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SubjectRe: BogoMIPS
Hi!

> > > > As a result, 2.0.x just does it as a separate subroutine in
> > > >
> > > > arch/i386/lib/delay.S
> > > >
> > > > and that pretty much forces it to not jitter at all. If you'd send me that
> > > > kind of patch I'd accept it.
> >
> > It jitters on cyrix unless you force alignments too. I've not figured out
> > the logic that can cause this just that it happens.
> >
> > > I think the right thing is to use the TSC if the machine has one
> > > (which can be trusted.) That leaves only older, simple machines to
> > > use timing loops.
> >
> > That needs the time.c patches to 2.1.x otherwise you cant use non intel
> > chips TSC or use the TSC on an APM aware kernel
>
> This works and gets rid of the two jmps that everybody complained
> about.

Are you sure? I saw reports where it depended on place in _page_
(imagine udelay loop at page boundary). So you maybe should .align
PAGE_SIZE.

> - "1:\tdecl %0\n\tjns 1b"
> + "\tpushl %%cs\n"
> + "\tpushl $doit\n"
> + "\tlret\n"
> + ".align 16\n"
> + "doit:\tdecl %%eax\n\tjns doit"
> :/* no outputs */
> :"a" (loops)
> :"ax");

--
I'm really pavel@atrey.karlin.mff.cuni.cz. Pavel
Look at http://atrey.karlin.mff.cuni.cz/~pavel/ ;-).

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