From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933006AbXJPKj1 (ORCPT ); Tue, 16 Oct 2007 06:39:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758319AbXJPKjT (ORCPT ); Tue, 16 Oct 2007 06:39:19 -0400 Received: from E23SMTP04.au.ibm.com ([202.81.18.173]:39320 "EHLO e23smtp04.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757795AbXJPKjS (ORCPT ); Tue, 16 Oct 2007 06:39:18 -0400 Message-ID: <471494A1.8030504@linux.vnet.ibm.com> Date: Tue, 16 Oct 2007 16:08:25 +0530 From: Balbir Singh Reply-To: balbir@linux.vnet.ibm.com Organization: IBM User-Agent: Thunderbird 1.5.0.13 (X11/20070824) MIME-Version: 1.0 To: Frans Pop CC: Christian Borntraeger , Chuck Ebbert , Greg KH , stable@kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar Subject: Re: [stable] 2.6.23 regression: top displaying 9999% CPU usage References: <200710122231.50739.elendil@planet.nl> <200710161029.27132.borntraeger@de.ibm.com> <471484B3.9010903@linux.vnet.ibm.com> <200710161211.40285.elendil@planet.nl> In-Reply-To: <200710161211.40285.elendil@planet.nl> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Frans Pop wrote: > On Tuesday 16 October 2007, Balbir Singh wrote: >> I am trying to think out loud as to what the root cause of the problem >> might be. In one of the discussion threads, I saw utime going backwards, >> which seemed very odd, I suspect that those are rounding errors. > > I only remembered stime going backwards, but looking back at the mails > you are right, there has been one case of utime going backwards too. > stime going backwards happens _much_ more frequently. > >> I have tried and not had any success reproducing the problem, could you >> please help me with some pointers/steps to reproduce the problem? > > I can reproduce the problem reliably for two KDE programs I have running > permanently on my system: kontact and amarok. Both of these wake up > regularly and use some (not very much) processor capacity before going to > sleep again. Any process that has that that characteristic should do. > > /me thinks a bit and tries something > > lol - I have just managed to reproduce this with 'top' itself :-P > Thanks, I know why I am not seeing the problem. My box has CONFIG_VIRT_CPU_ACCOUNTING set. I'll find another box and try. -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL