Re: performance in sysdeps/powerpc/memset.S

[Olaf Hering <olh at suse dot de>]

On Thu, Jul 12, Geoff Keating wrote:

> > Date: Thu, 12 Jul 2001 14:33:37 +0200
> > From: Olaf Hering <olh@suse.de>
> 
> > there are some problems with current sysdeps/powerpc/memset.S.
> > It prevents booting a POWER3 machine, and it also slows down memset(). 
> 
> Can you analyze the booting problem further?  I suspect the difficulty
> is due to the use of the dcbz instruction.  Perhaps rewriting the
> routine to not use this instruction would help.

Its that dcbz instruction, some IBM guys working on it. But since a rm
is faster than a vi (or emacs:) it should be a real rewrite to gain
speed :)

> When I originally wrote this routine it provided about a 50% speedup
> on my 601.  It's possible there are changes that would make it
> go faster on newer machines and keep its speed on older ones.

I will try the test on a 601 soon.




Gruss Olaf

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