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Subject: Re: AltiVec in the kernel
From: Daniel Ostrow <dostrow@gentoo.org>
To: "Brian D. Carlstrom" <bdc@carlstrom.com>
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Date: Thu, 20 Jul 2006 15:39:47 -0700
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Cc: Olof Johansson <olof@lixom.net>,
	'linuxppc-dev list' <linuxppc-dev@ozlabs.org>,
	'Paul Mackerras' <paulus@samba.org>
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On Thu, 2006-07-20 at 14:56 -0700, Brian D. Carlstrom wrote:
> At Thu, 20 Jul 2006 14:05:23 -0500, Olof Johansson wrote:
> > On Thu, Jul 20, 2006 at 11:47:04AM -0700, Brian D. Carlstrom wrote:
> > > A quick grep memcpy in the recent glibc sources on my linux/ppc box
> > > seems to show no where near that level of optimization, but I admit
> > > that I could have missed something.
> > 
> > http://penguinppc.org/dev/glibc/glibc-powerpc-cpu-addon.html
> 
> Very interesting. According to that page, the memcpy optimizations seem
> to be using 64-bit operations and that 128-bit AltiVec operations are
> still being solicited. 
> 
> I was encouraged to see the following: 
> 
>     If you need to build generic distributions (supporting several
>     <cpu_types>) you can leverage the dl_procinfo support built into
>     glibc. This mechanism allows for multiple versions of the core
>     libraries (libc, libm, librt, libpthread, libpthread_db) to be
>     stored in hardware/platform specific subdirectories under /lib[64].
> 
> However, I'm guessing this addon is not something found in common
> distributions for PowerPC like Debian, Fedora, Gentoo, Ubuntu, ...

It has been part of Gentoo's glibc since 2.4 came out.

--Dan