Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751982Ab3EHVQu (ORCPT ); Wed, 8 May 2013 17:16:50 -0400 Received: from e36.co.us.ibm.com ([32.97.110.154]:39917 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750774Ab3EHVQt (ORCPT ); Wed, 8 May 2013 17:16:49 -0400 Date: Wed, 8 May 2013 14:16:35 -0700 From: "Paul E. McKenney" To: Dave Jones , Linux Kernel Subject: Re: rcu_preempt running flat out on idle desktop. Message-ID: <20130508211634.GP3648@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20130508203042.GA18895@redhat.com> <20130508205258.GN3648@linux.vnet.ibm.com> <20130508205633.GB18895@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130508205633.GB18895@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13050821-7606-0000-0000-00000B343FC7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1748 Lines: 37 On Wed, May 08, 2013 at 04:56:33PM -0400, Dave Jones wrote: > On Wed, May 08, 2013 at 01:52:58PM -0700, Paul E. McKenney wrote: > > On Wed, May 08, 2013 at 04:30:42PM -0400, Dave Jones wrote: > > > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > > > 10 root 20 0 0 0 0 S 200.0 0.0 185301:36 rcu_preempt > > > 553 root 20 0 268m 76m 6764 S 200.0 2.6 144579:53 Xorg > > > 1199 root 20 0 0 0 0 S 200.0 0.0 306:17.85 kworker/1:0 > > > 501 root 20 0 0 0 0 S 200.0 0.0 4471:03 kworker/0:2 > > > 12 root 20 0 0 0 0 S 200.0 0.0 67277:16 rcuop/1 > > > 1237 davej 20 0 535m 15m 8484 S 200.0 0.5 3645:16 Terminal > > > 859 davej 20 0 117m 3036 1336 S 200.0 0.1 1986:55 htop > > > > > > There are a lot of processes allegedly using "200%" of CPU time, a handful > > > in the "196%" range, and then a bunch at 0. > > > > Yow!!! 185301 minutes is 128 days, which is a truly impressive amount of > > CPU time to accumulate in a few short hours. > > perf top doesn't show anything out of the ordinary. Just as an idle desktop > should behave, it's spending a bunch of time in delay_tsc. > > > This is 3.9, or Linus's current tree? I am guessing the latter, but > > figured I should ask. > > Yeah, the latter. (v3.9-11572-g5af43c2) Do you have CONFIG_NO_HZ_FULL=y? We just might have a bug in tickless CPU-time accounting... Thanx, Paul -- 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/