[PATCH] Set cpu explicitly in kernel compiles

Kumar Gala kumar.gala at freescale.com
Wed May 4 23:45:51 EST 2005

On May 4, 2005, at 2:05 AM, Paul Mackerras wrote:

> What do people think of this patch?  The motivation for it is that a
>  biarch gcc-4.0 will by default tune for POWER4, even for a 32-bit
>  compile, meaning that we end up with a lot of nops we don't need.
>  This also takes out -mstring.
> With this, the text size reduces by about 120k for my normal config
>  when compiling with a biarch gcc-4.0.  The text size also reduces
>  slightly when compiling with the Debian gcc-3.3.5 (32-bit only, not
>  biarch).

What is attributed to this large of a text size change.  I've always 
assumed the -mcpu and -mtune options really only effected code 
scheduling.  This seems really odd since there arent really that many 
different instructions between the various PPC variants.

- kumar

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