[time] Best attainable offset of ntpd?

David J Taylor david-taylor
Fri Jun 23 08:55:43 UTC 2006

Philip M. White wrote:


What is the best offset that you have been able to attain with ntpd?
With a Garmin 18 LVC + LinuxPPS + Linux 2.6.17 + ntpd 4.20, the best I
can get is an offset of about 0.006 ms.  This offset is never steady --
it drifts from positive to negative.  Right *now*, for example, it is
-0.017 ms.  I use this machine for real work and play (X, multimedia,
OpenOffice, etc.).

My delay is consistently 0.000 ms, and jitter is 0.001-0.002 ms, so
those are good.  Is my offset good for a stratum-1 machine?  Can
anything be done to minimize and stabilize the offset?  Probably the key
factor is my activity on this machine, but is there anything else?


Here is what I get:


This is with FreeBSD on a very old 133MHz Pentium 1, with 48MB memory, 
dedicated just as a stratum 1 server.  It's not /that/ good, I know, and 
the GPS 18 LVC puck only has a view of half the sky (and less now the 
leaves have grown on the trees).

SatSignal software - quality software written to your requirements
Web:  http://www.satsignal.net
Email:  davidtaylor at writeme.com 

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