Bug 111522

Summary: Autoreleased cached pages slow down the PLT by 2%
Product: WebKit Reporter: Geoffrey Garen <ggaren>
Component: New BugsAssignee: Geoffrey Garen <ggaren>
Status: RESOLVED FIXED    
Severity: Normal CC: darin, fpizlo, simon.fraser
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Patch fpizlo: review+

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.