[ntp:questions] Ginormous offset and slow convergance

unruh unruh at invalid.ca
Wed Nov 30 23:28:22 UTC 2011

On 2011-11-30, Miroslav Lichvar <mlichvar at redhat.com> wrote:
> On Wed, Nov 30, 2011 at 10:24:45PM +0000, unruh wrote:
>> If he has peerstats log file, he can look at it and see what teh offset
>> is of the oncore and the other ntp sources to see if it is really
>> misbehaving that badly. Also, if it is out by 16 sec, why in the world
>> has ntp not stepped the time? The threshold is 128ms. 
> I think it did step and more than once. I'd suspect a bug in the
> firmware in the GPS-UTC offset handling, current offset is 15 seconds
> and that is visible in one of the ntpq outputs in the original post.

But how could he get a 16 second offset, after starting out with a .1 s
and 1 s offset. At 500PPM, 16 sec takes 32000 sec  (10 hr) to accumulate
 which is poll interval 15. Ie, I cannot see how ntpd could have
 allowed that huge an offset to occur. 

In the posts I saw that all of the sources were off by 16 sec, not just
the Oncore. 

> Would be interesting to know if this happens on every ntpd restart or
> only shortly after the GPS unit was powered up.


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