Bug 111522 - Autoreleased cached pages slow down the PLT by 2%
Summary: Autoreleased cached pages slow down the PLT by 2%
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: New Bugs (show other bugs)
Version: 528+ (Nightly build)
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Geoffrey Garen
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2013-03-05 22:08 PST by Geoffrey Garen
Modified: 2013-03-15 21:30 PDT (History)
3 users (show)

See Also:

Attachments
Patch (1.11 KB, patch)
2013-03-05 22:10 PST, Geoffrey Garen 		fpizlo: review+
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Description Geoffrey Garen 2013-03-05 22:08:38 PST 
Autoreleased cached pages slow down the PLT by 2%
Comment 1 Geoffrey Garen 2013-03-05 22:10:28 PST 
Created attachment 191652 [details]
Patch
Comment 2 Geoffrey Garen 2013-03-05 22:55:54 PST 
Committed r144884: <http://trac.webkit.org/changeset/144884>
Comment 3 Darin Adler 2013-03-07 09:23:30 PST 
What were we getting by autoreleasing? I would trust this patch more if the change log stated what changed between the time we added it and now when we are removing it.
Comment 4 Geoffrey Garen 2013-03-07 11:48:38 PST 
> What were we getting by autoreleasing?

Originally, it was a hack to avoid doing any document tear-down while running PLT1.

> I would trust this patch more if the change log stated what changed between the time we added it and now when we are removing it.

I can't say for sure what changed, but if I had to speculate, I'd say this:

(1) Web pages are large enough these days that eagerly reclaiming memory can be a cache locality win.

(2) Garbage collection is a more robust way to gain whatever advantage is attributable to lazy tear-down, especially since most pages don't make it into the page cache.

(3) PLT3 is a more representative benchmark than PLT1.
Comment 5 Simon Fraser (smfr) 2013-03-15 21:30:44 PDT 
This caused bug 112205.