timekeeping issues

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

My main g4 mini seems to be struggling with keeping time and has been
for ages.  After a reboot it keeps time just fine for days (with ntpd
running).  Then at some point it just falls apart and starts losing
time steadily (like, a few minutes a day).  This time round I kept an
eye on it, to see when it's gonna start doing that and it took about
20 days.  Nothing interesting in the logs.

When restarted, ntpd complains:

Dec 25 12:06:29 snips ntpd[18464]: kernel reports TIME_ERROR: 0x6041: Clock Unsynchronized

Anything I can do to debug (and hopefully fix) this?  The behavior is
reproducible, but as you can see it takes weeks for it to manifest.
Some 32-bit counter overflows?

NetBSD snips 10.0_STABLE NetBSD 10.0_STABLE (GENERIC) #0: Mon Jul  8 16:08:11 MSK 2024  uwe@majava:/home/uwe/work/netbsd/cvs/src-release-10/sys/arch/macppc/compile/GENERIC macppc

(hmm, probably needs a refresh anyway... :)

TIA

-uwe