Messages in this thread | | | Date | Sat, 21 Feb 2015 19:34:55 +0100 | From | Ingo Molnar <> | Subject | Re: [RFC PATCH] x86, fpu: Use eagerfpu by default on all CPUs |
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* Borislav Petkov <bp@alien8.de> wrote:
> plain 3.19: > > 234.681331200 seconds time elapsed ( +- 0.15% ) > > eagerfpu=ENABLE > > 234.066525648 seconds time elapsed ( +- 0.19% )
hm, a win of more than 600 milliseconds - more than I'd have expected.
I really want to believe this, but I worry about the systematic boot-to-boot noise though, which cannot be eliminated via --repeat 10.
Would it be possible to add a simple runtime debug switch to switch between the two FPU modes dynamically via a sysctl?
It should not crash tasks I think if it's flipped around on a reasonably idle system, so should allow much better apples-to-apples comparisons with the same kind of page cache layout, etc.
Thanks,
Ingo
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