Bug 140762

Summary: EdenCollections unnecessarily visit SmallStrings
Product: WebKit Reporter: Mark Hahnenberg <mhahnenb>
Component: JavaScriptCoreAssignee: Mark Hahnenberg <mhahnenb>
Status: RESOLVED FIXED    
Severity: Normal CC: commit-queue, kling
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on:    
Bug Blocks: 140774    
Attachments:
Description Flags
Patch
none
GC logs before
none
GC logs after none

Description Mark Hahnenberg 2015-01-21 23:17:32 PST 
Once SmallStrings have been marked, they no longer need to be visited during EdenCollections. I noticed they were consuming a non-trivial amount of total EdenCollection time, so let's fix it!
Comment 1 Mark Hahnenberg 2015-01-21 23:51:54 PST 
Created attachment 245125 [details]
Patch
Comment 2 Mark Hahnenberg 2015-01-21 23:53:56 PST 
Created attachment 245126 [details]
GC logs before
Comment 3 Mark Hahnenberg 2015-01-21 23:54:12 PST 
Created attachment 245127 [details]
GC logs after
Comment 4 Mark Hahnenberg 2015-01-21 23:55:02 PST 
Attached GC timing logs before and after the change. Time spent in VisitSmallStrings is down significantly, but it didn't seem to affect the overall Eden time as much as I'd expect.
Comment 5 Geoffrey Garen 2015-01-22 09:09:48 PST 
Comment on attachment 245125 [details]
Patch

r=me
Comment 6 WebKit Commit Bot 2015-01-22 23:04:02 PST 
Comment on attachment 245125 [details]
Patch

Clearing flags on attachment: 245125

Committed r178984: <http://trac.webkit.org/changeset/178984>
Comment 7 WebKit Commit Bot 2015-01-22 23:04:08 PST 
All reviewed patches have been landed.  Closing bug.
Comment 8 Andreas Kling 2015-03-16 13:57:01 PDT 
(In reply to comment #4)
> Attached GC timing logs before and after the change. Time spent in
> VisitSmallStrings is down significantly, but it didn't seem to affect the
> overall Eden time as much as I'd expect.

Still, that's a really impressive improvement! Thanks for making this change, Mark. :)