[PATCH] x86_64: memcpy/memmove family optimized with AVX512

[Carlos O'Donell]

On 01/12/2016 09:13 AM, Andrew Senkevich wrote:
> Hi,
> 
> here is AVX512 implementations of memcpy, mempcpy, memmove,
> memcpy_chk, mempcpy_chk, memmove_chk.
> It shows average improvement more than 30% over AVX versions on KNL
> hardware, performance results attached.
> Ok for trunk?
> 
> 2016-01-12  Andrew Senkevich  <andrew.senkevich@intel.com>
> 
>         * sysdeps/x86_64/multiarch/Makefile: Added new files.
>         * sysdeps/x86_64/multiarch/ifunc-impl-list.c: Added new tests.
>         * sysdeps/x86_64/multiarch/memcpy-avx512-no-vzeroupper.S: New file.
>         * sysdeps/x86_64/multiarch/mempcpy-avx512-no-vzeroupper.S: Likewise.
>         * sysdeps/x86_64/multiarch/memmove-avx512-no-vzeroupper.S: Likewise.
>         * sysdeps/x86_64/multiarch/memcpy.S: Added new IFUNC branch.
>         * sysdeps/x86_64/multiarch/memcpy_chk.S: Likewise.
>         * sysdeps/x86_64/multiarch/memmove.c: Likewise.
>         * sysdeps/x86_64/multiarch/memmove_chk.c: Likewise.
>         * sysdeps/x86_64/multiarch/mempcpy.S: Likewise.
>         * sysdeps/x86_64/multiarch/mempcpy_chk.S: Likewise.

Looks good to me.

Thanks for the results. Yes, it looks like consistently ~30% over AVX.
My only thoughts are: How does this scale as you add more threads to
the process that try to use those functional units? Have you done any
scalability testing on these implementations?

Cheers,
Carlos.