Subject: Re: [Cbe-oss-dev] [patch 3/3] cell: prevent alignment interrupt on local store

From: Arnd Bergmann <[email-masked]>
Date: Thu, 12 Apr 2007 20:43:38 +0200

On Thursday 12 April 2007, Olaf Hering wrote:
> How much will this impact performance on a 970, 74xx or POWER6 if
> everything gets compiled with '--mcpu=$cell', compared to what is used
> today? One gets at least altivec that way.

Building with -mcpu=cell won't work on 970 or g4, because that enables
a few extra instructions that were not present in the older cpus.

If you know you want to build with altivec (i.e. not run on power4 or
older), then '-m32 -mcpu=7450 -mtune=cell' or '-m64 -mcpu=970 -mtune=cell'
would be a reasonable thing to try.

	Arnd <><