Re: TS-7200: time sync issues

["M. Warner Losh" <imp%bsdimp.com@localhost>]

In message: <200812100249.mBA2nmB4029995%ginger.cmf.nrl.navy.mil@localhost>
            Ken Hornstein <kenh%cmf.nrl.navy.mil@localhost> writes:
: >> On my TS-7200, ntpd has some issues synchronizing the clock.
: >>[...]
: >Hmm...maybe I don't understand your problem, but I thought that was how 
: >ntpd worked.  When the clock isn't right, ntpd needs to both step the 
: >clock and possibly change the clock frequency.
: 
: Here's what's supposed to happen with ntpd.
: 
: 1) ntpd starts up
: 2) ntpd figures out how far the clock is off from real time
: 3) If clock offset > 128ms, then ntpd steps the time
: 4) As long as the clock offset is less then 128ms, ntpd adjusts the clock
:    frequency to keep things in sync.
: 
: Step 3 normally happens only once, at startup, because it's not hard
: to set the clock with 128ms accuracy.  But on the TS7200, that doesn't
: happen.  After the clock is set, the clock is _still_ off by an amount
: that varies from 100 to 900ms (that's what I've seen).  That is not normal
: ntpd behavior, and clearly something is wrong on ths TS7200.

What you are describing here is a frequency error.  ntpd adjusts both
the phase of the clock, and its frequency.  Usually the initial
inspection period is sufficient to get the initial estimate to within
a tens or hundreds of microseconds, and the frequency to with a ppm or
two (later it gets much better).  This means in the 1000s that your
logs showed the clock should have drifted on the order of maybe 1ms.
Instead, it drifted by 200ms, 100x too much.

Warner