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Re: [PATCH] powerpc: Optimized strncat for POWER8
- From: "Tulio Magno Quites Machado Filho" <tuliom at linux dot vnet dot ibm dot com>
- To: Rajalakshmi Srinivasaraghavan <raji at linux dot vnet dot ibm dot com>, libc-alpha at sourceware dot org
- Cc:
- Date: Wed, 12 Apr 2017 14:29:05 -0300
- Subject: Re: [PATCH] powerpc: Optimized strncat for POWER8
- Authentication-results: sourceware.org; auth=none
- References: <1491811164-7320-1-git-send-email-raji@linux.vnet.ibm.com>
Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com> writes:
> With new optimized strnlen for POWER8 [1], this patch adds
> strncat for power8 to make use of optimized strlen and strnlen.
> This is faster than POWER7 current implementation for larger strings.
>
> Tested on powerpc64 and powerpc64le.
>
> [1] https://sourceware.org/ml/libc-alpha/2017-03/msg00491.html
>
> --
> 2017-04-10 Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
>
> * sysdeps/powerpc/powerpc64/multiarch/Makefile (sysdep_routines): Add
> strncat-power8.
> * sysdeps/powerpc/powerpc64/multiarch/strncat.c (strncat): Add
> __strncat_power8 to ifunc list.
> * sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c
> (strncat): Add __strncat_power8 to list of strncat functions.
> * sysdeps/powerpc/powerpc64/multiarch/strncat-power8.c: New file.
> diff --git a/sysdeps/powerpc/powerpc64/multiarch/Makefile b/sysdeps/powerpc/powerpc64/multiarch/Makefile
> index 38233a7..0eb3d07 100644
> --- a/sysdeps/powerpc/powerpc64/multiarch/Makefile
> +++ b/sysdeps/powerpc/powerpc64/multiarch/Makefile
> @@ -15,7 +15,8 @@ sysdep_routines += memcpy-power7 memcpy-a2 memcpy-power6 memcpy-cell \
> strchrnul-power8 strchrnul-power7 strchrnul-ppc64 \
> strcpy-power8 strcpy-power7 strcpy-ppc64 stpcpy-power8 \
> stpcpy-power7 stpcpy-ppc64 \
> - strrchr-power7 strrchr-ppc64 strncat-power7 strncat-ppc64 \
> + strrchr-power7 strrchr-ppc64 \
> + strncat-power8 strncat-power7 strncat-ppc64 \
I wonder if these C optimizations should be forced to build using -mcpu and
-mtune. At least for those processors supported by the minimum required GCC
version.
Anyway, it shouldn't affect your patch as -mcpu=power8 isn't available on
GCC 4.7
LGTM.
--
Tulio Magno