[Voyage-linux] Clock Drift

[Roel H]

Hello Robert,


Recently I made a patch to the kernel to use a 1024 Hz timer
frequency, based on the messages in this thread. This seems to
work well on the 2D2 board I have here. The clock is very stable
without ntp or adjtimex.

You can find my build of the 2.6.32-17 kernel at [1]. This is the
pure upstream kernel with added aufs and the 1024 Hz kernel
frequency (in the -geode image). So best use the -geode image on
the Alix.

Being a custom built upstream kernel it might not have all the
functionality you need, or break other things, but maybe it's
usefull to try whether the clock is any more stable.

If it's the case you might be able to patch the Voyage kernel
instead.

[1] http://zeus.ugent.be/~rulus/archive/experimental/experimental/

Kind regards,

Roel

Reply on message from Robert <Robert at supporttime.com>
received Thu 26 Aug 2010 18:41 +0200:
> Hello Guys,
> 
> I hope you're all well. I've been trying to resolve the clock
> drift issues again today and I'm struggling.
> 
> I cannot use the 'nomfgpt' work around as we rely on the
> watchdog and doing so breaks it.
> 
> I have installed adjtimex and ntp:
> 
> apt-get install adjtimex
> apt-get install ntp
> 
> Which I thought may solve the issue as some others have
> suggested but even with this the clock still drifts wildly, and
> after just a couple of hours the clock is already several
> minutes out of sync.
> 
> Can anyone offer any other advice? I could always schedule a
> cron task to correct the clock but that seems so hacky.
> 
> Thanks,
> 
> Robert
> 
> On 11/06/2010 03:28, "Darryl Ross" <spam at afoyi.com> wrote:
> 
> Really old thread, but wanted to say thanks, this has fixed the same
> problem I was having on 2x Alix2-3 systems.
> 
> 
> 
> Robert wrote:
> > Hi Jordi,
> >
> >
> >
> > That's a great help, thank you! I'll give that a go and see how I get on :-D
> >
> >
> >
> > Your wFrog sounds like an interesting project, do you do much work with
> > Thermometers and Hygrometer hardware? If so I've got a little pet
> > project on the go which I'd be interested to talk with you about! :-D
> >
> >
> >
> > Rob
> >
> >
> >
> > *From:* Jordi Puigsegur [mailto:jordi.puigsegur at gmail.com]
> > *Sent:* 26 February 2010 10:26
> > *To:* Robert
> > *Cc:* voyage-linux at list.voyage.hk
> > *Subject:* Re: [Voyage-linux] Clock Drift
> >
> >
> >
> > I run into the same problems a couple of weeks ago. First I tried
> > disabling mfgpt and it solved the problem but left the watchdog driver
> > not funcional. Later on I undid this change, activated again mfgpt and
> > installed adjtimex and ntp. My system is now working in perfect sync.
> >
> > I've described this configuration in a wiki
> > (http://code.google.com/p/wfrog/wiki/InstallOn_Alix3D2_voyageLinux0_6_2#Clock_sync).
> > wfrog is the open source weather logger I'm running on the Alix 3D2.
> >
> > Hope it helps!
> >
> > Jordi.
> >
> > 2010/2/26 Robert <Robert at supporttime.com <mailto:Robert at supporttime.com>>
> >
> > Hey Punky,
> >
> > Thanks for getting back to me. So you're saying I have a choice between
> > a working clock or a working watchdog, I can't have both?
> >
> > Robert
> >
> >
> > -----Original Message-----
> > From: Punky Tse [mailto:punkytse at punknix.com <mailto:punkytse at punknix.com>]
> > Sent: 26 February 2010 02:48
> > To: Robert
> > Cc: 'voyage-linux at list.voyage.hk <mailto:voyage-linux at list.voyage.hk>'
> > Subject: Re: [Voyage-linux] Clock Drift
> >
> > Hi Robert,
> >
> > Disabling mfgpt will make geode watchdog driver no functional.
> > [   22.373287] geodewdt:  No timers were available
> >
> > Regards,
> > Punky
> >
> > Robert wrote:
> >> Hi Punky, Thierry,
> >>
> >> Thanks very much for that suggestion. Tell me, is there any downside
