NTP Performance

Hal Murray hmurray at megapathdsl.net
Thu Nov 21 07:15:39 UTC 2019


> Why does ntp1 have this very specific repeating pattern of local clock
> offset? It's roughly +7 us, -5 us, +2 us, -4 us and then repeats again, over
> and over.

That's pretty weird.

> ntp1 uses the PPS refclock with a polling interval of 3 from a telecom GPSDO
> (OCXO): 

What brand/model?

------------

I don't have any good ideas.

The easy thing to try is changing the polling interval.

The next step would be to grab the PPS info and graph it.  Try this:
  http://users.megapathdsl.net/~hmurray/ntpsec/grab-pps.py
Grab it on ntp2 too so you have a reference.

Grabbing the PPS is "interesting".  Where are you standing?  If you turn off 
ntpd, the clock will be stable but may be drifting.  You can remove the drift 
when making the graph.


-- 
These are my opinions.  I hate spam.





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