[time] Best attainable offset of ntpd?
Fri Jun 23 16:09:13 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?
That is about as good as you will get without replacing the crystal in
your machine with an ovenized one that is not sensitive to temperature
swings. With a standard crystal if you plot the frequency correction
NTP is applying you'll be able to see changes in machine load and room temp.
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