Make the speed of incrmental marking depend also on the rate

src/ia32/code-stubs-ia32.cc

Index: src/ia32/code-stubs-ia32.cc
===================================================================
--- src/ia32/code-stubs-ia32.cc	(revision 12583)
+++ src/ia32/code-stubs-ia32.cc	(working copy)
@@ -7326,6 +7326,17 @@
     Mode mode) {
   Label object_is_black, need_incremental, need_incremental_pop_object;
 
+  __ mov(regs_.scratch0(), Immediate(~Page::kPageAlignmentMask));
+  __ and_(regs_.scratch0(), regs_.object());
+  __ mov(regs_.scratch1(),
+         Operand(regs_.scratch0(),
+                 MemoryChunk::kWriteBarrierCounterOffset));
+  __ sub(regs_.scratch1(), Immediate(1));
+  __ mov(Operand(regs_.scratch0(),
+                 MemoryChunk::kWriteBarrierCounterOffset),
+         regs_.scratch1());
+  __ j(negative, &need_incremental);
+
   // Let's look at the color of the object:  If it is not black we don't have
   // to inform the incremental marker.
   __ JumpIfBlack(regs_.object(),