Subject: Re: [PATCH] Set cpu explicitly in kernel compiles

From: Kumar Gala <[email-masked]>
Date: Thu, 5 May 2005 09:00:50 -0500

On May 5, 2005, at 7:24 AM, Dan Malek wrote:

>
>
> On May 5, 2005, at 1:22 AM, Paul Mackerras wrote:
>  > If you think we should have -mcpu=xxx on the command line for 4xx,
>  > 44x, 8xx, etc., then that's fine, but that is a separate problem 
> from
>  > what my patch was addressing (one which my patch might make it 
> easier
>  > to fix, though).
>
> I think that is exactly what we want, although I don't know how that is
>  separate from the patch you sent.  My original comment was the patch
>  fixes the problem for only one of the cpu cores, not all of them.  
> Which
>  then led into the subsequent suggestion of making the biarch work
>  like the past compilers, and we must specific the flags for POWER4
>  instead of the other way around.  Without explicit -mcpu flags, the
>  existing compiler behavior is just fine .....  but, I guess I'd be
> standing
>  in the way of progress to want this :-)

I agree with Dan here.  I think we should go ahead and extend the patch 
to set -mcpu and -mtune flags for the list of processors we have in 
"Processor Type".  If I'm building a kernel for e500 or 4xx I might as 
well get a kernel that is tuned a bit more for the subarch.  
Additionally, there should be some expert override ability, so if I 
really want to do -mcpu=7455 -mtune=7455 I can.

- kumar