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rr-debugger / rr

Record and Replay Framework
http://rr-project.org/
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Investigate why sunspider overhead is higher in-browser vs. jsshell #836

Open joneschrisg opened 10 years ago

joneschrisg commented 10 years ago

We saw in #10 that, before meliorizations, rr record overhead was about 2.2x for sunspider in-browser, and about 1.9x in jsshell. After meliorizations, we got it down to 1.2x for jsshell but I didn't re-measure in-browser.

On my bare metal x64 machine, I'm seeing ~1.4x overhead in-browser. It's more complicated to measure jsshell overhead, but I expect it to be no worse than 1.2x. So we're seeing ballpark the same difference in overhead.

It'd be interesting to see why the difference is this big. 1.4x is palatable for 1.0, so my inclination is to punt this for now. (This also might end up requiring analysis from someone with serious gecko or SM chops, which I don't have.)

rocallahan commented 10 years ago

Yes, let's not worry about this for now.