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Re: [PATCH] Don't use SSE4_2 instructions on Intel Silvermont Micro Architecture.
- From: "Carlos O'Donell" <carlos at redhat dot com>
- To: OndÅej BÃlka <neleai at seznam dot cz>
- Cc: Andi Kleen <andi at firstfloor dot org>, Dmitrieva Liubov <liubov dot dmitrieva at gmail dot com>, "H.J. Lu" <hjl dot tools at gmail dot com>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Fri, 21 Jun 2013 09:37:31 -0400
- Subject: Re: [PATCH] Don't use SSE4_2 instructions on Intel Silvermont Micro Architecture.
- References: <20130618064910 dot GA19972 at domone dot kolej dot mff dot cuni dot cz> <CAHjhQ90Fc0kdZfQrUwLwpKbz2va4X9rzf1EkGD-s-RH-iF7guQ at mail dot gmail dot com> <CAHjhQ92qfjdKZthqAwxCVuCnLqDr2stdEbQpne5rKhzJPeN_cQ at mail dot gmail dot com> <51C23583 dot 1070307 at redhat dot com> <CAHjhQ93vWnCiVVU9MPoGptjQtn2J2PCDT2B7ZfXiKt+Cv_Rh_w at mail dot gmail dot com> <51C307A5 dot 7030608 at redhat dot com> <20130620151711 dot GA4891 at domone dot kolej dot mff dot cuni dot cz> <51C317AA dot 6080502 at redhat dot com> <20130621012427 dot GA4574 at domone dot kolej dot mff dot cuni dot cz> <51C3A8E4 dot 1060305 at redhat dot com> <20130621132826 dot GA7973 at domone dot kolej dot mff dot cuni dot cz>
Ondrej,
> Here,
> http://sourceware.org/bugzilla/show_bug.cgi?id=15424
> I am not sure which original mistake was but there was problem that gcc
> optimized call away.
That's great, we found the problem, filed an issue and it's fixed.
The framework is in its infancy, and we need the help of experienced
people, including you, if we're going to have a chance at making the
contributed code better.
Are you suggesting we could we have done something better?
Do you have any recommendations?
>> In my LFCS2013 talk I came out and directly asked for people
>> with performance measurement experience to help glibc.
>>
> Could you also invite them to say their opinion?
Certainly.
>> Surely the implementation can't offend you so much that you
>> aren't willing to help us make it better? :-)
>>
> A question is if I staring from scratch would be faster than writing
> patch, waiting few weeks for review and meanwhile I need to rewrite
> patch because half internals changed and more bugs were introduced.
Write *new* tests from scratch, contribute them, and then we'll
phase out the old tests as we have new tests that cover the old
test behaviours?
We can and should have multiple tests.
Cheers,
Carlos.