Am 19.09.2010 02:15, Zachary Amsden wrote: > For CPUs with unstable TSC, we null time offset between not just VCPU > switches, but all preemptions of the kvm thread. This makes a bug much > more likely where the kvmclock values are updated before a successful > exit from virt, causing an underflow. > > The null offsetting was added at : bf0fb4a42ba7eb362f4013bd2e93209666793e66 > The underflow happens with this additional patch : > cf839f5da2b0779b9ec8b990f851fb4e7d681da0 > > There is a secondary bug, which is that TSC fails to advance with real > time on unstable TSC, but the fix is much more involved (it requires the > TSC catchup code). > > For now, this patch is sufficient to get things working again for me. ...but not for me. I still face stuck (or infinitely slow) guests that want to use kvmclock once tsc_unstable gets set. Or is this patch addressing a different issue? Jan
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