[V8][Performance] Optimize createTextNode(), createElement(), cloneNode(), etc

https://bugs.webkit.org/show_bug.cgi?id=82201

Reviewed by Adam Barth.

This patch improves performance of createTextNode() by 13%, createElement() by 14%,
and cloneNode() by 16%. Similar performance improvement will be observed in
DOM methods that create a new object every time.

Performance test: https://bugs.webkit.org/attachment.cgi?id=133799

The performance test results are as follows. Since the performance of V8's GC is
really unstable, the average of measured times makes no sense in Chromium.
Instead, let us focus on the median. I believe that this performance
improvement has impact on Dromaeo, but we cannot observe the improvement
due to the unsteadiness of V8's GC, as shown below.

Chromium/V8/Linux (without the patch):
createTextNode : median=277ms (mean=460.88ms, min=270ms, max=3381ms)
createElement : median=379ms (mean=637.52ms, min=372ms, max=3022ms)
cloneNode : median=369ms (mean=581.72ms, min=363ms, max=3050ms)
Dromaeo/dom-modify/createElement: 439.17runs/s +-31.60% (<--- pretty noisy)
Dromaeo/dom-modify/createTextNode: 287.71runs/s +-28.39% (<--- pretty noisy)
Dromaeo/dom-modify/cloneNode: 174.62runs/s +-25.68% (<--- pretty noisy)

Chromium/V8/Linux (with the patch):
createTextNode : median=240ms (mean=411.12ms, min=237ms, max=2965ms)
createElement : median=325ms (mean=585.30ms, min=317ms, max=2984ms)
cloneNode : median=310ms (mean=522.48ms, min=302ms, max=2988ms)
Dromaeo/dom-modify/createElement: 507.15runs/s +-36.00% (<--- pretty noisy)
Dromaeo/dom-modify/createTextNode: 251.01runs/s +-6.57%
Dromaeo/dom-modify/cloneNode: 177.85runs/s +-28.74% (<--- pretty noisy)

Chromium/V8/Mac (without the patch):
createTextNode : median=317ms (mean=439.08ms, min=303ms, max=3126ms)
createElement : median=403ms (mean=695.70ms, min=398ms, max=5615ms)
cloneNode : median=384ms (mean=577.96ms, min=372ms, max=5313ms)
Dromaeo/dom-modify/createElement: 493.89runs/s +-28.32% (<--- pretty noisy)
Dromaeo/dom-modify/createTextNode: 279.66runs/s +-1.91%
Dromaeo/dom-modify/cloneNode: 173.06runs/s +-24.41% (<--- pretty noisy)

Chromium/V8/Mac (with the patch):
createTextNode : median=277ms (mean=460.88ms, min=270ms, max=3381ms)
createElement : median=379ms (mean=637.52ms, min=372ms, max=3022ms)
cloneNode : median=369ms (mean=581.72ms, min=363ms, max=3050ms)
Dromaeo/dom-modify/createElement: 510.47runs/s +-28.13% (<--- pretty noisy)
Dromaeo/dom-modify/createTextNode: 215.80runs/s +-20.99% (<--- pretty noisy)
Dromaeo/dom-modify/cloneNode: 174.41runs/s +-24.85% (<--- pretty noisy)

Safari/JavaScriptCore/Mac:
createTextNode : median=142ms (mean=141.04ms, min=110ms, max=168ms)
createElement : median=234ms (mean=245.74ms, min=219ms, max=305ms)
cloneNode : median=210ms (mean=213.36ms, min=204ms, max=284ms)
Dromaeo/dom-modify/createElement: 822.49runs/s +-1.69%
Dromaeo/dom-modify/createTextNode: 735.57runs/s +-0.91%
Dromaeo/dom-modify/cloneNode: 135.20runs/s +-4.13%

This patch makes the following two optimizations:

[1] If the currently running context is equal to the context that we are about to enter,
we do not call context->Enter().
[2] We do not create a Local handle of the context until we really need to enter the context.

