Re: Intel Makefile Suggestion

Kurt Garloff (K.Garloff@ping.de)
Wed, 30 Dec 1998 10:03:35 +0100

On Tue, Dec 29, 1998 at 02:28:37PM -0600, Shaw Terwilliger wrote:
> It would be convenient for me to put the "-mpentium
> -march=pentium" flags in the 586 config (and likewise for
> 686), but I recognize that older versions of GCC might balk
> at this. That's fine. I would like to suggest that the
> -m486 be taken out of those blocks, though. Is this a bad
> idea?

No, it's a good idea!
It is unclear whether kernels produced with -m486 by the old gcc-2723
are faster on Pentiums and K6s and PentiumIIs than -m386. One of the pgcc
developers (M. Lehmann?) pointed that out some time ago, that the -m486
-malign-functions=2 ... is not very useful.
I'd guess, the K6, e.g., is faster with -m386 than with -m486, but best with
-mpentiumpro if available ... (I did some test with a numerical application
some time ago with egcs-2.91.5x, so it's not entirely guessed, but the
kernel is quite different from my numerical C++ code.)

Regards,

-- 
Kurt Garloff <kurt@garloff.de>                           [Dortmund, FRG]  
Plasma physics, high perf. computing              [Linux-ix86,-axp, DUX]
PGP key on http://www.garloff.de/kurt/        [Linux SCSI driver: DC390]


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