Bug 184499
| Summary: | MotionMark gives wrong results after spectre mitigations of performance.now() | ||
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| Product: | WebKit | Reporter: | Carlos Alberto Lopez Perez <clopez> |
| Component: | Tools / Tests | Assignee: | Nobody <webkit-unassigned> |
| Status: | RESOLVED INVALID | ||
| Severity: | Normal | CC: | ap, jonlee, lforschler, rniwa, sabouhallawa, simon.fraser |
| Priority: | P2 | ||
| Version: | WebKit Nightly Build | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
Carlos Alberto Lopez Perez
After spectre mitigations performance.now() not longer a hight resolution timer. This causes that the default settings of motionmark to give wrong results.
Motion mark supports 3 methods to measure performance as you can see here at the bottom right http://browserbench.org/MotionMark/developer.html
The default should be changed from performance.now() to one of the other methods.
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Simon Fraser (smfr)
perf.now() and rAF timestamp should be quantized the same way, and I think Date.now() will also be.
Carlos Alberto Lopez Perez
(In reply to Simon Fraser (smfr) from comment #1)
> perf.now() and rAF timestamp should be quantized the same way, and I think
> Date.now() will also be.
That makes sense, actually.
I have been testing motionmark with WPE trunk and I have been getting sometimes some weird results with the default settings (like 1 points on some tests with a +-3000% percent of variance).
So, at first I thought it could be related to the spectre mitigations of performance.now() because I couldn't reproduce with the other methods of the benchmark like rAF.
But I'm not able to reproduce this with a webkit build of last trunk on Mac. So it should be something else...
I'm closing this as invalid, then.
Thanks for the comments.