Messages in this thread | | | Date | Wed, 30 Jan 2002 11:00:25 +0300 | From | Andrey Panin <> | Subject | Re: [ACPI] ACPI mentioned on lwn.net/kernel |
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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[unhandled content-type:application/pgp-signature] | |