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Re: [PATCH 2/2][BZ #16640] Remove strtok assembly implementation.
- From: "Carlos O'Donell" <carlos at redhat dot com>
- To: OndÅej BÃlka <neleai at seznam dot cz>
- Cc: libc-alpha at sourceware dot org
- Date: Thu, 06 Mar 2014 12:51:07 -0500
- Subject: Re: [PATCH 2/2][BZ #16640] Remove strtok assembly implementation.
- Authentication-results: sourceware.org; auth=none
- References: <20140227123238 dot GA26291 at domone dot podge> <20140227124206 dot GA26474 at domone dot podge> <5318A03D dot 3000705 at redhat dot com> <20140306163241 dot GA11843 at domone dot podge>
On 03/06/2014 11:32 AM, OndÅej BÃlka wrote:
> On Thu, Mar 06, 2014 at 11:20:13AM -0500, Carlos O'Donell wrote:
>> On 02/27/2014 07:42 AM, OndÅej BÃlka wrote:
>>> As followup this patch removes strtok assembly implementation as it is
>>> around 2-4 times slower on sse4_2 capable machines which is a majority,
>>> as previous benchtest demonstrated.
>>>
>>> You could try to gain some cycles on older machines by using ifuncs but
>>> is a strtok important enough to complicate matters?
>>>
>>> OK to commit?
>>>
>>> * sysdeps/i386/i686/strtok.S: Remove.
>>> * sysdeps/i386/i686/strtok_r.S: Likewise.
>>> * sysdeps/i386/strtok.S: Likewise.
>>> * sysdeps/i386/strtok_r.S: Likewise.
>>> * sysdeps/x86_64/strtok.S: Likewise.
>>> * sysdeps/x86_64/strtok_r.S: Likewise.
>>
>> Is this still the case with the oldest compiler we support?
>>
> I do not understand what are you reffering to.
If you remove the strtok assembly implemetnation, the build will
fall back on use the C implementation e.g. string/strtok.c.
That C implementation will have been compiled by whichever
compiler you're using for your build. In glibc we support a wide
range of compilers from gcc 4.4 and newer. Do the older compilers,
specifically gcc 4.4, still generate good code for strtok.c which
is faster than strtok.S?
Cheers,
Carlos.