Re: Why does C3 CPU downgrade in kernel 2.4.20?

From: Jeff Garzik (
Date: Tue Dec 10 2002 - 15:17:58 EST

On Tue, Dec 10, 2002 at 08:39:38PM +0100, Daniel Egger wrote:
> Am Die, 2002-12-10 um 17.51 schrieb Alan Cox:
> > Well if you optimise for ppro it won't actually always work.
> Yeah, I had to learn earlier that it seems to support certain
> kind of cmovs but certainly not all of them and some other
> instructions seem also to be missing.


> > Also thescheduling seems to be best with 486.
> > Remember the C3 is a single issue risc processor.
> Do you have pointers to some optimisation manual or whatever?
> gcc currently defines the c3 as 486+mmx+3dnow however I doubt
> that this model is entirely correct and as such leaves some
> space for improvements.

Definitely. Read my email message that went along with that commit for
more details ;-) (finding it isn't hard, it's probably one of the few
gcc-patches mails I have ever sent)

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

This archive was generated by hypermail 2b29 : Sun Dec 15 2002 - 22:00:18 EST