Bug 32505 - in-browser SunSpider suffers excessive penalty under power management
Summary: in-browser SunSpider suffers excessive penalty under power management
Alias: None
Product: WebKit
Classification: Unclassified
Component: Tools / Tests (show other bugs)
Version: 528+ (Nightly build)
Hardware: PC OS X 10.5
: P2 Normal
Assignee: Maciej Stachowiak
Depends on:
Reported: 2009-12-14 00:25 PST by Maciej Stachowiak
Modified: 2009-12-14 19:27 PST (History)
2 users (show)

See Also:

experimental patch (3.27 KB, patch)
2009-12-14 16:23 PST, Maciej Stachowiak
no flags Details | Formatted Diff | Diff
Patch (7.06 KB, patch)
2009-12-14 19:12 PST, Maciej Stachowiak
sam: review+
Details | Formatted Diff | Diff

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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):

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]
Comment 4 Maciej Stachowiak 2009-12-14 19:27:49 PST
Committed r52128: <http://trac.webkit.org/changeset/52128>