Re: [Bug #12465] KVM guests stalling on 2.6.28 (bisected)

[Kevin Shanahan]

On Wed, 2009-01-21 at 16:34 +0200, Avi Kivity wrote:
> Kevin Shanahan wrote:
> > On Tue, 2009-01-20 at 19:47 +0200, Avi Kivity wrote:
> >> Kevin, can you retest with kvm at realtime priority?
...

> > --- hermes-old.wumi.org.au ping statistics ---
> > 900 packets transmitted, 900 received, 0% packet loss, time 899326ms
> > rtt min/avg/max/mdev = 0.093/0.157/3.611/0.117 ms
> >
> > So, a _huge_ difference. But what does it mean?
> 
> It means, a scheduling problem.  Can you run the latency tracer (which 
> only works with realtime priority), so we can tell if it is (a) kvm 
> failing to wake up the vcpu properly or (b) the scheduler delaying the 
> vcpu from running.

Sorry, but are you sure that's going to be useful?

If it only works on realtime threads and I'm not seeing the problem when
running kvm with realtime priority, is this going to tell you what you
want to know?

Not trying to be difficult, but that just didn't make sense to me.

Regards,
Kevin.


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/