Because it's not a bug. There are different ways of controlling clock
adjustments (Phase Locked Loop vs Frequency Locked Loop), and the
FreeBSD kernel will switch between them depending on how often adjtime()
is being invoked. The only real issue is that logging about it can be
annoying, but I think newer versions of ntpd have changed the log level
to only display the message if debugging is enabled. See:
https://support.ntp.org/bugs/show_bug.cgi?id=452
http://www.ece.udel.edu/~mills/database/papers/nano/nano.pdf
"In operation, PLL mode is preferred at small update intervals and time
constants and FLL mode at large intervals and time constants. The
optimum crossover point between the PLL and FLL modes, as determined by
simulation and analysis, is the Allan intercept. As a compromise, the
PLL/FLL algorithm operates in PLL mode for update intervals of 256 s and
smaller and in FLL mode for intervals of 1024 s and larger. Between 256
s and 1024 s the mode is specified by the API. This behavior parallels
the NTP daemon behavior, except that in the latter the weight given the
FLL prediction is linearly interpolated from zero at 256 s to unity at
1024 s."
Regards,
--
-Chuck
Thanks, Chuck, you learn something every day!
Cheers,
David
_______________________________________________
questions mailing list
[email protected]
http://lists.ntp.org/listinfo/questions
