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Re: [PATCH] [x86_32] Don't use SSE4_2 instructions on Intel Silvermont Micro Architecture.
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Liubov Dmitrieva <liubov dot dmitrieva at gmail dot com>
- Cc: "Carlos O'Donell" <carlos at redhat dot com>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Mon, 1 Jul 2013 12:31:37 -0700
- Subject: Re: [PATCH] [x86_32] Don't use SSE4_2 instructions on Intel Silvermont Micro Architecture.
- References: <CAHjhQ93YUtMz14Aj7JfhJ7Tq++eC+23cA6yubh1KPRpKTvvkaw at mail dot gmail dot com> <51D0967A dot 7050102 at redhat dot com> <CAHjhQ92mTi8OmY7RBC3=sCaX=-xbgGH82pCBz4fCQkBLJcNqOA at mail dot gmail dot com> <CAMe9rOr8o7OnB0T0tG50J7oXmJJF_XOiUDLK6Gsc1tMu-NOFrQ at mail dot gmail dot com> <CAHjhQ90Hrj78WYJ_sQ2Eu7mzf63Wbnuihcv88KBMdxJo5q1Yxg at mail dot gmail dot com>
On Mon, Jul 1, 2013 at 12:27 PM, Liubov Dmitrieva
<liubov.dmitrieva@gmail.com> wrote:
> It is disabled for both. Where do you see it doesn't?
>
From:
http://sourceware.org/git/?p=glibc.git;a=blob_plain;f=sysdeps/i386/i686/multiarch/strcasecmp.S;hb=HEAD
I see __strcasecmp_sse4_2 is used when SHARED is define.
> --
> Liubov
>
> On Mon, Jul 1, 2013 at 7:12 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Mon, Jul 1, 2013 at 5:46 AM, Liubov Dmitrieva
>> <liubov.dmitrieva@gmail.com> wrote:
>>> It doesn't look very good when I summarized the results because there
>>> are too many small lengths cases in your benchmarks.
>>> And small cases are more inaccurate.
>>> Ssse3 looks asymptotically faster. Actually it would better to use
>>> sse2 unaligned versions for Silvermont but we don't have it in glibc
>>> at the moment.
>>> Bot sse4_2 and ssse3 are not the best for SLM.
>>>
>>
>> Why is SSE4.2 strcasecmp disabled only for libc.a,
>> not libc.so? Libc.so is used by most of applications.
>>
>>
>> --
>> H.J.
--
H.J.