* bindings/scripts/CodeGeneratorV8.pm:
(GenerateToV8Converters):
* bindings/v8/V8Proxy.cpp:
(WebCore::V8Proxy::persistentContext):
(WebCore):
* bindings/v8/V8Proxy.h:
(V8Proxy):

* WebCore/bindings/scripts/test/V8/V8TestActiveDOMObject.cpp: Updated run-bindings-tests results.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@112218 268f45cc-cd09-0410-ab3c-d52691b4dbfc

diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
index 4d460ed..268a5b9 100644 (file)
--- a/Source/WebCore/ChangeLog
+++ b/Source/WebCore/ChangeLog
@@ -1,3 +1,78 @@
+2012-03-27  Kentaro Hara  <haraken@chromium.org>
+
+        [V8][Performance] Optimize createTextNode(), createElement(), cloneNode(), etc
+        https://bugs.webkit.org/show_bug.cgi?id=82201
+
+        Reviewed by Adam Barth.
+
+        This patch improves performance of createTextNode() by 13%, createElement() by 14%,
+        and cloneNode() by 16%. Similar performance improvement will be observed in
+        DOM methods that create a new object every time.
+
+        Performance test: https://bugs.webkit.org/attachment.cgi?id=133799
+
+        The performance test results are as follows. Since the performance of V8's GC is
+        really unstable, the average of measured times makes no sense in Chromium.
+        Instead, let us focus on the median. I believe that this performance
+        improvement has impact on Dromaeo, but we cannot observe the improvement
+        due to the unsteadiness of V8's GC, as shown below.
+
+        Chromium/V8/Linux (without the patch):
+        createTextNode : median=277ms (mean=460.88ms, min=270ms, max=3381ms)
+        createElement : median=379ms (mean=637.52ms, min=372ms, max=3022ms)
+        cloneNode : median=369ms (mean=581.72ms, min=363ms, max=3050ms)
+        Dromaeo/dom-modify/createElement: 439.17runs/s +-31.60% (<--- pretty noisy)
+        Dromaeo/dom-modify/createTextNode: 287.71runs/s +-28.39% (<--- pretty noisy)
+        Dromaeo/dom-modify/cloneNode: 174.62runs/s +-25.68% (<--- pretty noisy)
+
+        Chromium/V8/Linux (with the patch):
+        createTextNode : median=240ms (mean=411.12ms, min=237ms, max=2965ms)
+        createElement : median=325ms (mean=585.30ms, min=317ms, max=2984ms)
+        cloneNode : median=310ms (mean=522.48ms, min=302ms, max=2988ms)
+        Dromaeo/dom-modify/createElement: 507.15runs/s +-36.00% (<--- pretty noisy)
+        Dromaeo/dom-modify/createTextNode: 251.01runs/s +-6.57%
+        Dromaeo/dom-modify/cloneNode: 177.85runs/s +-28.74% (<--- pretty noisy)
+
+        Chromium/V8/Mac (without the patch):
+        createTextNode : median=317ms (mean=439.08ms, min=303ms, max=3126ms)
+        createElement : median=403ms (mean=695.70ms, min=398ms, max=5615ms)
+        cloneNode : median=384ms (mean=577.96ms, min=372ms, max=5313ms)
+        Dromaeo/dom-modify/createElement: 493.89runs/s +-28.32% (<--- pretty noisy)
+        Dromaeo/dom-modify/createTextNode: 279.66runs/s +-1.91%
+        Dromaeo/dom-modify/cloneNode: 173.06runs/s +-24.41% (<--- pretty noisy)
+
+        Chromium/V8/Mac (with the patch):
+        createTextNode : median=277ms (mean=460.88ms, min=270ms, max=3381ms)
+        createElement : median=379ms (mean=637.52ms, min=372ms, max=3022ms)
+        cloneNode : median=369ms (mean=581.72ms, min=363ms, max=3050ms)
+        Dromaeo/dom-modify/createElement: 510.47runs/s +-28.13% (<--- pretty noisy)
+        Dromaeo/dom-modify/createTextNode: 215.80runs/s +-20.99% (<--- pretty noisy)
+        Dromaeo/dom-modify/cloneNode: 174.41runs/s +-24.85% (<--- pretty noisy)
+
+        Safari/JavaScriptCore/Mac:
+        createTextNode : median=142ms (mean=141.04ms, min=110ms, max=168ms)
+        createElement : median=234ms (mean=245.74ms, min=219ms, max=305ms)
+        cloneNode : median=210ms (mean=213.36ms, min=204ms, max=284ms)
+        Dromaeo/dom-modify/createElement: 822.49runs/s +-1.69%
+        Dromaeo/dom-modify/createTextNode: 735.57runs/s +-0.91%
+        Dromaeo/dom-modify/cloneNode: 135.20runs/s +-4.13%
+
+        This patch makes the following two optimizations:
+
+        [1] If the currently running context is equal to the context that we are about to enter,
+        we do not call context->Enter().
+        [2] We do not create a Local handle of the context until we really need to enter the context.
+
+        * bindings/scripts/CodeGeneratorV8.pm:
+        (GenerateToV8Converters):
+        * bindings/v8/V8Proxy.cpp:
+        (WebCore::V8Proxy::persistentContext):
+        (WebCore):
+        * bindings/v8/V8Proxy.h:
+        (V8Proxy):
+
+        * WebCore/bindings/scripts/test/V8/V8TestActiveDOMObject.cpp: Updated run-bindings-tests results.
+
 2012-03-27  Bill Budge  <bbudge@chromium.org>
 
