Bug 144585

Summary:

Optimize WeakBlock's "reap" and "visit" operations.

Product:

WebKit

Reporter:

Andreas Kling <kling>

Component:

JavaScriptCore

Assignee:

Andreas Kling <kling>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

ggaren, kling, mhahnenb

Priority:

Keywords:

Performance

Version:

528+ (Nightly build)

Hardware:

Unspecified

OS:

Unspecified

Attachments:

Description	Flags
Patch idea	ggaren: review+

Description Andreas Kling 2015-05-04 10:20:44 PDT

WeakBlock's reap() and visit() could be a lot faster if they stopped doing so many paranoid address checks. Have patch, will post.

Comment 1 Andreas Kling 2015-05-04 10:21:38 PDT

Created attachment 252319 [details]
Patch idea

Comment 2 Geoffrey Garen 2015-05-04 10:46:01 PDT

Comment on attachment 252319 [details]
Patch idea

View in context: https://bugs.webkit.org/attachment.cgi?id=252319&action=review

r=me

> Source/JavaScriptCore/heap/MarkedBlock.h:415
> +    inline bool MarkedBlock::isLiveForWeakBlockScan(const JSCell* cell)

Let's call this isMarkedOrNewlyAllocated, and have isLive call it. That way, the MarkedBlock class is not responsible for promising that it's right to call this during weak block scan. It's only responsible for providing the answer that it knows.

> Source/JavaScriptCore/heap/WeakBlock.h:74
> +    void didDetachFromMarkedBlock() { m_markedBlock = nullptr; }

I think we usually call this "disconnectMarkedBlock".

Comment 3 Andreas Kling 2015-05-04 13:43:30 PDT

Committed r183769: <http://trac.webkit.org/changeset/183769>

Comment 4 Andreas Kling 2015-05-05 00:26:27 PDT

mac-mavericks perf bot says this was a 3.2% progression on Dromaeo/dom-modify :)