Re: BogoMIPS

Harald Koenig (koenig@tat.physik.uni-tuebingen.de)
Tue, 6 Oct 1998 19:34:07 +0200


On Oct 06, Pavel Machek wrote:

> Hi!
>
> > > > 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.
> >
> > I presume this is a joke.
>
> Sorry, it is not. Someone shown timings of empty loop at they were
> dependend on placement of code in page. (It gives plenty of sense if
> code happens to cross page boundary.)

correct. at least my Intel PODP83 shows this weird behaviour when the loop
is just before a page boundary and IIRC there have been some reports of
other CPUs showing similar effects. my old data should be available on dejanews...

Harald

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