Re: [PATCH] raise tsc clocksource rating

Ingo Molnar
2007-10-29T22:55:58Z

* Jeremy Fitzhardinge <jeremy@goop.org> wrote:

> > if it's inaccurate why are you exposing it to the guest then? Native
> > only uses the TSC if it's safe and accurate to do so.
>
> It is used as part of the Xen clocksource as a short term
> extrapolator, with correction parameters supplied by the hypervisor.
> It should never be used directly.

that's totally broken then. You cannot create an SMP-safe monotonic
clocksource via interpolation - native does not do it either. Good thing
this problem got exposed, it needs to be fixed.

Ingo