // If less than that much memory is left in the new space, we consider it
   // as almost full and force a new space collection earlier in the idle time.
   static const size_t kNewSpaceAlmostFullTreshold = 100 * KB;
 
   // If we haven't recorded any scavenger events yet, we use a conservative
   // lower bound for the scavenger speed.
@@ skipping 57 matching lines @@
   int mark_compacts_since_idle_round_started_;
   int scavenges_since_last_idle_round_;
 
   DISALLOW_COPY_AND_ASSIGN(GCIdleTimeHandler);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_GC_IDLE_TIME_HANDLER_H_