On Tue, May 14, 2013 at 12:05:13PM +0300, Gleb Natapov wrote: > On Thu, May 09, 2013 at 08:21:41PM -0300, Marcelo Tosatti wrote: > > > > kvmclock updates which are isolated to a given vcpu, such as vcpu->cpu > > migration, should not allow system_timestamp from the rest of the vcpus > > to remain static. Otherwise ntp frequency correction applies to one > > vcpu's system_timestamp but not the others. > > > > So in those cases, request a kvmclock update for all vcpus. The worst > > case for a remote vcpu to update its kvmclock is then bounded by maximum > > nohz sleep latency. > > > Does this mean that when one vcpu is migrated all others are kicked out > from a guest mode? Yes, those which are in guest mode. For guests with large number of vcpus this is a problem, but i can't see a simpler method to fix the bug for now. Yes, this aspect must be improved (however, the bug incurs on timers in the guest taking tens of milliseconds with vcpu->pcpu pinning, which can be unacceptable). -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
