On Fri, Aug 09, 2013 at 09:14:13PM +0200, Stefan Pietsch wrote: > On 04.08.2013 14:44, Gleb Natapov wrote: > > On Fri, Aug 02, 2013 at 08:24:38AM +0200, Stefan Pietsch wrote: > >> On 31.07.2013 11:20, Gleb Natapov wrote: > >>> On Wed, Jul 31, 2013 at 11:10:01AM +0200, Stefan Pietsch wrote: > >>>> On 30.07.2013 07:31, Gleb Natapov wrote: > >>>> > >>>>> What happen if you run perf on your host (perf record -a)? > >>>>> Do you see same NMI messages? > >>>> > >>>> It seems that "perf record -a" triggers some delayed NMI messages. > >>>> They appear about 20 or 30 minutes after the command. This seems strange. > >>> Definitely strange. KVM guest is not running in parallel, correct? 20, 30 > >>> minutes after perf stopped running or it is running all of the time? > >> > >> No, the KVM guest ist not running in parallel. But I'm not able to > >> clearly reproduce the NMI messages with "perf record". > >> I start "perf record -a" and after some minutes I stop the recording. > >> > >> After that it seems NMI messages appear within a random period of time. > >> So, I cannot tell what triggers the messages. > > When you run KVM with coreduo cpu model it emulates PMU which basically > > make is perf front end. If you can reproduce the messages with perf too > > it probably means that the problem is not in the KVM itself. If you > > disabled NMI watchdog in the guest the messages may go away. > > Can you send your guest's dmesg when you boot it with coreduo mode? > > > The NMI messages appear in the host only. The guest runs as usual. > > I understand that. But enabling guest nmi watchdog is what makes KVM to use perf subsystem and likely causes this host messages. Try do disable nmi watchdog in a guest and see what happens. -- Gleb. -- 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
