Bug 61306

Summary: Is the YARR begin characters optimization still a win?
Product: WebKit Reporter: Gavin Barraclough <barraclough>
Component: JavaScriptCoreAssignee: Gavin Barraclough <barraclough>
Status: RESOLVED FIXED    
Severity: Normal CC: ggaren, pvarga
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on:    
Bug Blocks: 45749, 61129    
Attachments:
Description Flags
The patch ggaren: review+

Description Gavin Barraclough 2011-05-23 14:09:50 PDT
It looks like the benefit of this optimization may have been lost since the BOL optimizations went in ('once through' flag).

Disabling this optimization seems to have no impact on SunSpider performance, and I measure a 2% win on v8 w/ YARR interpreter by disabling.

If disabling will simplify the code, fix bugs & improve performance, than that is what we should do.

Do we have evidence that this is still a win?
Comment 1 Gavin Barraclough 2011-05-23 16:34:52 PDT
Created attachment 94517 [details]
The patch
Comment 2 Geoffrey Garen 2011-05-23 17:02:15 PDT
Comment on attachment 94517 [details]
The patch

r=me
Comment 3 Gavin Barraclough 2011-05-23 17:10:24 PDT
Removing this optimization for now in r87109, open to re-landing if we can demonstrate a significant performance win.