Revert 10502 (smaller number string cache) due to test failures.

Review URL: https://chromiumcodereview.appspot.com/9113060

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10504 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/heap.cc

@@ -902,7 +902,8 @@ void Heap::MarkCompactPrologue() {
 
   CompletelyClearInstanceofCache();
 
-  FlushNumberStringCache();
+  // TODO(1605) select heuristic for flushing NumberString cache with
+  // FlushNumberStringCache
   if (FLAG_cleanup_code_caches_at_gc) {
     polymorphic_code_cache()->set_cache(undefined_value());
   }
@@ -2511,10 +2512,7 @@ bool Heap::CreateInitialObjects() {
   }
   set_intrinsic_function_names(StringDictionary::cast(obj));
 
-  { MaybeObject* maybe_obj = AllocateInitialNumberStringCache();
-    if (!maybe_obj->ToObject(&obj)) return false;
-  }
-  set_number_string_cache(FixedArray::cast(obj));
+  if (InitializeNumberStringCache()->IsFailure()) return false;
 
   // Allocate cache for single character ASCII strings.
   { MaybeObject* maybe_obj =
@@ -2624,41 +2622,17 @@ void StringSplitCache::Clear(FixedArray* cache) {
 }
 
 
-MaybeObject* Heap::AllocateInitialNumberStringCache() {
-  MaybeObject* maybe_obj =
-      AllocateFixedArray(kInitialNumberStringCacheSize * 2, TENURED);
-  return maybe_obj;
-}
-
-
-int Heap::FullSizeNumberStringCacheLength() {
-  // Compute the size of the number string cache based on the max newspace size.
-  // The number string cache has a minimum size based on twice the initial cache
-  // size to ensure that it is bigger after being made 'full size'.
+MaybeObject* Heap::InitializeNumberStringCache() {
+  // Compute the size of the number string cache based on the max heap size.
+  // max_semispace_size_ == 512 KB => number_string_cache_size = 32.
+  // max_semispace_size_ ==   8 MB => number_string_cache_size = 16KB.
   int number_string_cache_size = max_semispace_size_ / 512;
-  number_string_cache_size = Max(kInitialNumberStringCacheSize * 2,
-                                 Min(0x4000, number_string_cache_size));
-  // There is a string and a number per entry so the length is twice the number
-  // of entries.
-  return number_string_cache_size * 2;
-}
-
-
-void Heap::AllocateFullSizeNumberStringCache() {
-  // The idea is to have a small number string cache in the snapshot to keep
-  // boot-time memory usage down.  If we expand the number string cache already
-  // while creating the snapshot then that didn't work out.
-  ASSERT(!Serializer::enabled());
+  number_string_cache_size = Max(32, Min(16*KB, number_string_cache_size));
+  Object* obj;
   MaybeObject* maybe_obj =
-      AllocateFixedArray(FullSizeNumberStringCacheLength(), TENURED);
-  Object* new_cache;
-  if (maybe_obj->ToObject(&new_cache)) {
-    // We don't bother to repopulate the cache with entries from the old cache.
-    // It will be repopulated soon enough with new strings.
-    set_number_string_cache(FixedArray::cast(new_cache));
-  }
-  // If allocation fails then we just return without doing anything.  It is only
-  // a cache, so best effort is OK here.
+      AllocateFixedArray(number_string_cache_size * 2, TENURED);
+  if (maybe_obj->ToObject(&obj)) set_number_string_cache(FixedArray::cast(obj));
+  return maybe_obj;
 }
 
 
@@ -2707,17 +2681,11 @@ void Heap::SetNumberStringCache(Object* number, String* string) {
   int mask = (number_string_cache()->length() >> 1) - 1;
   if (number->IsSmi()) {
     hash = smi_get_hash(Smi::cast(number)) & mask;
+    number_string_cache()->set(hash * 2, Smi::cast(number));
   } else {
     hash = double_get_hash(number->Number()) & mask;
-  }
-  if (number_string_cache()->get(hash * 2) != undefined_value() &&
-      number_string_cache()->length() != FullSizeNumberStringCacheLength()) {
-    // The first time we have a hash collision, we move to the full sized
-    // number string cache.
-    AllocateFullSizeNumberStringCache();
-    return;
-  }
     number_string_cache()->set(hash * 2, number);
+  }
   number_string_cache()->set(hash * 2 + 1, string);
 }
 

src/heap.h

@@ -1798,13 +1798,8 @@ class Heap {
   GCTracer* tracer_;
 
 
-  // Allocates a small number to string cache.
-  MUST_USE_RESULT MaybeObject* AllocateInitialNumberStringCache();
-  // Creates and installs the full-sized number string cache.
-  void AllocateFullSizeNumberStringCache();
-  // Get the length of the number to string cache based on the max semispace
-  // size.
-  int FullSizeNumberStringCacheLength();
+  // 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();
 
@@ -1901,7 +1896,6 @@ class Heap {
 
   static const int kInitialSymbolTableSize = 2048;
   static const int kInitialEvalCacheSize = 64;
-  static const int kInitialNumberStringCacheSize = 256;
 
   // Maximum GC pause.
   int max_gc_pause_;

test/cctest/test-mark-compact.cc

@@ -540,7 +540,7 @@ TEST(BootUpMemoryUse) {
       }
     } else {
       if (v8::internal::Snapshot::IsEnabled()) {
-        CHECK_LE(booted_memory - initial_memory, 6500 * 1024);  // 6356.
+        CHECK_LE(booted_memory - initial_memory, 6500 * 1024);  // 6365.
       } else {
         CHECK_LE(booted_memory - initial_memory, 6654 * 1024);  // 6424
       }