Re: sched_clock() uses are broken

Andi Kleen
2006-05-03T09:16:35Z

On Wednesday 03 May 2006 11:11, Mike Galbraith wrote:
> On Wed, 2006-05-03 at 09:40 +0200, Andi Kleen wrote:
> > On Wednesday 03 May 2006 09:09, Mike Galbraith wrote:
> >
> > > Given that most people are going to end up using the pm_timer anyway, I
> > > don't see the point of even having a sched_clock(). If it's jiffy
> > > resolution, it's useless. If it's wildly inaccurate (as it is in the
> > > SMP case, monotonicity issues aside) it's more than useless.
> >
> > For sched_clock TSC is always used and it's fine - sched_clock
> > doesn't require the guarantees that make TSC often useless otherwise
>
> Regrettable, that's not true.

Hmm, maybe I'm thinking too much x86-64. At least on x86-64 it's true.

I don't see a big reason to not do this on i386 either, except
on systems that truly don't have a TSC (386/486)

Ok i suppose if you don't want cruft you can always go to 64bit @)

-Andi