Re: [gentoo-amd64] x86_64 optimization patches for glibc.

[Jeremy Huddleston <eradicator@gentoo.org>]

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Hey,  I just finished reading through this thread.  I'm not as good
keeping up on the lists as I should be.

BUT... This sounds promising.  Unfortunately you send the email just
after I unmasked 2.3.5-r1, so it's not going to get in there, but it
could get into the next release with further testing.  Can you post both
patches to the bug, and I'll try to take care of getting the libm patch
to apply if nobody beats me to it.  Also be sure to report back the bug
number, so folks here can follow it too.

Thanks,
Jeremy

On Sat, 2005-07-23 at 16:48 +0200, Simon Strandman wrote:
> Hi!
> 
> Some binary distros like Mandrake and suse patches their glibcs with 
> x86_64 optimized strings and an x86_64 optimized libm to improve 
> performance.
> 
> I tried extracting those patches from an mandrake SRPM and add them to 
> the glibc 2.3.5 ebuild. The x86_64 optimized strings patch built and 
> worked perfectly and gave a large speedup as you can see below. But I 
> couldn't get glibc to build with the libm patch because of unresolved 
> symbols (and I'm no programmer so I have no idea how to fix that).
> 
> I found a small C program on a suse mailing-list to measure glibc memory 
> copy performance:
> http://lists.suse.com/archive/suse-amd64/2005-Mar/0220.html
> 
> With the glibc 2.3.5 currently in gentoo I get:
> isidor ~ # ./memcpy 2200 1000 1048576
> Memory to memory copy rate = 1291.600098 MBytes / sec. Block size = 1048576.
> 
> But with glibc 2.3.5 + amd64 optimized strings I get:
> isidor ~ # ./memcpy 2200 1000 1048576
> Memory to memory copy rate = 2389.321777 MBytes / sec. Block size = 1048576.
> 
> That's an improvement of over 1000mb/s! Suse 9.3 also gives about 
> 2300mb/s out of the box.
> 
> How about adding these patches to gentoo? Perhaps in glibc 2.3.5-r1 
> before it leaves package.mask? I'll create a bugreport about it if you 
> agree!
> 
> This .tar.bz2 contains the glibc directory from my overlay with the 
> mandrake patches included in files/mdk, but the libm patches are 
> commented out in the ebuild.
> http://snigel.no-ip.com/~nxsty/linux/glibc.tar.bz2
> 
> -- 
> Simon Strandman <simon.strandman@telia.com>


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