[time] Best attainable offset of ntpd?
David J 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,
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
Email: davidtaylor at writeme.com
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