Messages in this thread | | | Date | Sun, 08 Nov 2009 23:36:12 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH RFC] [X86] performance improvement for memcpy_64.S by fast string. |
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On 11/08/2009 11:24 PM, Ma, Ling wrote: > Hi All > > Today we run our benchmark on Core2 and Sandy Bridge: >
Hi Ling,
Thanks for doing that. Do you also have access to any older CPUs? I suspect that the CPUs that Andi are worried about are older CPUs like P4, K8 or Pentium M/Core 1. (Andi: please do clarify if you have additional information.)
My personal opinion is that if we can show no significant slowdown on P4, K8, P-M/Core 1, Core 2, and Nehalem then we can simply use this code unconditionally. If one of them is radically worse than baseline, then we have to do something conditional, which is a lot more complicated.
[Ingo, Thomas: do you agree?]
Thanks,
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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