David L. Mills wrote:
Richard,
You say the initial offset starts out at +90 ms and then "overshoots to
-9 ms". It can't do that; the PLL/FLL impulse response with default poll
interval crosses zero in about 3000 s, then <overshoots> about 6
percent. Even if you set the poll interval to the minimum 16 s, the zero
crossing would be about 750 s with identical overshoot.
What you describe looks like the clock is being set directly, not
disciplined by the PLL/FLL loop, or the adjtime() system call is broken,
as discussed previously. The discipline loop acts as a lowpass filter;
it cannot torque the offset "quickly" as you describe.
I do assume your ntpd code is relatively recent, like in the last year
or two. While some details of the ntpd initial training states have
changed in minor ways, the semi-linear PLL/FLL loop has been unchanged
for some time. The old xntpd code was seriously broken in this area and
displayed ntpq data that could be in serious error.
Dave
Richard B. Gilbert wrote:
David Woolley wrote:
In article <[EMAIL PROTECTED]>,
David L. Mills <[EMAIL PROTECTED]> wrote:
Pretty recent:
sunblok_$ ntpq -crv
assID=0 status=04c4 leap_none, sync_uhf_clock, 12 events,
event_peer/strat_chg,
version="ntpd [EMAIL PROTECTED] Wed Apr 26 20:16:54 EDT 2006 (1)",
processor="sun4u", system="SunOS/5.8", leap=00, stratum=1,
precision=-21, rootdelay=0.000, rootdispersion=0.371, peer=42873,
refid=GPS, reftime=c8dfa4cd.4c7f32bc Tue, Oct 17 2006 14:51:57.298,
poll=4, clock=c8dfa4d4.d4e8a36a Tue, Oct 17 2006 14:52:04.831, state=4,
offset=0.000, frequency=12.473, jitter=0.001, noise=0.001,
stability=0.000
I'll save the log file and the stats files the next time I'm forced to
restart it. We used to have almost monthly power outrages which
necessitated a a warm restart but a neighbor was persuaded to trim some
trees that were actually touching the power lines and it's been months
since the power went off!
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