[webkit-changes] [137328] trunk/Source/WebKit2

Tue, 11 Dec 2012 09:42:07 -0800

Title: [137328] trunk/Source/WebKit2
Revision
137328
Author
[email protected]
Date
2012-12-11 09:41:27 -0800 (Tue, 11 Dec 2012)

Log Message

CoreIPC: ArgumentEncoder should have an inline buffer.
<http://webkit.org/b/104622>

Reviewed by Anders Carlsson.

Add a 4K inline buffer to CoreIPC::ArgumentEncoder to avoid malloc/free churn.
It was dominating the transient allocations graph in Instruments.

* Platform/CoreIPC/ArgumentEncoder.cpp:
(CoreIPC::ArgumentEncoder::ArgumentEncoder):
(CoreIPC::ArgumentEncoder::grow):
* Platform/CoreIPC/ArgumentEncoder.h:
(CoreIPC::ArgumentEncoder::buffer):
(ArgumentEncoder):
(CoreIPC::ArgumentEncoder::usesInlineBuffer):

Modified Paths

Diff

Modified: trunk/Source/WebKit2/ChangeLog (137327 => 137328)


--- trunk/Source/WebKit2/ChangeLog	2012-12-11 17:38:28 UTC (rev 137327)
+++ trunk/Source/WebKit2/ChangeLog	2012-12-11 17:41:27 UTC (rev 137328)
@@ -1,3 +1,21 @@
+2012-12-11  Andreas Kling  <[email protected]>
+
+        CoreIPC: ArgumentEncoder should have an inline buffer.
+        <http://webkit.org/b/104622>
+
+        Reviewed by Anders Carlsson.
+
+        Add a 4K inline buffer to CoreIPC::ArgumentEncoder to avoid malloc/free churn.
+        It was dominating the transient allocations graph in Instruments.
+
+        * Platform/CoreIPC/ArgumentEncoder.cpp:
+        (CoreIPC::ArgumentEncoder::ArgumentEncoder):
+        (CoreIPC::ArgumentEncoder::grow):
+        * Platform/CoreIPC/ArgumentEncoder.h:
+        (CoreIPC::ArgumentEncoder::buffer):
+        (ArgumentEncoder):
+        (CoreIPC::ArgumentEncoder::usesInlineBuffer):
+
 2012-12-11  Mike West  <[email protected]>
 
         Web Inspector: ConsoleTypes should not expose MessageType - it should be private to inspector.

Modified: trunk/Source/WebKit2/Platform/CoreIPC/ArgumentEncoder.cpp (137327 => 137328)


--- trunk/Source/WebKit2/Platform/CoreIPC/ArgumentEncoder.cpp	2012-12-11 17:38:28 UTC (rev 137327)
+++ trunk/Source/WebKit2/Platform/CoreIPC/ArgumentEncoder.cpp	2012-12-11 17:41:27 UTC (rev 137328)
@@ -39,9 +39,8 @@
 
 ArgumentEncoder::ArgumentEncoder()
     : m_buffer(0)
-    , m_bufferPointer(0)
     , m_bufferSize(0)
-    , m_bufferCapacity(0)
+    , m_bufferCapacity(inlineBufferSize)
 {
 }
 
@@ -68,27 +67,31 @@
     
     if (alignedSize + size > m_bufferCapacity) {
         size_t newCapacity = std::max(alignedSize + size, std::max(static_cast<size_t>(32), m_bufferCapacity + m_bufferCapacity / 4 + 1));
-        // Use system malloc / realloc instead of fastMalloc due to 
-        // fastMalloc using MADV_FREE_REUSABLE which doesn't work with
-        // mach messages with OOL message and MACH_MSG_VIRTUAL_COPY.
-        // System malloc also calls madvise(MADV_FREE_REUSABLE) but after first
-        // checking via madvise(CAN_REUSE) that it will succeed. Should this
-        // behavior change we'll need to revisit this.
-        if (!m_buffer)
-            m_buffer = static_cast<uint8_t*>(malloc(newCapacity));
-        else
-            m_buffer = static_cast<uint8_t*>(realloc(m_buffer, newCapacity));
 
-        if (!m_buffer)
-            CRASH();
+        if (newCapacity > inlineBufferSize) {
+            // Use system malloc / realloc instead of fastMalloc due to
+            // fastMalloc using MADV_FREE_REUSABLE which doesn't work with
+            // mach messages with OOL message and MACH_MSG_VIRTUAL_COPY.
+            // System malloc also calls madvise(MADV_FREE_REUSABLE) but after first
+            // checking via madvise(CAN_REUSE) that it will succeed. Should this
+            // behavior change we'll need to revisit this.
+            if (!m_buffer)
+                m_buffer = static_cast<uint8_t*>(malloc(newCapacity));
+            else
+                m_buffer = static_cast<uint8_t*>(realloc(m_buffer, newCapacity));
 
+            if (!m_buffer)
+                CRASH();
+
+            if (usesInlineBuffer())
+                memcpy(m_buffer, m_inlineBuffer, m_bufferCapacity);
+        }
+
         m_bufferCapacity = newCapacity;        
     }
 
     m_bufferSize = alignedSize + size;
-    m_bufferPointer = m_buffer + alignedSize + size;
-    
-    return m_buffer + alignedSize;
+    return buffer() + alignedSize;
 }
 
 void ArgumentEncoder::encodeFixedLengthData(const uint8_t* data, size_t size, unsigned alignment)

Modified: trunk/Source/WebKit2/Platform/CoreIPC/ArgumentEncoder.h (137327 => 137328)


--- trunk/Source/WebKit2/Platform/CoreIPC/ArgumentEncoder.h	2012-12-11 17:38:28 UTC (rev 137327)
+++ trunk/Source/WebKit2/Platform/CoreIPC/ArgumentEncoder.h	2012-12-11 17:41:27 UTC (rev 137328)
@@ -98,7 +98,7 @@
         return *this;
     }
 
-    uint8_t* buffer() const { return m_buffer; }
+    uint8_t* buffer() { return usesInlineBuffer() ? m_inlineBuffer : m_buffer; }
     size_t bufferSize() const { return m_bufferSize; }
 
     void addAttachment(const Attachment&);
@@ -108,15 +108,18 @@
     ArgumentEncoder();
 
 private:
+    static const size_t inlineBufferSize = 4096;
+    bool usesInlineBuffer() const { return m_bufferCapacity <= inlineBufferSize; }
     uint8_t* grow(unsigned alignment, size_t size);
     
     uint8_t* m_buffer;
-    uint8_t* m_bufferPointer;
     
     size_t m_bufferSize;
     size_t m_bufferCapacity;
 
     Vector<Attachment> m_attachments;
+
+    uint8_t m_inlineBuffer[inlineBufferSize];
 };
 
 } // namespace CoreIPC

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