[ntp:questions] Sudden change in precision and jitter

Harlan Stenn stenn at ntp.org
Sun Jun 2 00:47:17 UTC 2013

A C writes:
> NetBSD 5.1 (sparc)


> That would be interesting since I have a cron job restarting it at an 
> odd hour away from any other cron jobs left.  I'll check and see if 
> there are any others that I missed and then move the restart somewhere 
> if there's an overlap.

See ntp_proto.c:measure_precision() .

> I wish I could figure out how 4.2.6 and 4.2.7 differ in the calculations 
> because under 4.2.6 my jitter is always 0.061 while under 4.2.7 it is 
> always 0.122 no matter what I do.

There may be more changes in this area soon, as part of the fix for bug

And you can bring up the source file in question in a web browser
pointed at bk.ntp.org and see the changes that way - you should be able
to bring up the different changed versions.

> On 6/1/2013 17:01, Harlan Stenn wrote:
> > What OS?
> >
> > I'm guessing that when ntpd started this time the calculation loop took
> > a bit longer than before and that caused your precision to get a notch
> > worse, which triggered the doubling of the base jitter.
> >
> > H
> >
> >

More information about the questions mailing list