Decrease OldSurvivalRateLowThreshold to fit heap growing strategy.

src/heap.h

 // Copyright 2012 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_H_
 #define V8_HEAP_H_
 
 #include <cmath>
 
 #include "allocation.h"
@@ skipping 2007 matching lines @@
                                      ScratchpadSlotMode mode);
 
   void UpdateSurvivalRateTrend(int start_new_space_size);
 
   enum SurvivalRateTrend { INCREASING, STABLE, DECREASING, FLUCTUATING };
 
   static const int kYoungSurvivalRateHighThreshold = 90;
   static const int kYoungSurvivalRateLowThreshold = 10;
   static const int kYoungSurvivalRateAllowedDeviation = 15;
 
-  static const int kOldSurvivalRateLowThreshold = 20;
+  static const int kOldSurvivalRateLowThreshold = 10;
 
   int young_survivors_after_last_gc_;
   int high_survival_rate_period_length_;
   int low_survival_rate_period_length_;
   double survival_rate_;
   SurvivalRateTrend previous_survival_rate_trend_;
   SurvivalRateTrend survival_rate_trend_;
 
   void set_survival_rate_trend(SurvivalRateTrend survival_rate_trend) {
     ASSERT(survival_rate_trend != FLUCTUATING);
@@ skipping 779 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_