         cross-origin XMLHttpRequest doesn't work with redirect

diff --git a/Source/WebCore/bindings/scripts/CodeGeneratorV8.pm b/Source/WebCore/bindings/scripts/CodeGeneratorV8.pm
index cb4e342..bdc3ac9 100644 (file)
--- a/Source/WebCore/bindings/scripts/CodeGeneratorV8.pm
+++ b/Source/WebCore/bindings/scripts/CodeGeneratorV8.pm
@@ -3144,13 +3144,15 @@ END
     if (IsNodeSubType($dataNode) || IsVisibleAcrossOrigins($dataNode)) {
         push(@implContent, <<END);
 
+    // Enter the node's context and create the wrapper in that context.
     v8::Handle<v8::Context> context;
-    if (proxy)
+    if (proxy && !proxy->matchesCurrentContext()) {
+        // For performance, we enter the context only if the currently running context
+        // is different from the context that we are about to enter.
         context = proxy->context();
-
-    // Enter the node's context and create the wrapper in that context.
-    if (!context.IsEmpty())
-        context->Enter();
+        if (!context.IsEmpty())
+            context->Enter();
+    }
 END
     }
 

diff --git a/Source/WebCore/bindings/scripts/test/V8/V8TestActiveDOMObject.cpp b/Source/WebCore/bindings/scripts/test/V8/V8TestActiveDOMObject.cpp
index 034bda6..a8291af 100644 (file)
--- a/Source/WebCore/bindings/scripts/test/V8/V8TestActiveDOMObject.cpp
+++ b/Source/WebCore/bindings/scripts/test/V8/V8TestActiveDOMObject.cpp
@@ -168,13 +168,15 @@ v8::Handle<v8::Object> V8TestActiveDOMObject::wrapSlow(PassRefPtr<TestActiveDOMO
             proxy->windowShell()->initContextIfNeeded();
     }
 
+    // Enter the node's context and create the wrapper in that context.
     v8::Handle<v8::Context> context;
-    if (proxy)
+    if (proxy && !proxy->matchesCurrentContext()) {
+        // For performance, we enter the context only if the currently running context
+        // is different from the context that we are about to enter.
         context = proxy->context();
-
-    // Enter the node's context and create the wrapper in that context.
-    if (!context.IsEmpty())
-        context->Enter();
+        if (!context.IsEmpty())
+            context->Enter();
+    }
     wrapper = V8DOMWrapper::instantiateV8Object(proxy, &info, impl.get());
     // Exit the node's context if it was entered.
     if (!context.IsEmpty())

diff --git a/Source/WebCore/bindings/v8/V8Proxy.cpp b/Source/WebCore/bindings/v8/V8Proxy.cpp
index d8a7d46..4266334 100644 (file)
--- a/Source/WebCore/bindings/v8/V8Proxy.cpp
+++ b/Source/WebCore/bindings/v8/V8Proxy.cpp
@@ -642,6 +642,20 @@ v8::Local<v8::Context> V8Proxy::mainWorldContext()
     return v8::Local<v8::Context>::New(windowShell()->context());
 }
 
+bool V8Proxy::matchesCurrentContext()
+{
+    v8::Handle<v8::Context> context;
+    if (V8IsolatedContext* isolatedContext = V8IsolatedContext::getEntered()) {
+        context = isolatedContext->sharedContext()->get();
+        if (m_frame != V8Proxy::retrieveFrame(context))
+            return false;
+    } else {
+        windowShell()->initContextIfNeeded();
+        context = windowShell()->context();
+    }
+    return context == context->GetCurrent();
+}
+
 v8::Local<v8::Context> V8Proxy::mainWorldContext(Frame* frame)
 {
     V8Proxy* proxy = retrieve(frame);

diff --git a/Source/WebCore/bindings/v8/V8Proxy.h b/Source/WebCore/bindings/v8/V8Proxy.h
index 5b7cce4..4afe3ba 100644 (file)
--- a/Source/WebCore/bindings/v8/V8Proxy.h
+++ b/Source/WebCore/bindings/v8/V8Proxy.h
@@ -243,6 +243,7 @@ namespace WebCore {
 
         v8::Local<v8::Context> context();
         v8::Local<v8::Context> mainWorldContext();
+        bool matchesCurrentContext();
 
         // FIXME: This should eventually take DOMWrapperWorld argument!
         V8DOMWindowShell* windowShell() const { return m_windowShell.get(); }