[ntp:questions] Re: Ref clocks and polling intervals

Richard B. Gilbert rgilbert88 at comcast.net
Thu Nov 25 00:09:10 UTC 2004

David L. Mills wrote:

> Chris,
> The reference clock poll interval is not intended to increase unless 
> you tell it to. That might be a bug; I'll look into it. However, just 
> about all the machines around here loaf at 1024 s without swinging 
> more than a couple of milliseconds. If yours are much greater than 
> that, including the reference clock, something else might be going on. 
> Set the maxpoll for the reference clock to 6 and leave the others 
> alone. You should see the same behavior as I.
> Dave
> Chris Hastie wrote:
>> 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.

I also see all my polling intervals drop to and remain at 64 seconds 
while my Motorola Oncore is reachable.  I believe I've mentioned this 
here earlier.  The Oncore is always polled at 16 second intervals.   I'm 
running 4.2.0 at 1.1161-r Sat Jan 31 23:24:32 EST 2004 (9).

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