Re: [PATCH RFC 2/2] [x86] Optimize copy_page by re-arranginginstruction sequence and saving register

[Borislav Petkov]

On Fri, Oct 12, 2012 at 05:02:57PM -0400, George Spelvin wrote:
> Here are some Phenom results for that benchmark.  The average time
> increases from 700 to 760 cycles (+8.6%).

I was afraid something like that would show up.

Btw, in looking at this more and IINM, we use the REP MOVSQ version on
AMD anyway because of X86_FEATURE_REP_GOOD being set on some K8 and
everything from F10h on.

So, actually this Âbenchmark should be comparing the REP MOVSQ case too
and the changes to the unrolled copy_page shouldn't concern AMD boxes
actually...

Hmm.

-- 
Regards/Gruss,
    Boris.
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