Re: kvm linux guest hanging for minutes at a time

Avi Kivity
2011-08-09T09:16:10Z

On 08/07/2011 05:06 PM, Thomas Fjellstrom wrote:
> Occasionally when there's heavy cpu and/or io load, a kvm guest will lock up
> for minutes at a time, last occurrence was for about 12 minutes or so, and the
> guest itself reported:
>
> [1992982.639514] Clocksource tsc unstable (delta = -747307707123 ns)
>
> in dmesg after it came back. The only other hint as to what is going on is
> that the irq count for "local timer requests", virtio-input and virtio-
> requests spikes rather high. Also one of the cpu cores on the host was pegged
> the entire time.
>
> The last thing to cause a hang was an "aptitude upgrade" in the guest, which
> was a bit behind, so it had to update over 300 packages.
>
> The host is running 2.6.38-1-amd64 (2.6.38+32) from debian, qemu-kvm 0.14.0,
> and the guest was running 2.6.38-2-amd64 (not sure on the + number).
>
> Is this a known problem, thats hopefully fixed in newer kernels and qemu/kvm
> packages?
>

Your guest isn't using kvmclock for some reason. Is it compiled in the
guest kernel? What are the contents of
/sys/devices/system/clocksource/clocksource0/available_clocksource and
/sys/devices/system/clocksource/clocksource0/current_clocksource (in the
guest filesystem)?

--
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