[ntp:questions] ntpd goes into oscillation

Richard B. Gilbert rgilbert88 at comcast.net
Wed Dec 30 19:06:52 UTC 2009

unruh wrote:
> ntpd has suddenly broken out into oscillations. it is fed by a Garmin
> 18 LVC PPS via shm. The oscillation has a period of just under an hour (
> about 50 min) and an amplitude of about 10usec. in the offsets (
> amplitude of about .005PPM in the rate). Since this is acting as the
> clock for a number of other machines, they are also showing the
> oscillation especially in the rate.
> While I suppose this could be something in the GPS itself, it looks more
> like an oscillation in ntpd. 
> Nothing changed when the oscillations started. Ntpd had been started
> on Dec 14, and this change began on Dec24. 
> You can see the graph on www.theory.physics.ubc.ca/chrony/chrony.html ,
> the graph for the machine called string. 
> Has anyone else ever seen this kind of thing?

You could get a better answer by supplying better information!

Your message did not mention what hardware platform you are running ntpd 
on nor the operating system, the versions of the O/S and NTPD, etc, etc!

The contents of ntp.conf are important but you have neglected to post 
this as well.

Please see http://www.catb.org/~esr/faqs/smart-questions.html
and try again.

More information about the questions mailing list