RESOLVED INVALID 184499
MotionMark gives wrong results after spectre mitigations of performance.now()
https://bugs.webkit.org/show_bug.cgi?id=184499
Summary MotionMark gives wrong results after spectre mitigations of performance.now()
Carlos Alberto Lopez Perez
Reported 2018-04-11 08:00:30 PDT
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.
Attachments
Simon Fraser (smfr)
Comment 1 2018-04-11 09:21:24 PDT
perf.now() and rAF timestamp should be quantized the same way, and I think Date.now() will also be.
Carlos Alberto Lopez Perez
Comment 2 2018-04-11 16:22:50 PDT
(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.
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