Adding freelist statistics to blink gc dump provider.

Source/platform/heap/Heap.cpp

Index: Source/platform/heap/Heap.cpp
diff --git a/Source/platform/heap/Heap.cpp b/Source/platform/heap/Heap.cpp
index d6c57cb4422785de3554b671e96c0070ef35d551..23509771c2442e42141e91334c5b28da6f9303d0 100644
--- a/Source/platform/heap/Heap.cpp
+++ b/Source/platform/heap/Heap.cpp
@@ -519,11 +519,9 @@ NormalPageHeap::NormalPageHeap(ThreadState* state, int index)
     , m_remainingAllocationSize(0)
     , m_lastRemainingAllocationSize(0)
     , m_promptlyFreedSize(0)
-#if ENABLE(GC_PROFILING)
     , m_cumulativeAllocationSize(0)
     , m_allocationCount(0)
     , m_inlineAllocationCount(0)
-#endif
 {
     clearFreeLists();
 }
@@ -562,6 +560,18 @@ bool NormalPageHeap::pagesToBeSweptContains(Address address)
 }
 #endif
 
+void NormalPageHeap::takeFreelistSnapshot(String dumpName)
+{
+    dumpName.append("/buckets");
+    WebMemoryAllocatorDump* allocatorDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpName);
+    allocatorDump->AddScalar("cumulative_allocation_size", "bytes", m_cumulativeAllocationSize);
+    allocatorDump->AddScalarF("inline_allocation_rate", static_cast<double>(m_inlineAllocationCount) / m_allocationCount);
+    allocatorDump->AddScalar("inline_allocation_count", "objects", m_inlineAllocationCount);
+    allocatorDump->AddScalar("allocation_count", "objects", m_allocationCount);
+
+    m_freeList.takeSnapshot(dumpName);
+}
+
 #if ENABLE(GC_PROFILING)
 void NormalPageHeap::snapshotFreeList(TracedValue& json)
 {
@@ -1120,6 +1130,24 @@ int FreeList::bucketIndexForSize(size_t size)
     return index;
 }
 
+void FreeList::takeSnapshot(const String& dumpBaseName)
+{
+    for (size_t i = 0; i < blinkPageSizeLog2; ++i) {
+        size_t entryCount = 0;
+        size_t freeSize = 0;
+        for (FreeListEntry* entry = m_freeLists[i]; entry; entry = entry->next()) {
+            ++entryCount;
+            freeSize += entry->size();
+        }
+
+        String dumpName = dumpBaseName.isolatedCopy();

[haraken, 2015/06/23 05:38:58]

Shall we pass in a String to takeSnapshot and avoid calling isolatedCopy?

[ssid, 2015/06/23 06:03:39]

hm, This is inside the for loop. I can't find a better way to do string append.
Do you have any other suggestions?

[haraken, 2015/06/23 06:24:24]

For string append, we're encouraged to use StringBuilder.

[ssid, 2015/06/23 07:39:56]

Sorry, i just realized it has a + operator, thought it looks cleaner. If you
still feel I should use StringBuilder, I will change it.

+        dumpName.append(String::format("/bucket_%lu", static_cast<unsigned long>(i)));

[haraken, 2015/06/23 05:38:58]

It would be more informative to use 2^i instead of i, since the bucket i
contains free slots of size [2^i, 2^(i+1)).

[ssid, 2015/06/23 07:39:56]

Done.

+        WebMemoryAllocatorDump* bucketDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpName);
+        bucketDump->AddScalar("freelist_entry_count", "objects", entryCount);
+        bucketDump->AddScalar("free_size", "bytes", freeSize);
+    }
+}
+
 #if ENABLE(GC_PROFILING)
 void FreeList::getFreeSizeStats(PerBucketFreeListStats bucketStats[], size_t& totalFreeSize) const
 {
@@ -1453,7 +1481,7 @@ void NormalPage::markOrphaned()
 
 void NormalPage::takeSnapshot(String dumpName, size_t pageIndex)
 {
-    dumpName.append(String::format("/page_%lu", static_cast<unsigned long>(pageIndex)));
+    dumpName.append(String::format("/pages/page_%lu", static_cast<unsigned long>(pageIndex)));
     WebMemoryAllocatorDump* pageDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpName);
 
     HeapObjectHeader* header = nullptr;
@@ -1662,7 +1690,7 @@ void LargeObjectPage::markOrphaned()
 
 void LargeObjectPage::takeSnapshot(String dumpName, size_t pageIndex)
 {
-    dumpName.append(String::format("/page_%lu", static_cast<unsigned long>(pageIndex)));
+    dumpName.append(String::format("/pages/page_%lu", static_cast<unsigned long>(pageIndex)));
     WebMemoryAllocatorDump* pageDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpName);
 
     size_t liveSize = 0;