Changeset 129586 in webkit for trunk/Source/JavaScriptCore/heap/Heap.h

Timestamp:

Sep 25, 2012, 7:27:54 PM (13 years ago)

Author:

[email protected]

Message:

JSC should dump object size inference statistics
​https://bugs.webkit.org/show_bug.cgi?id=97618

Reviewed by Filip Pizlo.

Added an option to dump object size inference statistics.

To see statistics on live objects:

jsc --showHeapStatistics=1

To see cumulative statistics on all objects ever allocated:

jsc --showHeapStatistics=1 --objectsAreImmortal=1

(This is useful for showing GC churn caused by over-allocation.)

To support this second mode, I refactored Zombies to separate out their
immortality feature so I could reuse it.

• heap/Heap.cpp:

(JSC::MarkObject): Helper for making things immortal. We have to checked
for being zapped because blocks start out in this state.

(JSC::StorageStatistics): Gather statistics by walking the heap. Ignore
arrays and hash tables for now because they're not our focus. (We'll
remove these exceptions in future.)

(JSC::Heap::collect): Moved zombify to the end so it wouldn't interfere
with statistics gathering.

(JSC::Heap::showStatistics):
(JSC::Heap::markAllObjects): Factored out helper, so statistics could
take advantage of immortal objects.

(Zombify): Don't mark immortal objects -- that's another class's job now.

(JSC::Zombify::operator()):
(JSC::Heap::zombifyDeadObjects): Take advantage of forEachDeadCell instead
of rolling our own.

• heap/Heap.h:

(Heap):

• heap/MarkedSpace.h:

(MarkedSpace):
(JSC::MarkedSpace::forEachDeadCell): Added, so clients don't have to do
the iteration logic themselves.

• runtime/Options.cpp:

(JSC::Options::initialize):

• runtime/Options.h: New options, listed above. Make sure to initialize

based on environment variable first, so we can override with specific settings.

File:

• trunk/Source/JavaScriptCore/heap/Heap.h (modified) (2 diffs)

trunk/Source/JavaScriptCore/heap/Heap.h

@@ -146 +146 @@
         JS_EXPORT_PRIVATE PassOwnPtr<TypeCountSet> protectedObjectTypeCounts();
         JS_EXPORT_PRIVATE PassOwnPtr<TypeCountSet> objectTypeCounts();
+        void showStatistics();
 
         void pushTempSortVector(Vector<ValueStringPair>*);
@@ -206 +207 @@
         void deleteUnmarkedCompiledCode();
         void zombifyDeadObjects();
- 
+        void markDeadObjects();
+
         RegisterFile& registerFile();
         BlockAllocator& blockAllocator();