From: Jesper Krogh <jesper@krogh.cc>
To: john stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Len Brown <len.brown@intel.com>
Subject: Re: Linux 2.6.29-rc6
Date: Mon, 09 Mar 2009 21:42:37 +0100 [thread overview]
Message-ID: <49B57F3D.5030008@krogh.cc> (raw)
In-Reply-To: <1236221530.6863.9.camel@localhost.localdomain>
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
next prev parent reply other threads:[~2009-03-09 20:42 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-23 4:31 Linux 2.6.29-rc6 Linus Torvalds
2009-02-23 14:07 ` Linux 2.6.29-rc6 - Fix oops in i915_gem_retire_requests Karsten Wiese
2009-02-26 11:15 ` Linux 2.6.29-rc6 Jesper Krogh
2009-02-26 17:17 ` MTD_CK804XROM warning (Was: Linux 2.6.29-rc6) Marcin Slusarz
2009-02-26 17:53 ` Linux 2.6.29-rc6 Linus Torvalds
2009-02-26 19:22 ` David Woodhouse
2009-02-26 19:31 ` Jesper Krogh
2009-02-26 19:36 ` David Woodhouse
2009-02-26 19:46 ` Jesper Krogh
2009-02-26 19:49 ` David Woodhouse
2009-02-26 20:53 ` Carl-Daniel Hailfinger
2009-02-26 20:32 ` Linus Torvalds
2009-02-26 19:55 ` Jesper Krogh
2009-02-26 20:33 ` Linus Torvalds
2009-02-26 20:43 ` Jesper Krogh
2009-02-26 21:19 ` john stultz
2009-02-26 21:35 ` Jesper Krogh
2009-02-26 21:46 ` john stultz
2009-02-26 21:54 ` Thomas Gleixner
2009-02-26 22:04 ` Jesper Krogh
2009-02-27 6:30 ` Jesper Krogh
2009-03-01 13:51 ` Jesper Krogh
2009-02-26 21:49 ` Linus Torvalds
2009-03-01 15:04 ` Jesper Krogh
2009-02-26 21:54 ` john stultz
2009-02-26 22:06 ` Thomas Gleixner
2009-02-26 22:24 ` Linus Torvalds
2009-02-26 22:31 ` Linus Torvalds
2009-02-26 22:31 ` john stultz
2009-02-26 22:40 ` Linus Torvalds
2009-02-26 22:59 ` john stultz
2009-02-27 7:33 ` Ingo Molnar
2009-02-27 20:50 ` john stultz
2009-02-27 6:47 ` Jesper Krogh
2009-02-27 20:35 ` john stultz
2009-03-01 20:13 ` Jesper Krogh
2009-03-02 9:53 ` Jesper Krogh
2009-03-02 21:27 ` john stultz
2009-03-03 6:04 ` Jesper Krogh
2009-03-03 19:53 ` john stultz
2009-03-03 20:19 ` Jesper Krogh
2009-03-03 22:22 ` john stultz
2009-03-04 15:30 ` Jesper Krogh
2009-03-04 18:36 ` Jesper Krogh
2009-03-04 18:57 ` John Stultz
2009-03-05 2:39 ` john stultz
2009-03-05 2:52 ` john stultz
2009-03-05 8:43 ` Ingo Molnar
2009-03-06 3:13 ` john stultz
2009-03-06 3:54 ` john stultz
2009-03-06 11:34 ` Ingo Molnar
2009-03-09 20:42 ` Jesper Krogh [this message]
2009-03-10 4:26 ` Linus Torvalds
2009-03-10 11:29 ` Thomas Gleixner
2009-03-10 19:42 ` Jesper Krogh
2009-03-10 22:22 ` Thomas Gleixner
2009-03-15 19:53 ` Jesper Krogh
2009-03-16 18:40 ` Jesper Krogh
2009-03-15 1:19 ` Linus Torvalds
2009-03-15 15:44 ` Jesper Krogh
2009-03-15 18:09 ` Linus Torvalds
2009-03-15 18:38 ` Jesper Krogh
2009-03-15 19:02 ` Linus Torvalds
2009-03-15 19:52 ` Jesper Krogh
2009-03-16 18:59 ` Jesper Krogh
2009-03-16 19:32 ` Linus Torvalds
2009-03-17 1:43 ` john stultz
2009-03-17 8:14 ` Ingo Molnar
2009-03-17 15:48 ` Linus Torvalds
2009-03-17 16:13 ` Ingo Molnar
2009-03-17 16:28 ` Linus Torvalds
2009-03-17 16:40 ` Ingo Molnar
2009-03-17 17:28 ` Olivier Galibert
2009-03-21 9:11 ` Jesper Krogh
2009-03-21 10:06 ` Ingo Molnar
2009-03-15 20:32 ` Linus Torvalds
2009-03-03 20:39 ` Jesper Krogh
2009-03-03 22:16 ` john stultz
2009-03-04 5:36 ` Jesper Krogh
2009-03-01 15:09 ` Jesper Krogh
2009-03-01 15:44 ` Linux 2.6.29-rc6 (clocksource) Sitsofe Wheeler
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=49B57F3D.5030008@krogh.cc \
--to=jesper@krogh.cc \
--cc=johnstul@us.ibm.com \
--cc=len.brown@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).