From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261361AbVFCQOY (ORCPT ); Fri, 3 Jun 2005 12:14:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261375AbVFCQOR (ORCPT ); Fri, 3 Jun 2005 12:14:17 -0400 Received: from e33.co.us.ibm.com ([32.97.110.131]:18641 "EHLO e33.co.us.ibm.com") by vger.kernel.org with ESMTP id S261361AbVFCQNm (ORCPT ); Fri, 3 Jun 2005 12:13:42 -0400 Subject: Re: [PATCH 1/4] new timeofday core subsystem (v. B1) From: john stultz To: Frank Sorenson Cc: Andrew Morton , lkml , Tim Schmielau , George Anzinger , albert@users.sourceforge.net, Ulrich Windl , Christoph Lameter , Dominik Brodowski , David Mosberger , Andi Kleen , paulus@samba.org, schwidefsky@de.ibm.com, keith maanthey , Chris McDermott , Max Asbock , mahuja@us.ibm.com, Nishanth Aravamudan , Darren Hart , "Darrick J. Wong" , Anton Blanchard , donf@us.ibm.com, mpm@selenic.com, benh@kernel.crashing.org In-Reply-To: <42A006E8.9000601@tuxrocks.com> References: <1117667378.6801.80.camel@cog.beaverton.ibm.com> <42A006E8.9000601@tuxrocks.com> Content-Type: text/plain Date: Fri, 03 Jun 2005 09:13:30 -0700 Message-Id: <1117815210.3674.6.camel@leatherman> Mime-Version: 1.0 X-Mailer: Evolution 2.0.4 (2.0.4-4) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2005-06-03 at 01:29 -0600, Frank Sorenson wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > john stultz wrote: > > Andrew, All, > > I'm just re-spinning this to resolve a conflict w/ the CPUFREQ changes > > Linus accepted last night. > > > John, > > I have found an issue with these TOD subsystem patches, and I > think it's only an issue on systems that use CPUFREQ. Whenever > the frequency changes, at least some portions of the kernel > get confused about their notion of time. Here are some > example entries from my syslog: > > Jun 3 00:33:40 moebius kernel: [ 145.023201] cpufreq-core: target for CPU 0: 800000 kHz, relation 0 > Jun 3 00:33:47 moebius kernel: [ 114.838909] cpufreq-core: target for CPU 0: 1000000 kHz, relation 0 > Jun 3 00:33:47 moebius kernel: [ 114.838977] freq-table: request for target 1000000 kHz (relation: 0) for cpu 0 > Jun 3 00:33:47 moebius kernel: [ 92.161872] codec_semaphore: semaphore is not ready [0x1][0x700300] > Jun 3 00:33:52 moebius kernel: [ 97.433279] cpufreq-core: target for CPU 0: 1200000 kHz, relation 0 > Jun 3 00:33:58 moebius kernel: [ 66.352233] cpufreq-core: target for CPU 0: 1400000 kHz, relation 0 > Jun 3 00:34:08 moebius kernel: [ 85.547260] cpufreq-core: target for CPU 0: 1200000 kHz, relation 0 > Jun 3 00:34:16 moebius kernel: [ 211.791738] cpufreq-core: target for CPU 0: 800000 kHz, relation 0 > Jun 3 00:34:27 moebius kernel: [ 112.941898] cpufreq-core: target for CPU 0: 1000000 kHz, relation 0 > Jun 3 00:34:31 moebius kernel: [ 231.793121] cpufreq-core: target for CPU 0: 800000 kHz, relation 0 > Jun 3 00:34:41 moebius kernel: [ 147.122593] cpufreq-core: target for CPU 0: 1200000 kHz, relation 0 > Jun 3 00:34:42 moebius kernel: [ 123.906802] cpufreq-core: target for CPU 0: 1000000 kHz, relation 0 > Jun 3 00:34:46 moebius kernel: [ 251.342116] cpufreq-core: target for CPU 0: 800000 kHz, relation 0 > Jun 3 00:34:51 moebius kernel: [ 192.985214] cpufreq-core: target for CPU 0: 1000000 kHz, relation 0 > > The printk times are taken from sched_clock(), which now > varies depending on the cpu frequency. Without these patches, > the printk times appear to consistently increase at the right rate. > I'm not sure what other portions of the kernel are affected by > this (watchdogs firing, or other issues?). Yep, looks like something isn't right between sched_clock and the cpufreq changes. I'll let you know when I've sorted it out. Thanks for the great testing! -john