[ntp:questions] Re: PPS source not always being chosen?

Hal Murray hmurray at suespammers.org
Mon Aug 15 02:09:12 UTC 2005

>I'm seeing a strange quirk in the selection process of my NTP servers
>that use refclocks that provide both a serial data timestamp as well as
>a PPS signal.  I mentioned this some time ago, and with the most recent
>4.2.0a-20050720 snapshot (running on FreeBSD 5.4), I'm still seeing the
>same thing.

>Attached below are the results of ntpq -p showing that the PPS source,
>while apparently far better in jitter and offset, is being deselected in
>preference to the serial timestamp source.  That just doesn't seem
>right.  Is there something in my configuration (sample attached below)
>that might be causing this?

I see similar things.

I think what's going on is that the sanity checking is believing the
remote clocks you are using and your local/good clock is getting
rejected because it's too far off from what the system thinks
is the right time.

Try commenting out the other clocks and see what happens.
Or maybe leave just one of them.

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