[ntp:questions] clockstats pausing during ntpq poll

A C agcarver+ntp at acarver.net
Fri Feb 17 06:06:17 UTC 2012


As part of my testing I'm observing the main log, peers, loops, and 
clockstats in one window while I observe ntpq (running on a different 
machine) polling the server every five seconds.  The PPS refclock has 
flag4 set so that clockstats are recorded.

What I've noticed is that normally the clockstats is updated once per 
second as the PPS ticks.  However, during a query by the remote ntpq 
instance, the clockstats file pauses for about one second and then 
resumes.  You can see it below in a direct copy from the clockstats 
file.  There's a missing 'tick' at 21828 seconds and one at 21832.  PPS 
is most certainly ticking at these times.  It is extremely obvious, when 
the two terminal windows are side by side, that the ntpq poll freezes ntpd.

> 55974 21822.994 127.127.22.0 -0.000033126
> 55974 21824.099 127.127.22.0 -0.000026711
> 55974 21825.994 127.127.22.0 -0.000010522
> 55974 21826.993 127.127.22.0 -0.000039330
> 55974 21827.994 127.127.22.0 -0.000019143
> 55974 21829.099 127.127.22.0 -0.000006765
> 55974 21830.993 127.127.22.0 -0.000023575
> 55974 21831.993 127.127.22.0 -0.000033386
> 55974 21833.102 127.127.22.0 -0.000004012




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