What can be done with ntpd's code to address the lack of speed in ramping down the time constant as needed to keep up with changes in the local clock?
> You are observing on a time scale much shorter than the loop time > constant. ntpd has an adaptive time constant, and once it has gained > initial lock, that becomes quite long, as it assumes that offsets are > due to measurement errors, e.g. due to differential delays out and > return. Also, in your case, you may actually have been using the same > best sample for the whole 15 minutes. > > This strategy will generally give the best solution if the temperatures > of the oscillators are stable. Where ntpd can have problems is in not > ramping down the time constant fast enough if the temperature changes > and the local clock frequency changes. > > I'm not sure of the exact oversampling rate, but even after the > approximately 1 out of 8 sampling for the best of the last 8, I believe > it is still oversampling in relation to the loop time constant. > > _______________________________________________ > questions mailing list > questions@lists.ntp.org > http://lists.ntp.org/listinfo/questions _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
