[ntp:questions] Very large offset and jitter values after reboot

Unruh unruh-spam at physics.ubc.ca
Mon Aug 25 01:13:04 UTC 2008

nb at komeda-berlin.de (Nicola Berndt) writes:

>>>      remote           refid      st t when poll reach   delay   offset  
>>> jitter
>>> ==============================================================================
>>>  GPS_NMEA(0)     .GPS.            0 l    9   64   37    0.000  -580.75 
>>> 3965.19
>> You've not had your first 8 samples yet.  You haven't actually had 
>> enough for ntpd to act on the data.  You can speed that up with iburst, 
>> but ntpd will still take a long time to get a very tight lock.  jitter 
>> will reduce as you get to the eight samples.  The good? think, is that 
>> you are more than 128ms out, so that ntpd will step the time, to zero 
>> the offset, once it gets enough samples.

>Just tried the iburst option, but I had to figure it only works with the 
>server command, not on refclocks.

Oops forgot you have a gps clock. chrony does not work with refclocks.

>What really puzzles me, is the stoical 600 ms offset after rebooting. 
>Since it is always returning having more or less the same amount, I 
>should really be able to get rid of it, no?

It sounds like your rtc has problems. You can use hwclock to compensate for
rtc problems. 

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