ntpd flipping between PLL and FLL mode

[Jeremy Chadwick]

This issue has been discussed in the past, although no one
really concluded what the cause was, or if there were
implications from it:

http://www.mail-archive.com/freebsd-stable@freebsd.org/msg67325.html

http://lists.freebsd.org/pipermail/freebsd-questions/2004-September/059279.html

There's also a docs/ PR which may have implications in the
sense that "something changed" between ntpd versions:

http://lists.freebsd.org/pipermail/freebsd-doc/2006-October/011434.html

There's an open bug report with the NTP folks about this:

https://lists.ntp.isc.org/pipermail/bugs/2005-June/002174.html

I can reproduce this behaviour on 3 different boxes with
completely different hardware, all running 6.x.  Below, in
sequential order, are an AMD SMP box, a uni-proc Intel, and
an Intel SMP box.

Dec 19 00:22:26 icarus ntpd[624]: kernel time sync enabled 2001
Dec 19 01:47:48 icarus ntpd[624]: kernel time sync enabled 6001
Dec 19 02:04:52 icarus ntpd[624]: kernel time sync enabled 2001

Dec 19 01:51:07 eos ntpd[85369]: kernel time sync enabled 6001
Dec 19 02:08:10 eos ntpd[85369]: kernel time sync enabled 2001
Dec 19 03:33:34 eos ntpd[85369]: kernel time sync enabled 6001

Dec 18 18:29:38 medusa ntpd[99931]: kernel time sync enabled 2001
Dec 18 21:20:26 medusa ntpd[99931]: kernel time sync enabled 6001
Dec 18 21:37:32 medusa ntpd[99931]: kernel time sync enabled 2001

If this is completely normal behaviour, which many of the threads
above state it is (although in a couple instances there's examples
of the clock not being kept in sync while this is happening),
then there's the issue of how to disable this kind-of logging.

I looked at the ntpd code for this, and there does not appear to
be a way to disable logging of this message without impacting other
important ntpd messages.  :-(

So I guess my post here is to ask if anyone has extensive experience
with this, and what the implications are.  With ntpdate being phased
out soon, most people will be expected to run ntpd, and therefore
more support mails will be sent to the lists asking about this...

-- 
| Jeremy Chadwick                                 jdc at parodius.com |
| Parodius Networking                        http://www.parodius.com/ |
| UNIX Systems Administrator                   Mountain View, CA, USA |
| Making life hard for others since 1977.               PGP: 4BD6C0CB |