Title: [92092] trunk/Source/_javascript_Core
- Revision
- 92092
- Author
- [email protected]
- Date
- 2011-07-31 16:48:27 -0700 (Sun, 31 Jul 2011)
Log Message
JSC GC lays out size classes under wrong assumptions about expected
object size.
https://bugs.webkit.org/show_bug.cgi?id=65437
Reviewed by Oliver Hunt.
Changed the atom size - which is both the smallest allocation size and
the smallest possible stepping unit for size class spacing - from
8 bytes to 4 pointer-size words. This is a 1% win on SunSpider.
* heap/MarkedBlock.h:
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (92091 => 92092)
--- trunk/Source/_javascript_Core/ChangeLog 2011-07-31 23:17:24 UTC (rev 92091)
+++ trunk/Source/_javascript_Core/ChangeLog 2011-07-31 23:48:27 UTC (rev 92092)
@@ -1,5 +1,19 @@
2011-07-31 Filip Pizlo <[email protected]>
+ JSC GC lays out size classes under wrong assumptions about expected
+ object size.
+ https://bugs.webkit.org/show_bug.cgi?id=65437
+
+ Reviewed by Oliver Hunt.
+
+ Changed the atom size - which is both the smallest allocation size and
+ the smallest possible stepping unit for size class spacing - from
+ 8 bytes to 4 pointer-size words. This is a 1% win on SunSpider.
+
+ * heap/MarkedBlock.h:
+
+2011-07-31 Filip Pizlo <[email protected]>
+
DFG non-speculative JIT does not optimize PutByVal
https://bugs.webkit.org/show_bug.cgi?id=65424
Modified: trunk/Source/_javascript_Core/heap/MarkedBlock.h (92091 => 92092)
--- trunk/Source/_javascript_Core/heap/MarkedBlock.h 2011-07-31 23:17:24 UTC (rev 92091)
+++ trunk/Source/_javascript_Core/heap/MarkedBlock.h 2011-07-31 23:48:27 UTC (rev 92092)
@@ -42,7 +42,9 @@
class MarkedBlock : public DoublyLinkedListNode<MarkedBlock> {
friend class WTF::DoublyLinkedListNode<MarkedBlock>;
public:
- static const size_t atomSize = sizeof(double); // Ensures natural alignment for all built-in types.
+ // Ensure natural alignment for native types whilst recognizing that the smallest
+ // object the heap will commonly allocate is four words.
+ static const size_t atomSize = 4 * sizeof(void*);
static const size_t blockSize = 16 * KB;
static const size_t atomsPerBlock = blockSize / atomSize; // ~1.5% overhead
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