Re: [PATCH RFC] [X86] performance improvement for memcpy_64.S by fast string.

H. Peter Anvin
2009-11-09T16:41:53Z

On 11/09/2009 01:26 AM, Andi Kleen wrote:
> "H. Peter Anvin" <hpa@zytor.com> writes:
>>
>> 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
>
> The issue is Core 2.
>
> P4 uses a different path, and Core 1 doesn't use the 64bit code.
>

Ling's numbers didn't seem to show a significant slowdown on Core 2 (it
was something like 0.95x baseline in the worst case, and most of the
cases were positive) so Core 2 doesn't seem to have a problem.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.