> > to adding that boot parameter? is it likely to cause me other issues?
> >>
> >> Many thanks,
> >>
> >> Rob
> >> ________________________________________
> >> From: voyage-linux-bounces+robert=supporttime.com
> > <http://supporttime.com>@list.voyage.hk <http://list.voyage.hk>
> > [voyage-linux-bounces+robert=supporttime.com
> > <http://supporttime.com>@list.voyage.hk <http://list.voyage.hk>] On
> > Behalf Of Thierry MUSEUX - www.fwt.fr <http://www.fwt.fr> - [tm at fwt.fr
> > <mailto:tm at fwt.fr>]
> >> Sent: 25 February 2010 16:58
> >> To: 'voyage-linux at list.voyage.hk <mailto:voyage-linux at list.voyage.hk>'
> >> Subject: RE: [Voyage-linux] Clock Drift
> >>
> >> Hi,
> >>
> >> I have put in /boot/grub/menu.lst
> >> kernel /vmlinuz root=LABEL=ROOT_FS  console=ttyS0,38400n8 nomfgpt
> >>
> >> and in /etc/crontab
> >> 15 * * * * root /usr/sbin/ntpdate 0.fr.pool.ntp.org
> > <http://0.fr.pool.ntp.org> >> /dev/null 2>&1
> >>
> >> This solve the issue.
> >>
> >>
> >> Thierry Museux
> >> France Wireless Technologies
> >> www.fwt.fr <http://www.fwt.fr>
> >> msn: tm at fwt.fr <mailto:tm at fwt.fr>
> >> Tel: + 33 (0) 1 41 08 70 78
> >> Gsm: + 33 (0) 6 15 22 09 62
> >>
> >>
> >>
> >>
> >> -----Message d'origine-----
> >> De : voyage-linux-bounces+tm=fwt.fr <http://fwt.fr>@list.voyage.hk
> > <http://list.voyage.hk>
> >> [mailto:voyage-linux-bounces+tm
> > <mailto:voyage-linux-bounces%2Btm>=fwt.fr <http://fwt.fr>@list.voyage.hk
> > <http://list.voyage.hk>] De la part de Roel
> >> Huybrechts
> >> Envoyé : jeudi 25 février 2010 17:40
> >> À : Robert
> >> Cc : voyage-linux at list.voyage.hk <mailto:voyage-linux at list.voyage.hk>
> >> Objet : Re: [Voyage-linux] Clock Drift
> >>
> >> Hi Rob,
> >>
> >> Op donderdag 25-02-2010 om 08:26 uur [tijdzone -0800], schreef Robert:
> >>
> >>> Hello Guys,
> >>>
> >>> I've got some pretty serious clock drift on all the ALIX 3d2 which we've
> >>>
> >> got. Seems that after even just a short period of running the time on the
> >> systems is quite out of sync with the real time.
> >>
> >>> Is this a common issue? We've had it for a long time but I've only
> >>>
> >> recently sat down and tried to find a solution to the problem. Is this
> >> hardware related? or something software related?
> >>
> >>> Appreciate any advice you can offer.
> >>>
> >>> Rob
> >>>
> >>
> >> I've experienced the same issue on the ALIX 2d2 boards here. I've been
> >> able to greatly reduce the drift by installing the adjtimex package.
> >>
> >> Hope this helps for you as well.
> >>
> >> Regards
> >>
> >> --
> >> Roel Huybrechts
> >>
> >> GPG  | 4096R/5E2DE374
> >>      | http://rulus.be/gpg
> >>
> >>
> >> _______________________________________________
> >> Voyage-linux mailing list
> >> Voyage-linux at list.voyage.hk <mailto:Voyage-linux at list.voyage.hk>
> >> http://list.voyage.hk/mailman/listinfo/voyage-linux
> >>
> >> Support Time Managed Services - monitoring and development for entire
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> >>
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> >>
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> >>
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> >>
> >
> >
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> >
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> >
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> >
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> >
> >
> > ------------------------------------------------------------------------
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> >
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> >
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> > 1000 Lakeside North Harbour
> > Portsmouth PO6 3EZ United Kingdom
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