Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753011Ab2EKHP2 (ORCPT ); Fri, 11 May 2012 03:15:28 -0400 Received: from e23smtp03.au.ibm.com ([202.81.31.145]:49457 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751710Ab2EKHP0 (ORCPT ); Fri, 11 May 2012 03:15:26 -0400 From: Nikunj A Dadhania To: Avi Kivity , Ingo Molnar , Peter Zijlstra Cc: Andrea Arcangeli , KVM , LKML Subject: Re: KVM: Softlockups in guests while running kernbench In-Reply-To: <87ipg4drgd.fsf@abhimanyu.in.ibm.com> References: <87wr4kjvtk.fsf@abhimanyu.in.ibm.com> <4FAB88B8.5060203@redhat.com> <87pqace4an.fsf@abhimanyu.in.ibm.com> <87ipg4drgd.fsf@abhimanyu.in.ibm.com> User-Agent: Notmuch/0.10.2+70~gf0e0053 (http://notmuchmail.org) Emacs/24.0.95.1 (x86_64-unknown-linux-gnu) Date: Fri, 11 May 2012 12:08:01 +0530 Message-ID: <87obpvw7cm.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain x-cbid: 12051020-6102-0000-0000-00000174DF61 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2157 Lines: 39 On Thu, 10 May 2012 20:16:26 +0530, Nikunj A Dadhania wrote: > On Thu, 10 May 2012 15:39:04 +0530, Nikunj A Dadhania wrote: > > I had a discussion with Avi on IRC, he suggested running a trace on the > host for the sched: tracepoints > > So when I see the console of the guest, i can see the soft-lockup > messages. When I start tracing, soft-lockups disappear. > > Kernbench is started from the host; ps output: > 13359 pts/1 S+ 0:00 perf stat -a -- ssh root@192.168.123.11 cd /root/linux-src; kernbench -f -M -H -o 16 > /root/kbench.log > 13362 pts/1 S+ 0:00 ssh root@192.168.123.11 cd /root/linux-src; kernbench -f -M -H -o 16 > /root/kbench.log > 13373 pts/1 S+ 0:00 perf stat -a -- ssh root@192.168.123.12 cd /root/linux-src; kernbench -f -M -H -o 16 > /root/kbench.log > 13376 pts/1 S+ 0:00 ssh root@192.168.123.12 cd /root/linux-src; kernbench -f -M -H -o 16 > /root/kbench.log > 13387 pts/1 S+ 0:00 perf stat -a -- ssh root@192.168.123.13 cd /root/linux-src; kernbench -f -M -H -o 16 > /root/kbench.log > 13390 pts/1 S+ 0:00 ssh root@192.168.123.13 cd /root/linux-src; kernbench -f -M -H -o 16 > /root/kbench.log > 13401 pts/1 S+ 0:00 perf stat -a -- ssh root@192.168.123.14 cd /root/linux-src; kernbench -f -M -H -o 16 > /root/kbench.log > 13402 pts/1 S+ 0:00 ssh root@192.168.123.14 cd /root/linux-src; kernbench -f -M -H -o 16 > /root/kbench.log > > I have tried following commands trace-cmd: > 1) trace-cmd record -e kvm -e sched -b 100000 -p 13362 > 2) trace-cmd record -e sched -b 100000 -p 13362 > 3) trace-cmd record -e kvm -b 100000 -p 13362 > > I have tried trace-cmd on qemu pid as well, I see similar behaviour in > that case. > > Peterz/Ingo, Any clue on debugging this would help. > With CONFIG_DEBUG_SPINLOCK=y in guest config, I stop seeing the soft-lockup Nikunj -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/