Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752711Ab3FFPnS (ORCPT ); Thu, 6 Jun 2013 11:43:18 -0400 Received: from mail-wg0-f49.google.com ([74.125.82.49]:62583 "EHLO mail-wg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751033Ab3FFPnR (ORCPT ); Thu, 6 Jun 2013 11:43:17 -0400 Date: Thu, 6 Jun 2013 17:43:13 +0200 From: Frederic Weisbecker To: Dave Jones , paulmck@linux.vnet.ibm.com, Linux Kernel , Ingo Molnar Subject: Re: rcu_preempt running flat out on idle desktop. Message-ID: <20130606154311.GA5688@somewhere> References: <20130508203042.GA18895@redhat.com> <20130509211026.GA22723@redhat.com> <20130514012105.GB12749@somewhere> <20130606153136.GA12823@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130606153136.GA12823@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6315 Lines: 76 On Thu, Jun 06, 2013 at 11:31:36AM -0400, Dave Jones wrote: > On Tue, May 14, 2013 at 03:21:07AM +0200, Frederic Weisbecker wrote: > > On Thu, May 09, 2013 at 05:10:26PM -0400, Dave Jones wrote: > > > On Thu, May 09, 2013 at 11:02:08PM +0200, Frederic Weisbecker wrote: > > > > > > > > RCU options for this build are.. > > > > > > > > > I can't reproduce that issue even with the above setting. Could you > > > > please send me your whole config? > > > > > > http://paste.fedoraproject.org/11363/36813375/raw/ > > > > Sorry it took me some time to get that config booting, I ran into > > other unrelated crashes. > > > > So I'm observing the exact opposite than you: the processes appear to > > have no load nor to consume cputime. Even if I use some dumb user loop. > > Top don't even show it. > > > > I'm digging further and will tell you when I get more info. > > So I'm still seeing this on rc4. > > Here's my 'idle' firewall, just routing packets: > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 4405 root 20 0 0 0 0 S 400.0 0.0 52336:27 kworker/2:0 > 20968 davej 20 0 115m 1840 1092 R 400.0 0.1 2297:48 top > 964 named 20 0 383m 32m 2896 S 400.0 1.7 81384:54 named > 10 root 20 0 0 0 0 S 400.0 0.0 195403:05 rcu_preempt > 20830 davej 20 0 125m 2172 1024 S 400.0 0.1 939:36.10 sshd > 11 root 20 0 0 0 0 S 400.0 0.0 42644:33 rcuop/0 > 13 root 20 0 0 0 0 S 400.0 0.0 34729:04 rcuop/2 > 754 lighttpd 20 0 54640 2692 1732 S 400.0 0.1 35286:11 lighttpd > 756 root 20 0 216m 10m 6116 S 400.0 0.5 34143:41 snmpd > 35 root 20 0 0 0 0 S 400.0 0.0 12790:56 ksoftirqd/2 > 19893 root 20 0 0 0 0 S 400.0 0.0 12570:49 kworker/0:1 > 20059 root 20 0 0 0 0 S 400.0 0.0 4666:30 kworker/1:1 > 32 root rt 0 0 0 0 S 400.0 0.0 8780:22 watchdog/2 > 792 root 20 0 92220 2516 632 S 400.0 0.1 7821:28 sendmail > 25 root rt 0 0 0 0 S 400.0 0.0 8780:21 watchdog/0 > 26 root rt 0 0 0 0 S 400.0 0.0 8780:22 watchdog/1 > 38 root rt 0 0 0 0 S 400.0 0.0 8780:22 watchdog/3 > 19167 root 20 0 0 0 0 S 400.0 0.0 7804:04 kworker/3:2 > > > Every process is either 400%, or 0%. > > Here's my desktop box, just writing this email: > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 10 root 20 0 0 0 0 S 200.0 0.0 35134:00 rcu_preempt > 12 root 20 0 0 0 0 S 200.0 0.0 14059:47 rcuop/1 > 12528 root 20 0 0 0 0 S 200.0 0.0 1012:56 kworker/0:1 > 12999 davej 20 0 115m 1700 956 R 200.0 0.1 1:09.10 top > 4799 root 20 0 0 0 0 S 200.0 0.0 3510:40 kworker/1:1 > 1 root 20 0 50760 5092 1648 S 0.0 0.2 3:14.96 systemd > 2 root 20 0 0 0 0 S 0.0 0.0 1:40.55 kthreadd > > Every process 200% or 0%. I see, would you mind testing this branch? git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers/urgent It might help, I specially think about 45eacc692771bd2b1ea3d384e6345cab3da10861 ("vtime: Use consistent clocks among nohz accounting") which fixes an issue with cputime accounting that resulted in similar symptoms. Thanks. -- 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/