From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750760AbVJ1Voz (ORCPT ); Fri, 28 Oct 2005 17:44:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750772AbVJ1Voz (ORCPT ); Fri, 28 Oct 2005 17:44:55 -0400 Received: from e32.co.us.ibm.com ([32.97.110.150]:29068 "EHLO e32.co.us.ibm.com") by vger.kernel.org with ESMTP id S1750760AbVJ1Voz (ORCPT ); Fri, 28 Oct 2005 17:44:55 -0400 Subject: Re: Bug: timer going backward on a dual core From: john stultz To: Claudio Scordino Cc: kernelnewbies@nl.linux.org, linux-kernel@vger.kernel.org In-Reply-To: <200510282339.16196.cloud.of.andor@gmail.com> References: <200510282109.42054.cloud.of.andor@gmail.com> <200510282227.36433.cloud.of.andor@gmail.com> <1130532212.27168.417.camel@cog.beaverton.ibm.com> <200510282339.16196.cloud.of.andor@gmail.com> Content-Type: text/plain Date: Fri, 28 Oct 2005 14:44:48 -0700 Message-Id: <1130535889.27168.423.camel@cog.beaverton.ibm.com> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2005-10-28 at 23:39 +0200, Claudio Scordino wrote: > On Friday 28 October 2005 22:43, john stultz wrote: > > On Fri, 2005-10-28 at 22:27 +0200, Claudio Scordino wrote: > > > > > We have a dual-core AMD64 with the new kernel 2.6.14 and the > > > > > timer goes backward... > > > > > > > > > > > > > > > CONFIGURATION: > > > > > > > > > > Kernel: 2.6.14 > > > > > Distribution: Gentoo Linux 2005.0 > > > > > Processor: Athlon 64 x2 4200+ (dual core) > > > > > Motherboard: Abit KN8 > > > > > Memory: 1GB PC3200 > > > > > > > > > > > > > > > PROBLEM: > > > > > > > > > > gettimeofday goes backward and returns values that are not monotonic, > > > > > giving values that are smaller than values returned before. > > > > > > > > > > The system has been tested with timer as PIT, PIT/TSC and PM and the > > > > > problem occurs with all the configurations. > > > > > > > > > > Here is the config file that we used for the PM configuration. > > > > > > > > > > Any suggestion ? > > > > > > > > Booting w/ idle=poll tends to work around this issue. You might check > > > > with your motherboard vendor for an updated BIOS that supports HPET or > > > > the ACPI PM timer. > > > > > > We already updated the BIOS with the latest version. > > > > > > Also the booting command idle=poll doesn't work. > > > > Hmm. Not sure then. Is this a new regression on the same hardware? > > Yes, we tried with idle=poll and the problem occurred again. Sorry for the confusion, I meant if the problem is new to 2.6.14, or if it also happened with 2.6.13? > > Would you mind filing a bug (http://bugzilla.kernel.org )on this and > > attaching your config and dmesg there? > > Sure. Please assign it to me or add me to the cc list. thanks -john