Bug 43257

Summary: SunSpider's Math.random makes it unpredictable
Product: WebKit Reporter: Paul Biggar <pbiggar>
Component: Tools / TestsAssignee: Nobody <webkit-unassigned>
Status: UNCONFIRMED    
Severity: Normal CC: eric, ggaren, mjs, oliver
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: PC   
OS: OS X 10.5   
Bug Depends on:    
Bug Blocks: 43253    
Attachments:
Description Flags
Makes math.random deterministic
none
Make math.random deterministic (sans upvars) eric: review-

Paul Biggar
Reported 2010-07-30 09:37:25 PDT
Sunspider calls Math.random in quite a few places, accounting for a measurable increase in run-time variance (https://bugzilla.mozilla.org/show_bug.cgi?id=580532#c24): sunspider-0.9.1/string-validate-input.js sunspider-0.9/string-base64.js sunspider-0.9/string-validate-input.js v8-v4/v8-crypto.js v8-v4/v8-earley-boyer.js v8-v4/v8-splay.js In v8's test harness, Math.random is replaced by a deterministic function. However, Sunspider skips the v8 test harness.
Attachments
Makes math.random deterministic (1.61 KB, patch)
2010-08-06 13:56 PDT, Paul Biggar 		no flags
DetailsFormatted DiffDiff
Make math.random deterministic (sans upvars) (1.65 KB, patch)
2010-08-07 04:20 PDT, Paul Biggar 		eric: review-
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Paul Biggar
Comment 1 2010-08-06 13:56:55 PDT
Created attachment 63758 [details] Makes math.random deterministic This replaces Math.random with v8's deterministic version. You'll need patch -p4 to apply this.
Paul Biggar
Comment 2 2010-08-07 04:20:12 PDT
Created attachment 63814 [details] Make math.random deterministic (sans upvars) The upvars on the old patch change the characteristics of the test. This uses a plain old global variable instead.
Paul Biggar
Comment 3 2010-08-13 03:08:25 PDT
Ping? This is the simplest change to approve of all the blockers to bug 43253.
Eric Seidel (no email)
Comment 4 2011-06-02 08:07:41 PDT
Comment on attachment 63814 [details] Make math.random deterministic (sans upvars) Needs a ChangeLog. Sounds like a good change to me, but I am not really a decision maker for SunSpider. Then again, it seems sunspider hasn't been touche din years...
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