On Wed, Apr 17, 2013 at 09:52:39PM +0200, Martin Wawro wrote: > Hi Stefan, > > > The host is interesting too if you suspect KVM is involved in the > > performance issue (rather than it being purely an application issue > > inside the guest). For example, pidstat (from the sysstat package) on > > the host can tell you the guest mode CPU utilization percentage. That's > > useful for double-checking that the guest is indeed using up a lot of > > CPU time (the guest data you posted suggests it is). > > I added it to the host logging to have more information next time something > goes haywire. > > > > > What does top or ps say about the 79% userspace CPU utilization? > > Perhaps this is unrelated to KVM and simply a buggy application going > > nuts. > > > > In this case, it was postgres (we have a couple of instances running on the > guest). But it can also be another daemon process that usually behaves very well, > so no real culprit to pinpoint it to. > We have the same setup (including OS versions and binary versions) in other > locations (on "physical machines") running for years without any problems, > so I doubt that this is an application issue. Another hint that it is not an > application issue is the fact, that when we shutdown the processes that generate > the load, the load average goes down for a couple of seconds and then again > rises to sky-high values with another process consuming the load (until nothing > is left running on the machine except for syslogd :-) ). I see. That's a good reason to carefully monitor the host for things that could interfere with guest performance. Stefan -- 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
