Re: [lkp] [x86/hweight] 65ea11ec6a: will-it-scale.per_process_ops 9.3% improvement

From: H. Peter Anvin
Date: Tue Aug 16 2016 - 19:11:38 EST


On August 16, 2016 10:16:35 AM PDT, Borislav Petkov <bp@xxxxxxx> wrote:
>On Tue, Aug 16, 2016 at 09:59:00AM -0700, H. Peter Anvin wrote:
>> Dang...
>
>Isn't 9.3% improvement a good thing(tm) ?

Yes, it's huge. The only explanation I could imagine is that scrambling %rdi caused the scheduler to do completely the wrong thing.
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