Re: Minimizing the Kernel

[Valdis . Kletnieks]

On Wed, 24 Sep 2003 19:13:28 +0200, Maciej Soltysiak said:
> > Well for starters dont use gcc 3 or above.. code size has increased
> > dramatically with thoose versions. sure they give you more optimization
> Hmm, has anyone tried -Os with gcc3+ ?
> Maybe that'd be good for size optimization?

I've usually been compiling with -Os on gcc3 for a while, works for me.

% size */vmlinux
   text    data     bss     dec     hex filename
3034134  620847  224824 3879805  3b337d linux-2.6.0-test4-mm6/vmlinux
3476451  621246  227512 4325209  41ff59 linux-2.6.0-test5-mm2/vmlinux
3034632  622210  226360 3883202  3b40c2 linux-2.6.0-test5-mm3/vmlinux
3037706  623409  226360 3887475  3b5173 linux-2.6.0-test5-mm4/vmlinux

-mm6, -mm3, and -mm4 were compiled with -Os, -mm2 with -O2.  All with gcc 3.3.1
from RedHat Rawhide.  Given how close -mm6, -mm3, and -mm4 are in size, the 12%
or so size saving is almost certainly the efects of -Os rather than changes in
the size of the code.  I could rebuild any of them to get an exact number, but
it would take a while on this laptop....

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