Messages in this thread | | | Date | Thu, 9 Sep 2021 11:39:40 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH] perf: optimize clear page in Intel specified model with movq instruction |
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On Thu, Sep 09, 2021 at 04:45:51PM +0800, Jinhua Wu wrote: > Clear page is the most time-consuming procedure in page fault handling. > Kernel use fast-string instruction to clear page. We found that in specified > Intel model such as CPX and ICX, the movq instruction perform much better > than fast-string instruction when corresponding page is not in cache. > But when the page is in cache, fast string perform better. We show the test > result in the following:
What you should do is show the extensive tests you've run with real-world benchmarks where you really can show 40% performance improvement.
Also, the static branch "approach" you're using ain't gonna happen. If anything, another X86_FEATURE_* bit.
Good luck.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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