Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751510Ab3HTPPT (ORCPT ); Tue, 20 Aug 2013 11:15:19 -0400 Received: from mail-we0-f174.google.com ([74.125.82.174]:42596 "EHLO mail-we0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751381Ab3HTPPP (ORCPT ); Tue, 20 Aug 2013 11:15:15 -0400 Date: Tue, 20 Aug 2013 17:15:11 +0200 From: Frederic Weisbecker To: Sergey Senozhatsky , Stanislaw Gruszka Cc: Ingo Molnar , Peter Zijlstra , "Paul E. McKenney" , Borislav Petkov , linux-kernel@vger.kernel.org Subject: Re: [sched next] overflowed cpu time for kernel threads in /proc/PID/stat Message-ID: <20130820151509.GA17441@somewhere> References: <20130820111426.GA27828@swordfish.datadirectnet.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130820111426.GA27828@swordfish.datadirectnet.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: 2306 Lines: 45 On Tue, Aug 20, 2013 at 02:14:26PM +0300, Sergey Senozhatsky wrote: > Hello, > 3.11.0-rc6-next-20130820 > > at some point an overflowed cpu time is reported in /proc/PID/stat > > cat /proc/10/stat > 10 (rcu_preempt) S 2 0 0 0 -1 2129984 0 0 0 0 0 406 0 0 20 0 1 0 10 0 0 18446744073709551615 0 0 0 0 0 0 0 2147483647 0 18446744073709551615 0 0 17 0 0 0 0 0 0 0 0 0 0 0 0 0 0 > cat /proc/10/stat > 10 (rcu_preempt) S 2 0 0 0 -1 2129984 0 0 0 0 0 406 0 0 20 0 1 0 10 0 0 18446744073709551615 0 0 0 0 0 0 0 2147483647 0 18446744073709551615 0 0 17 0 0 0 0 0 0 0 0 0 0 0 0 0 0 > cat /proc/10/stat > 10 (rcu_preempt) S 2 0 0 0 -1 2129984 0 0 0 0 0 407 0 0 20 0 1 0 10 0 0 18446744073709551615 0 0 0 0 0 0 0 2147483647 0 18446744073709551615 0 0 17 0 0 0 0 0 0 0 0 0 0 0 0 0 0 > cat /proc/10/stat > 10 (rcu_preempt) S 2 0 0 0 -1 2129984 0 0 0 0 0 407 0 0 20 0 1 0 10 0 0 18446744073709551615 0 0 0 0 0 0 0 2147483647 0 18446744073709551615 0 0 17 0 0 0 0 0 0 0 0 0 0 0 0 0 0 > cat /proc/10/stat > 10 (rcu_preempt) S 2 0 0 0 -1 2129984 0 0 0 0 1844674407370 477 0 0 20 0 1 0 10 0 0 18446744073709551615 0 0 0 0 0 0 0 2147483647 0 18446744073709551615 0 0 17 0 0 0 0 0 0 0 0 0 0 0 0 0 0 > ^^^^^^^^^ > cat /proc/10/stat > 10 (rcu_preempt) S 2 0 0 0 -1 2129984 0 0 0 0 1844674407370 597 0 0 20 0 1 0 10 0 0 18446744073709551615 0 0 0 0 0 0 0 2147483647 0 18446744073709551615 0 0 17 0 0 0 0 0 0 0 0 0 0 0 0 0 0 > > (seems there are several more -1UL in output) > > > oddly enough, I see this happening only for RCU > > ps aux | grep rcu > root 8 0.0 0.0 0 0 ? S 12:42 0:00 [rcuc/0] > root 9 0.0 0.0 0 0 ? S 12:42 0:00 [rcub/0] > root 10 62422329 0.0 0 0 ? R 12:42 21114581:37 [rcu_preempt] > root 11 0.1 0.0 0 0 ? S 12:42 0:02 [rcuop/0] > root 12 62422329 0.0 0 0 ? S 12:42 21114581:35 [rcuop/1] > > -ss Hello, Please upload your config. I'm adding Stanislaw in Cc in case it relates to cputime scaling. -- 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/