Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754844AbZCIUmz (ORCPT ); Mon, 9 Mar 2009 16:42:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752988AbZCIUmp (ORCPT ); Mon, 9 Mar 2009 16:42:45 -0400 Received: from 2605ds1-ynoe.1.fullrate.dk ([90.184.12.24]:35130 "EHLO shrek.krogh.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752685AbZCIUmo (ORCPT ); Mon, 9 Mar 2009 16:42:44 -0400 Message-ID: <49B57F3D.5030008@krogh.cc> Date: Mon, 09 Mar 2009 21:42:37 +0100 From: Jesper Krogh User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: john stultz CC: Thomas Gleixner , Linus Torvalds , Linux Kernel Mailing List , Len Brown Subject: Re: Linux 2.6.29-rc6 References: <49A6F39F.9040801@krogh.cc> <49A6FEE2.90700@krogh.cc> <1f1b08da0902261319k7a60d80xaafc1101facfd2d9@mail.gmail.com> <49A70B24.6090706@krogh.cc> <1235685269.6811.11.camel@localhost.localdomain> <1235687483.6811.26.camel@localhost.localdomain> <49A78C79.304@krogh.cc> <1235766936.7402.5.camel@localhost.localdomain> <49ABACA0.3090300@krogh.cc> <1236029277.7756.0.camel@localhost.localdomain> <49ACC853.8070205@krogh.cc> <1236110026.6068.18.camel@localhost> <49AD90E2.7050209@krogh.cc> <1236118969.6068.87.camel@localhost> <49AE9EA4.2080500@krogh.cc> <49AECA3B.5030503@krogh.cc> <1236193075.3793.63.camel@jstultz-laptop> <1236220759.6863.7.camel@localhost.localdomain> <1236221530.6863.9.camel@localhost.localdomain> In-Reply-To: <1236221530.6863.9.camel@localhost.localdomain> 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 Content-Length: 3392 Lines: 78 john stultz wrote: > On Wed, 2009-03-04 at 18:39 -0800, john stultz wrote: >> On Wed, 2009-03-04 at 10:57 -0800, John Stultz wrote: >>> On Wed, 2009-03-04 at 19:36 +0100, Jesper Krogh wrote: >>>> jk@quad12:~$ python drift-test.py 10.192.96.19 >>>> 04 Mar 19:27:10 offset: -0.157696 drift: -693.0 ppm >>>> 04 Mar 19:28:10 offset: -0.195134 drift: -625.098360656 ppm >>>> 04 Mar 19:29:10 offset: -0.232579 drift: -624.595041322 ppm >>>> 04 Mar 19:30:10 offset: -0.270021 drift: -624.408839779 ppm >>>> 04 Mar 19:31:11 offset: -0.307461 drift: -621.727272727 ppm >>>> 04 Mar 19:32:11 offset: -0.344903 drift: -622.185430464 ppm >>>> 04 Mar 19:33:11 offset: -0.382345 drift: -622.491712707 ppm >>>> 04 Mar 19:34:11 offset: -0.419794 drift: -622.727488152 ppm >>>> 04 Mar 19:35:11 offset: -0.457239 drift: -622.89626556 ppm >>> >>> Yea, so from this and the settled ntpdc -c kerninfo data before, we can >>> see that the drift is further out then the 500ppm NTP can handle. >>> >>> So with that at least confirmed, we can focus back on to the fast-pit >>> tsc calibration code. >>> >>> Ingo, Thomas: I'm missing a bit of the context to that patch, other then >>> just speeding up boot times, was there other rational for moving away >>> from the ACPI PM timer based calibration? >>> >>> Could we maybe add a quick test that the pit reads actually take the >>> assumed 2us max? Doing this maybe via the HPET/ACPI PM? >> Hey Jesper, >> >> Here's a very-hackish patch to see if the approach I'm considering >> might fix the issue you're hitting. Could you apply it, boot the kernel >> a few times and send me the following segments of the dmesg for each of >> those boots (the example below is from my test box)? >> >> tsc delta: 44418024 >> ref_freq: 3000100 pit_freq: 3000384 >> TSC: Fast PIT calibration matches PMTIMER. >> TSC: PIT calibration matches PMTIMER. 1 loops >> Detected 3000.045 MHz processor. Hi John. Patched into 2.6.28.7 .. First boot. [ 0.000000] tsc delta: 34203220 [ 0.000000] ref_freq: 2311825 pit_freq: 2310386 [ 0.000000] TSC: Fast PIT calibration matches PMTIMER. [ 0.000000] TSC: PIT calibration matches PMTIMER. 2 loops [ 0.000000] Detected 2311.877 MHz processor. Second boot: [ 0.000000] tsc delta: 34200313 [ 0.000000] ref_freq: 2311803 pit_freq: 2310190 [ 0.000000] TSC: Fast PIT calibration matches PMTIMER. [ 0.000000] TSC: PIT calibration matches PMTIMER. 2 loops [ 0.000000] Detected 2311.876 MHz processor. Third boot: [ 0.000000] tsc delta: 34198686 [ 0.000000] ref_freq: 2311824 pit_freq: 2310080 [ 0.000000] TSC: Fast PIT calibration matches PMTIMER. [ 0.000000] TSC: PIT calibration matches PMTIMER. 1 loops [ 0.000000] Detected 2311.872 MHz processor. Fourth boot: [ 0.000000] tsc delta: 34199433 [ 0.000000] ref_freq: 2311831 pit_freq: 2310130 [ 0.000000] TSC: Fast PIT calibration matches PMTIMER. [ 0.000000] TSC: PIT calibration matches PMTIMER. 2 loops [ 0.000000] Detected 2311.821 MHz processor. -- Jesper -- 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/