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

[Andi Kleen]

On Fri, Oct 12, 2012 at 02:54:54PM +0000, Ma, Ling wrote:
> > If you can't test the CPUs who run this code I think it's safer if you
> > add a new variant for Atom, not change the existing well tested code.
> > Otherwise you risk performance regressions on these older CPUs.
> 
> I found one older machine, and tested the code on it, the results between them are almost the same as below(attached cpu info).

Was that a P4 (family 15)? 

Those were the main users. There were a few others, but they are obscure
(early steppings of K8) 

-Andi


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ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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