Messages in this thread | | | Date | Fri, 12 Oct 2012 17:14:10 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH RFC 2/2] [x86] Optimize copy_page by re-arranging instruction sequence and saving register |
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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
-- ak@linux.intel.com -- Speaking for myself only.
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