New flag --stress-compaction

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 1013 matching lines @@
 
   // The hidden_symbol is special because it is the empty string, but does
   // not match the empty string.
   String* hidden_symbol() { return hidden_symbol_; }
 
   void set_global_contexts_list(Object* object) {
     global_contexts_list_ = object;
   }
   Object* global_contexts_list() { return global_contexts_list_; }
 
+  // Number of mark-sweeps.
+  int ms_count() { return ms_count_; }
+
   // Iterates over all roots in the heap.
   void IterateRoots(ObjectVisitor* v, VisitMode mode);
   // Iterates over all strong roots in the heap.
   void IterateStrongRoots(ObjectVisitor* v, VisitMode mode);
   // Iterates over all the other roots in the heap.
   void IterateWeakRoots(ObjectVisitor* v, VisitMode mode);
 
   // Iterate pointers to from semispace of new space found in memory interval
   // from start to end.
   void IterateAndMarkPointersToFromSpace(Address start,
@@ skipping 192 matching lines @@
   // timing of the next GC also need to be adjusted downwards.
   void LowerOldGenLimits(intptr_t adjustment) {
     size_of_old_gen_at_last_old_space_gc_ -= adjustment;
     old_gen_promotion_limit_ =
         OldGenPromotionLimit(size_of_old_gen_at_last_old_space_gc_);
     old_gen_allocation_limit_ =
         OldGenAllocationLimit(size_of_old_gen_at_last_old_space_gc_);
   }
 
   intptr_t OldGenPromotionLimit(intptr_t old_gen_size) {
+    const int divisor = FLAG_stress_compaction ? 10 : 3;
     intptr_t limit =
-        Max(old_gen_size + old_gen_size / 3, kMinimumPromotionLimit);
+        Max(old_gen_size + old_gen_size / divisor, kMinimumPromotionLimit);
     limit += new_space_.Capacity();
     limit *= old_gen_limit_factor_;
     return limit;
   }
 
   intptr_t OldGenAllocationLimit(intptr_t old_gen_size) {
+    const int divisor = FLAG_stress_compaction ? 8 : 2;
     intptr_t limit =
-        Max(old_gen_size + old_gen_size / 2, kMinimumAllocationLimit);
+        Max(old_gen_size + old_gen_size / divisor, kMinimumAllocationLimit);
     limit += new_space_.Capacity();
     limit *= old_gen_limit_factor_;
     return limit;
   }
 
   // Can be called when the embedding application is idle.
   bool IdleNotification();
 
   // Declare all the root indices.
   enum RootListIndex {
@@ skipping 1197 matching lines @@
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG || LIVE_OBJECT_LIST
 
 } }  // namespace v8::internal
 
 #undef HEAP
 
 #endif  // V8_HEAP_H_