[PATCH] Set cpu explicitly in kernel compiles

Olaf Hering olh at suse.de
Mon Jul 4 03:29:55 EST 2005

 On Wed, May 04, Paul Mackeras 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).
> If there are no objections I'll send this to Andrew and Linus.

What will be done about this patch? -mcpu=750 reduces .text by 70k.

   text    data     bss     dec     hex filename
3397801  579544  519704 4497049  449e99 ../O-ppc-cpu601/vmlinux
3397502  579544  519704 4496750  449d6e ../O-ppc-cpu604/vmlinux
3397953  579544  519704 4497201  449f31 ../O-ppc-cpu750/vmlinux
3469857  579544  519704 4569105  45b811 ../O-ppc-default/vmlinux

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