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Re: [PATCH RFC] Imporve 64bit memcpy performance for Haswell CPU with AVX instruction
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Ling Ma <ling dot ma dot program at gmail dot com>
- Cc: OndÅej BÃlka <neleai at seznam dot cz>, GNU C Library <libc-alpha at sourceware dot org>, Liubov Dmitrieva <liubov dot dmitrieva at gmail dot com>, yumkam at gmail dot com, Ling Ma <ling dot ml at alibaba-inc dot com>
- Date: Wed, 25 Jun 2014 08:16:58 -0700
- Subject: Re: [PATCH RFC] Imporve 64bit memcpy performance for Haswell CPU with AVX instruction
- Authentication-results: sourceware.org; auth=none
- References: <1398055946-4493-1-git-send-email-ling dot ma at alipay dot com> <CAOGi=dOQEbbkkzQGz-ZtQ0-WEHj2=hjmbstZXvZyLqycVy18Kg at mail dot gmail dot com> <20140515202213 dot GA20667 at domone dot podge> <CAOGi=dNbyxj+7gjwcpAVBxYB-MH9E7s=xi2nKwYXkDViasOZrA at mail dot gmail dot com> <CAMe9rOpC5-p7DV=xBfhUknkruz2-Ek+Bpzm+ycZiKdXtSyXxiA at mail dot gmail dot com> <CAOGi=dNHHvNriOMWmj2K3Ym7n6G83mGOyUzMtNY91nFr8=7G9w at mail dot gmail dot com> <CAOGi=dOJX3saKoa5YiDdveOqAb_=Sev4cBKyh7_gkXBU8_4=+g at mail dot gmail dot com> <CAMe9rOpEhNffr5iZUZLFp4QyBAE-Xrxna8-BQFv=tZXEXdSLSg at mail dot gmail dot com> <CAOGi=dNk7H2+aWh=+3_qwVH9LvWN-eNKcLciW=0J7x1dVL9v+g at mail dot gmail dot com> <CAOGi=dMsSdQi8SuXi2pzCbMm6bCrwJru0rAjtg=cn24CLgOgRg at mail dot gmail dot com>
On Wed, Jun 25, 2014 at 7:45 AM, Ling Ma <ling.ma.program@gmail.com> wrote:
> By modifying test suite, we re-test 403.gcc in two parts: one is below
> 256bytes,
> the other is over 256bytes, The results as gzipped attachment shows
> (compared with pending sse2 memcpy):
> 1. when copy size is below 256 bytes, avx memcpy get almost the same
> performance because its instructions also use 16bytes registers.
>
> 2. when copy size is over 256bytes avx memcpy improve performance from
> 4.9% to 33% because its instructions use 32bytes registers.
>
> So avx memcpy avoid regression for small size and improve performance
> for big size.
>
> Thanks
> Ling
>
I'd like to get it in. Any more feedbacks?
Thanks.
--
H.J.