On Tue, Jan 29, 2002 at 02:14:32PM -0500, Mark Hahn wrote:
> > - what stop us from using -mregparm=3 gcc switch ?
>
> I dimly recall that it can generage bad code, perhaps only
> on old compilers.
Bad code, hmm ... slow code or wrong code ?
IIRC gcc 2.95.3 declared as minimal requirement for kernel compilation,
so may be it's not an issue anymore ?
>
> > - same with -Os -malign-loops=1 -malign-jumps=1 ?
>
> 2 is probably always the lowest you should go, and indeed,
> I think that's all the compiler permits.
>
gcc (at least 2.95.2) permits 1, but i didn't check generated code.
> > - any tool to measure perfomance gain/penalty of above ?
>
> lmbench. it has to be a microbenchmark to measure this sort of thing,
> though a sanity check (kernel compile) would also be useful.
Thanks, i'll test these issues this weekend.
Best regards.
-- Andrey Panin | Embedded systems software engineer pazke@orbita1.ru | PGP key: wwwkeys.eu.pgp.net
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