[time-nuts] raspberry pi, adafruit gps & ntp

folkert folkert at vanheusden.com
Sat Jun 22 22:08:35 UTC 2013


Hello,

The last 25 hours I measured the jitter of my RPi-with-userspace PPS
processing. In the following graph you'll see those measurements. Each
row is an hour:
http://vps001.vanheusden.com/~folkert/jitter-hm.png
There's some kind of wave in it which I cannot explain: everything not
related to timekeeping (apart from sshd) is disabled on that device. No
cron, no at, not even the processes that monitor the state of the
network port.
Allan deviation: http://vps001.vanheusden.com/~folkert/allandev.png


Folkert van Heusden

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