Fix responsiveness of high promotion mode heuristics.

src/heap.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 1363 matching lines @@
   static inline void CopyBlock(Address dst, Address src, int byte_size);
 
   // Optimized version of memmove for blocks with pointer size aligned sizes and
   // pointer size aligned addresses.
   static inline void MoveBlock(Address dst, Address src, int byte_size);
 
   // Check new space expansion criteria and expand semispaces if it was hit.
   void CheckNewSpaceExpansionCriteria();
 
   inline void IncrementYoungSurvivorsCounter(int survived) {
+    ASSERT(survived >= 0);
     young_survivors_after_last_gc_ = survived;
     survived_since_last_expansion_ += survived;
   }
 
   inline bool NextGCIsLikelyToBeFull() {
     if (FLAG_gc_global) return true;
 
     intptr_t total_promoted = PromotedTotalSize();
 
     intptr_t adjusted_promotion_limit =
@@ skipping 398 matching lines @@
 
   // Initializes the number to string cache based on the max semispace size.
   MUST_USE_RESULT MaybeObject* InitializeNumberStringCache();
   // Flush the number to string cache.
   void FlushNumberStringCache();
 
   void UpdateSurvivalRateTrend(int start_new_space_size);
 
   enum SurvivalRateTrend { INCREASING, STABLE, DECREASING, FLUCTUATING };
 
-  static const int kYoungSurvivalRateThreshold = 90;
+  static const int kYoungSurvivalRateHighThreshold = 90;
+  static const int kYoungSurvivalRateLowThreshold = 10;
   static const int kYoungSurvivalRateAllowedDeviation = 15;
 
   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);
     previous_survival_rate_trend_ = survival_rate_trend_;
     survival_rate_trend_ = survival_rate_trend;
   }
 
@@ skipping 12 matching lines @@
   bool IsStableOrIncreasingSurvivalTrend() {
     switch (survival_rate_trend()) {
       case STABLE:
       case INCREASING:
         return true;
       default:
         return false;
     }
   }
 
+  bool IsStableOrDecreasingSurvivalTrend() {
+    switch (survival_rate_trend()) {
+      case STABLE:
+      case DECREASING:
+        return true;
+      default:
+        return false;
+    }
+  }
+
   bool IsIncreasingSurvivalTrend() {
     return survival_rate_trend() == INCREASING;
   }
 
-  bool IsDecreasingSurvivalTrend() {
-    return survival_rate_trend() == DECREASING;
+  bool IsHighSurvivalRate() {
+    return high_survival_rate_period_length_ > 0;
   }
 
-  bool IsHighSurvivalRate() {
-    return high_survival_rate_period_length_ > 0;
+  bool IsLowSurvivalRate() {
+    return low_survival_rate_period_length_ > 0;
   }
 
   void SelectScavengingVisitorsTable();
 
   void StartIdleRound() {
     mark_sweeps_since_idle_round_started_ = 0;
     ms_count_at_last_idle_notification_ = ms_count_;
   }
 
   void FinishIdleRound() {
@@ skipping 756 matching lines @@
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 } }  // namespace v8::internal
 
 #undef HEAP
 
 #endif  // V8_HEAP_H_