[ntp:questions] Ref clocks and polling intervals

Chris Hastie chris at loopy.oak-wood.co.uk
Wed Nov 24 09:09:18 UTC 2004


About a year ago I raised an issue I was having whereby as soon as I
connected a ref clock the poll interval for all other sources dropped to
64s and stayed there.

A message from David Mills that I missed was recently brought to my
attention and as a result I upgraded to a dev version announcing itself
as 4.2.0 at 1.1179-r Wed Nov 17 16:04:21 GMT 2004 (1).

This has led to poll intervals rapidly reaching 1024s. But as David
points out in the message, it stiffens the PLL frequency and
consequently I'm seeing a marked diurnal oscillation of offset - the
machine is no where near air conditioned, in fact it's in a room that
the woodburner's chimney goes up through :( See <http://ntp.raggedstaff.
net/offsets2.php>

10 or 11 hours ago I set maxpoll to 8 on the reference clock in an
attempt to find a compromise. It's early, but it looks as if this may
have calmed down the daily swings a bit. But of course it's also
increased the frequency of polling to other sources.

Can anyone give me some hints as to what effects the following might
have:

1)  Reduce maxpoll for the reference clock to 6, but explicitly set it
    to 10 for all other sources.

2)  Reduce maxpoll for the reference clock to 6 but use a tinker maxpoll
    10 command

What I'm trying to achieve is a reduction in the daily swings whilst
still being a better neighbour than with a 64s poll interval to
everything.

-- 
Chris Hastie



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