Bug 32505

Summary: in-browser SunSpider suffers excessive penalty under power management
Product: WebKit Reporter: Maciej Stachowiak <mjs>
Component: Tools / TestsAssignee: Maciej Stachowiak <mjs>
Status: RESOLVED FIXED    
Severity: Normal CC: ap, seth.gaurav
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: PC   
OS: OS X 10.5   
Attachments:
Description Flags
experimental patch
none
Patch sam: review+

Description Maciej Stachowiak 2009-12-14 00:25:02 PST 
For systems with active power management that perform significant CPU stepping, in-browser SunSpider gives results that are surprisingly slower than what one would expect from a command-line run against the pure engine, in the case of particularly fast JavaScript engines on fast hardware. The reason for this is that SunSpider in-browser pauses for 500ms between tests, thus the CPU never properly ramps up to speed when the tests take only a few milliseconds each. It would be better to have a much shorter pause, say 10ms, but then the harness needs to be redesigned to prevent networking and progress indicators from unduly disturbing the results.
Comment 1 Maciej Stachowiak 2009-12-14 16:22:28 PST 
This issue was originally reported by Mike Belshe here (his point #3):

https://lists.webkit.org/pipermail/webkit-dev/2009-July/008723.html
Comment 2 Maciej Stachowiak 2009-12-14 16:23:08 PST 
Created attachment 44828 [details]
experimental patch
Comment 3 Maciej Stachowiak 2009-12-14 19:12:31 PST 
Created attachment 44833 [details]
Patch
Comment 4 Maciej Stachowiak 2009-12-14 19:27:49 PST 
Committed r52128: <http://trac.webkit.org/changeset/52128>