Messages in this thread | | | Date | Thu, 17 Apr 2008 08:17:31 +0200 | From | "Bart Van Assche" <> | Subject | Re: AMD Quad Core clock problem? |
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On Wed, Apr 16, 2008 at 11:44 PM, Marc Perkel <mperkel@yahoo.com> wrote: > --- Bart Van Assche <bart.vanassche@gmail.com> wrote: > > It's better to correct the clock frequency once with > > the tickadj or adjtimex, so you don't have to add > > ntpdate to cron and you can still run ntpd. > > > > Bart. > > ok - thanks. How do I do that?
You can do that as follows: * First of all, make sure that adjtimex is installed. Some distro's include this command in util-linux. * Query the current tick value via adjtimex -p | grep tick. E.g. with HZ = 100, tick == 10000. * Multiply the tick value with the relative clock error: when e.g. 3s are lost every hour, the correct tick value is 10000 * (1 + 3/3600) = 10008. * Pass this new tick value to the kernel via adjtimex -t 10008. * Stop and restart ntpd such that it forgets any previous frequency estimates. * Keep an eye on the output of adjtimex -p|grep frequency to see whether the frequency estimate converges (should be stable within 10 ppm after an hour. See also man adjtimex for the units of this value).
Bart.
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