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

H. Peter Anvin
2009-11-09T22:37:18Z

On 11/09/2009 10:54 AM, Andi Kleen wrote:
>> 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.
>
> I ran quite a lot of micro benchmarks with various alignments and sizes
> the 'q' variant was not always a win. I haven't checked that particular
> version though.

Well, if you have concrete information about what the problem cases are,
then please provide it. If you don't, but have a hunch where these
potential problems may lie, then please indicate what they might be.
Otherwise, there isn't any actionable information here.

-hpa