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From: Andrew Pinski <pinskia@gmail.com>
To: Steve Ellcey <sellcey@mips.com>
Cc: "Carlos O'Donell" <carlos@systemhalted.org>,
	"Joseph S. Myers" <joseph@codesourcery.com>,
		"Carlos O'Donell" <carlos@redhat.com>,
	"libc-ports@sourceware.org" <libc-ports@sourceware.org>
Subject: Re: [patch, mips] Improved memset for MIPS
Date: Fri, 13 Dec 2013 00:22:00 -0000	[thread overview]
Message-ID: <CA+=Sn1kuXWKxi7XkEDqexcbMTkaypdqibG5axQC-tH6mdP6WKw@mail.gmail.com> (raw)
In-Reply-To: <1386893669.2764.30.camel@ubuntu-sellcey>

On Thu, Dec 12, 2013 at 4:14 PM, Steve Ellcey <sellcey@mips.com> wrote:
> On Thu, 2013-12-12 at 19:01 -0500, Carlos O'Donell wrote:
>
>> > I noticed this patch causes some performance regressions on Octeon due
>> > to having 128 byte cache lines.
>> > Changing PREFETCH_CHUNK/PREFETCH_FOR_STORE to assume 128 byte cache
>> > line gives us the performance back and improves over the original code
>> > at least 15%.
>> > That is:
>> > #  define PREFETCH_CHUNK 128
>> > #  define PREFETCH_FOR_STORE(chunk, reg) \
>> >     pref PREFETCH_STORE_HINT, (chunk)*128(reg);
>>
>> Submit a patch for that?
>>
>> We have microbenchmarks now, but the next hardest
>> part is going to be archiving data by device so that
>> the community can help track performance and point
>> out regressions like this.
>>
>> Cheers,
>> Carlos.
>
> Unless the change is under some kind of ifdef for Octeon changing this
> will probably slow down other MIPS chips.  Most of them have 32 byte
> cache lines.

I think once ifunc support has been finalized, it would be useful to
build memset optimized for Octeon but until then I think it might be
best to disable the prefetching in the generic mips code.

Thanks,
Andrew Pinski


>
> Steve Ellcey
> sellcey@mips.com
>
>

  reply	other threads:[~2013-12-13  0:22 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-05 17:06 Steve Ellcey 
2013-09-06  0:40 ` Mike Frysinger
2013-09-06 15:42   ` Steve Ellcey
2013-09-06  4:18 ` Carlos O'Donell
2013-09-06 16:03   ` Steve Ellcey
2013-09-06 17:12     ` Carlos O'Donell
2013-09-06 23:33       ` Steve Ellcey
2013-09-07  2:38         ` Carlos O'Donell
2013-09-10 20:31           ` Steve Ellcey
2013-09-10 21:01             ` Carlos O'Donell
2013-09-10 21:14               ` Steve Ellcey
2013-09-10 22:35                 ` Carlos O'Donell
2013-09-10 22:38                   ` Carlos O'Donell
2013-09-07  5:46         ` Andreas Schwab
2013-09-06 14:31 ` Joseph S. Myers
2013-09-06 15:58   ` Steve Ellcey
2013-09-06 16:09     ` Joseph S. Myers
2013-09-06 16:50       ` Steve Ellcey
2013-09-06 16:59         ` Joseph S. Myers
2013-09-06 17:43           ` Steve Ellcey
2013-09-06 18:57             ` Brooks Moses
2013-09-18 17:41           ` Steve Ellcey
2013-09-19 15:25             ` Carlos O'Donell
2013-09-19 17:02               ` Steve Ellcey
2013-09-20 16:43             ` Joseph S. Myers
2013-09-20 17:32               ` Steve Ellcey
2013-12-12 22:19                 ` Andrew Pinski
2013-12-13  0:01                   ` Carlos O'Donell
2013-12-13  0:14                     ` Steve Ellcey
2013-12-13  0:22                       ` Andrew Pinski [this message]
2013-12-13  4:40                       ` Carlos O'Donell
2013-09-06 16:59       ` Steve Ellcey

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