[ntp:questions] ntp too agressive on clock changes

David Taylor david-taylor at blueyonder.co.uk.invalid
Tue Apr 16 08:48:26 UTC 2013

On 15/04/2013 20:42, website.reader3 at gmail.com wrote:
> David:
> I need to study the loopstats more carefully, but I think that ntp is making about 0.6 millisecond corrections now at an irregular interval of some 1100 seconds.
> I think I found the culprit, it is the nanosleep() library routine call.
> Randall


Normally, NTP will not make step corrections unless the clock is out by 
more than 128 milliseconds (IIRC).  NTP alters the rate to bring the 
PC's clock into phase sync with the PPS signal.  I think you are using 
just the serial GPS data, and that can have quite a lot of jitter - 
often more jitter than an Internet source.  A local stratum-1 server is 
what's needed.

I don't understand your reference to nanosleep() - where is that routine 
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