From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759756AbZBZWEZ (ORCPT ); Thu, 26 Feb 2009 17:04:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754164AbZBZWEQ (ORCPT ); Thu, 26 Feb 2009 17:04:16 -0500 Received: from 2605ds1-ynoe.1.fullrate.dk ([90.184.12.24]:42648 "EHLO shrek.krogh.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752977AbZBZWEP (ORCPT ); Thu, 26 Feb 2009 17:04:15 -0500 Message-ID: <49A711D3.8070001@krogh.cc> Date: Thu, 26 Feb 2009 23:04:03 +0100 From: Jesper Krogh User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: Thomas Gleixner CC: john stultz , Linus Torvalds , Linux Kernel Mailing List Subject: Re: Linux 2.6.29-rc6 References: <49A6F39F.9040801@krogh.cc> <49A6FEE2.90700@krogh.cc> <1f1b08da0902261319k7a60d80xaafc1101facfd2d9@mail.gmail.com> <49A70B24.6090706@krogh.cc> <1235684809.6811.5.camel@localhost.localdomain> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thomas Gleixner wrote: > On Thu, 26 Feb 2009, john stultz wrote: >> On Thu, 2009-02-26 at 22:35 +0100, Jesper Krogh wrote: >>> john stultz wrote: >>>> On Thu, Feb 26, 2009 at 12:43 PM, Jesper Krogh wrote: >>>>> Linus Torvalds wrote: >>>>>> On Thu, 26 Feb 2009, Jesper Krogh wrote: >>>>>>> 2.6.26.8 doesnt have this problem. >>>>>>> >>>>>>> The "current_clocsource" is the same on both systems. >>>>>>> >>>>>>> $ cat /sys/devices/system/clocksource/clocksource0/current_clocksource >>>>>>> tsc >>>>>> What does the frequency calibrate to? It should be in the dmesg. Does it >>>>>> differ by a big amount? >>>>> Non-working: >>>>> $ dmesg | grep -i freq >>>>> [ 0.004007] Calibrating delay loop (skipped), value calculated using >>>>> timer frequency.. 4620.05 BogoMIPS (lpj=9240104) >>>>> >>>>> 2.6.26.8 doesn't have that information. >>>> I'm surprised the clocksource watchdog isn't catching it. >>>> >>>> What's the output from: >>>> cat /sys/devices/system/clocksource/clocksource0/available_clocksource >>> $ cat /sys/devices/system/clocksource/clocksource0/available_clocksource >>> tsc acpi_pm jiffies >> Hmm. Does booting w/ "clocksourc=acpi_pm" also show the severe (~550ppm, >> which NTP can't handle) drift? >> >> >From the dmesg, I don't see any major calibration difference right off. >> >> So I'd suspect something like TSC halting in idle could be causing >> problems, but the watchdog should catch that as well. My only guess at >> this point is that the ACPI PM is halting in idle along with the TSC. > > But why would it do that on 29-rc6 and not on 2.6.28.8 ? I'm not aware > of changes which might cause that. My comparison is 2.6.26.8 not 2.6.28.8 .. so fairly old. It is a small cluster, so I'm slipping some test-kernels in when the cluster is idle. -- Jesper