[ntp:questions] Have Pi, have GPS = low powered NTP server?
hart at ntp.org
Thu Jun 7 16:01:01 UTC 2012
On Thu, Jun 7, 2012 at 10:30 AM, DaveB <g8kbv at uko2.co.uk> wrote:
> pi at raspberrypi:~$ ntpq -p
> remote refid st t when poll reach delay offset jitter
> *192.168.42.24 .GPS. 1 u 362 1024 377 0.563 0.669 0.284
> time.xilo.net 126.96.36.199 3 - 5h 1024 0 21.571 13.885 0.000
> dns0.rmplc.co 188.8.131.52 2 - 5h 1024 0 2019.75 -1000.8 0.000
> If those delay/offset and jitter figures are in milli seconds (?) could
> that be down to the USB hosted LAN port on the Pi? The same figures for
> the BSD box at 192.168.42.24 are 0.000 0.004 and 0.002 respectively, I
> just remoted into that and checked.
Yes, having your network behind a USB adapter is going to degrade
performance compared to a PCI-connected NIC. A half-millisecond delay
is quite high for 100Mbit LAN. Offset and jitter in the same range
are to be expected.
The output of:
ntpq -c "rv 0 version precision"
would shed a bit more light on which ntpd version and the time to read
the clock on that system.
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