Performance: Optimize Dromaeo/dom-query.html by caching NodeRareData on Document

• Component: DOM
• Status: RESOLVED FIXED

[Kentaro Hara]

document.getElementsByClassName(), document.getElementsByTagName() and document.getElementsByName() are considered to be frequently used in the real world. Dromaeo/dom-query.html is also testing the performance of the three methods.

We can optimize the performance by caching a pointer to NodeRareData on Document.

[Kentaro Hara]

Created attachment 149721 [details]
Patch

[Kentaro Hara]

Created attachment 149856 [details]
Patch

[Ryosuke Niwa]

Comment on attachment 149856 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=149856&action=review

This seems like a good optimization. Make sure we're getting the same benefit for ElementRareData as things like document.images, document.all, etc... are all hanging out off ElementRareData as well.

> Source/WebCore/dom/Document.h:437
> +    NodeRareData* rareData() const { return m_rareData; };
> +    void setRareData(NodeRareData*);

Not sure if it's such a good idea to overload Node's rareData().

> Source/WebCore/dom/Node.cpp:500
> +        NodeRareData* data = static_cast<Document*>(this)->rareData();

We should probably declare a Document* local variable.

[Kentaro Hara]

Comment on attachment 149856 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=149856&action=review

>> Source/WebCore/dom/Document.h:437
>> +    void setRareData(NodeRareData*);
> 
> Not sure if it's such a good idea to overload Node's rareData().

What is your suggestion? (I thought that in IRC you suggested to rename cachedRareData() to rareData().)

>> Source/WebCore/dom/Node.cpp:500
>> +        NodeRareData* data = static_cast<Document*>(this)->rareData();
> 
> We should probably declare a Document* local variable.

Will fix.

[Kentaro Hara]

Created attachment 149865 [details]
patch for landing

[WebKit Review Bot]

Comment on attachment 149865 [details]
patch for landing

Clearing flags on attachment: 149865

Committed r121412: <http://trac.webkit.org/changeset/121412>