Re: [PATCH] raise tsc clocksource rating

Jeremy Fitzhardinge
2007-10-29T23:33:48Z

Ingo Molnar wrote:
> i dont remember us having discussed this before, ever. If there's any
> "fight" about monotonicity and SMP then it would be a pretty onesided
> affair, with you being beaten up seriously ;-)
>

This is part of Xen's ABI, so it isn't easily changed. You're right
that getting monotonicity is a pretty ugly affair of doing something
like "if (now < previous_return) return ++previous_return;", but its
better than using the tsc.

(Last time around, it was "Xen can't use the tsc because it can't ever
be used as a stable timebase" - though I don't think that was you
specifically.)

J