Re: smp guest questions

[Avi Kivity <avi@redhat.com>]

On 06/17/2009 11:38 AM, Michael Tokarev wrote:
> After seeing words from Avi about that smp guests
> are ok now, I descided to try.  And immediately
> got a few questions.
>
> Running on a Phenom 9750 machine (PhenomI), AMD780G
> chipset.  Host is 2.6.29 x86-64, qemu-kvm 0.10.5,
> guests are linux with kvm paravirt bits enabled, also
> dynticks (on both host and guest).
>
>
> When booting a 2-CPU guest, I see in dmesg:
>
> PM-Timer running at invalid rate: 200% of normal - aborting.
>
> and indeed, in available_clocksource there's no pmtimer.
> Should I be concerned?  It does not look healthy.
>

It's a bug, please post guest details (kernel version, bitness).

Copying Marcelo.

>
> Some time later, I see stuff like:
>
> hrtimer: interrupt too slow, forcing clock min delta to 47210997 ns
>
> Which reminds me issues I had with broken hpet (time goes
> back-n-forth with similar messages shown in dmesg, but
> about hpet not hrtimer).  Also does not look healthy.
>
>
> I haven't seen either of the two messages above on any of
> single-processor guests so far, at least with recent kernels
> and kvm userspace, only on smp (2 cpu for now).

Please also post host /proc/cpuifo.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.