Changed the expansion of new space to depend on how much has survived scaveng...

src/heap.cc

 // Copyright 2009 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 61 matching lines @@
 int Heap::old_gen_promotion_limit_ = kMinimumPromotionLimit;
 int Heap::old_gen_allocation_limit_ = kMinimumAllocationLimit;
 
 int Heap::old_gen_exhausted_ = false;
 
 int Heap::amount_of_external_allocated_memory_ = 0;
 int Heap::amount_of_external_allocated_memory_at_last_global_gc_ = 0;
 
 // semispace_size_ should be a power of 2 and old_generation_size_ should be
 // a multiple of Page::kPageSize.
-int Heap::semispace_size_  = 2*MB;
+int Heap::semispace_size_  = 8*MB;
 int Heap::old_generation_size_ = 512*MB;
-int Heap::initial_semispace_size_ = 256*KB;
+int Heap::initial_semispace_size_ = 512*KB;
 
 GCCallback Heap::global_gc_prologue_callback_ = NULL;
 GCCallback Heap::global_gc_epilogue_callback_ = NULL;
 
 // Variables set based on semispace_size_ and old_generation_size_ in
 // ConfigureHeap.
 int Heap::young_generation_size_ = 0;  // Will be 2 * semispace_size_.
 
-// Double the new space after this many scavenge collections.
-int Heap::new_space_growth_limit_ = 8;
-int Heap::scavenge_count_ = 0;
+int Heap::survived_since_last_expansion_ = 0;
+
 Heap::HeapState Heap::gc_state_ = NOT_IN_GC;
 
 int Heap::mc_count_ = 0;
 int Heap::gc_count_ = 0;
 
 int Heap::always_allocate_scope_depth_ = 0;
 bool Heap::context_disposed_pending_ = false;
 
 #ifdef DEBUG
 bool Heap::allocation_allowed_ = true;
@@ skipping 308 matching lines @@
     global_gc_prologue_callback_();
   }
 
   if (collector == MARK_COMPACTOR) {
     MarkCompact(tracer);
 
     int old_gen_size = PromotedSpaceSize();
     old_gen_promotion_limit_ =
         old_gen_size + Max(kMinimumPromotionLimit, old_gen_size / 3);
     old_gen_allocation_limit_ =
-        old_gen_size + Max(kMinimumAllocationLimit, old_gen_size / 3);
+        old_gen_size + Max(kMinimumAllocationLimit, old_gen_size / 2);
     old_gen_exhausted_ = false;
 
     // If we have used the mark-compact collector to collect the new
     // space, and it has not compacted the new space, we force a
     // separate scavenge collection.  This is a hack.  It covers the
     // case where (1) a new space collection was requested, (2) the
     // collector selection policy selected the mark-compact collector,
     // and (3) the mark-compact collector policy selected not to
     // compact the new space.  In that case, there is no more (usable)
     // free space in the new space after the collection compared to
@@ skipping 182 matching lines @@
 void Heap::Scavenge() {
 #ifdef DEBUG
   if (FLAG_enable_slow_asserts) VerifyNonPointerSpacePointers();
 #endif
 
   gc_state_ = SCAVENGE;
 
   // Implements Cheney's copying algorithm
   LOG(ResourceEvent("scavenge", "begin"));
 
-  scavenge_count_++;
+  // Used for updating survived_since_last_expansion_ at function end.
+  int survived_watermark = PromotedSpaceSize();
+
   if (new_space_.Capacity() < new_space_.MaximumCapacity() &&
-      scavenge_count_ > new_space_growth_limit_) {
-    // Double the size of the new space, and double the limit.  The next
-    // doubling attempt will occur after the current new_space_growth_limit_
-    // more collections.
+      survived_since_last_expansion_ > new_space_.Capacity()) {
+    // Double the size of new space if there is room to grow and enough
+    // data has survived scavenge since the last expansion.
     // TODO(1240712): NewSpace::Double has a return value which is
     // ignored here.
     new_space_.Double();
-    new_space_growth_limit_ *= 2;
+    survived_since_last_expansion_ = 0;
   }
 
   // Flip the semispaces.  After flipping, to space is empty, from space has
   // live objects.
   new_space_.Flip();
   new_space_.ResetAllocationInfo();
 
   // We need to sweep newly copied objects which can be either in the
   // to space or promoted to the old generation.  For to-space
   // objects, we treat the bottom of the to space as a queue.  Newly
@@ skipping 83 matching lines @@
       UpdateRSet(target);
     }
 
     // Take another spin if there are now unswept objects in new space
     // (there are currently no more unswept promoted objects).
   } while (new_space_front < new_space_.top());
 
   // Set age mark.
   new_space_.set_age_mark(new_space_.top());
 
+  // Update how much has survivived scavenge.

[Kasper Lund, 2009/06/12 11:04:45]

survivived -> survived

+  survived_since_last_expansion_ +=
+      PromotedSpaceSize() + new_space_.Size() - survived_watermark;

[Kasper Lund, 2009/06/12 11:04:45]

Maybe reorder these to make it (crystal) clear that you're adding
new_space_.Size() and the promoted space growth to the last expansion variable.

+
   LOG(ResourceEvent("scavenge", "end"));
 
   gc_state_ = NOT_IN_GC;
 }
 
 
 void Heap::ClearRSetRange(Address start, int size_in_bytes) {
   uint32_t start_bit;
   Address start_word_address =
       Page::ComputeRSetBitPosition(start, 0, &start_bit);
@@ skipping 2721 matching lines @@
 #ifdef DEBUG
 bool Heap::GarbageCollectionGreedyCheck() {
   ASSERT(FLAG_gc_greedy);
   if (Bootstrapper::IsActive()) return true;
   if (disallow_allocation_failure()) return true;
   return CollectGarbage(0, NEW_SPACE);
 }
 #endif
 
 } }  // namespace v8::internal