From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [Bug #12465] KVM guests stalling on 2.6.28 (bisected) Date: Wed, 21 Jan 2009 16:59:20 +0200 Message-ID: <49773848.4080409@redhat.com> References: <1232410363.4768.21.camel@kulgan.wumi.org.au> <20090120113546.GA26571@elte.hu> <1232455343.4895.4.camel@kulgan.wumi.org.au> <20090120125652.GA1457@elte.hu> <20090120130714.GA11048@elte.hu> <49760E2D.2060109@redhat.com> <1232547932.4895.119.camel@kulgan.wumi.org.au> <49773275.3020203@redhat.com> <1232549502.4895.124.camel@kulgan.wumi.org.au> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1232549502.4895.124.camel-9TBizaOOD0ujuAshGpSIhRCuuivNXqWP@public.gmane.org> Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Kevin Shanahan Cc: Steven Rostedt , Ingo Molnar , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Mike Galbraith , Peter Zijlstra , =?ISO-8859-1?Q?Fr=E9d=E9ric_Weisbecker?= , bugme-daemon-590EEB7GvNiWaY/ihj7yzEB+6BGkLq7r@public.gmane.org Kevin Shanahan wrote: >>> --- 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. > You're right, wasn't thinking properly. This is a tough one. I'll see if I can think of something. Ingo, any ideas? -- error compiling committee.c: too many arguments to function