Kernel NTP flipping between FLL and PLL modes

Andriy Gapon avg at
Wed Apr 6 03:48:08 PDT 2005

on 06.04.2005 11:13 Andriy Gapon said the following:
> I am using the default value of maxpoll, no overrides.
> So, IMO this leaves one possibility: mtemp > 2048, i.e. hardupdate() was
> not called for longer than this time i.e. either ntp_adjtime() was not
> called or it was called without MOD_OFFSET.
> It looks like it is not trivial to find the cause of this.

I can not explain it, but I've suddenly got a gut feeling that the
subject discussed might be a result of revision 1.53 of

Deal with MOD_FREQUENCY before MOD_OFFSET because the latter is the
one which runs the actual update.  This fixes a bug where there were
a delay in applying the frequency adjustment.  In extreme cases this
could result in marginal stability of the kernel-pll.

I can test this hypothesis as soon as I get a chance to reboot the
machine in question (might not be soon).

Andriy Gapon

More information about the freebsd-stable mailing list