On Tue, 2014-07-22 at 17:34 +0100, Peter Zijlstra wrote: > On Tue, Jul 22, 2014 at 05:17:29PM +0100, Pawel Moll wrote: > > With both Ingo and John showing preference towards the clock alignment, > > so that's where I looked this time (I've already done custom perf > > ioctls, posix clocks... don't really know how many different ways I've > > tried). > > So we should probably also talk about which clock to track, MONO has the > advantage of making it far easier to trace clusters but has the > disadvantage of stacked control loops with NTP adjusting MONO and us > adjusting sched_clock.
John suggested (and I fully agree with him) MONO_RAW, as it is not getting NTP-d. > And I would really prefer to pick 1 and not make it configurable. Same here. One thing I keep in mind is the fact that userspace must be able to say whether it can expect the correlation or not. "Not" being either an architecture which sched_clock is not using the generic solution (I'm sure there will be some) or "not" because of the synchronisation failure. My idea so far was a debugfs file saying this (or missing, which is a message on its own). Pawel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
