Subject: Re: AltiVec in the kernel

From: "Brian D. Carlstrom" <[email-masked]>
Date: Thu, 20 Jul 2006 14:56:33 -0700

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, ...

-bri