[ntp:questions] xntpd and Timekeeper

Miroslav Lichvar mlichvar at redhat.com
Mon Sep 10 10:45:37 UTC 2018

On 2018-09-03, Peter <dale.gilmore at gmail.com> wrote:
> When NTP version 4 is stopped and start NTP version 3 the figures look
> like (after running for ~1hr):

You may need to wait longer for things to settle down.

> # ntpq -p
>      remote           refid      st t when poll reach   delay   offset    disp
> +host1 .PTP.            1 u   27   64  377     0.99  -90.299    2.09
> +host2 .PTP.            1 u   14   64  377     0.11  -90.642    1.79
> -host3 .PTP.            1 u   11   64  377     1.34  -90.717    2.01
> *host4 .PTP.            1 u   49   64  337     0.09  -89.825    1.75
> With this host, the binary for ntpq is the same for xntp as for
> ntp…(ie the same binary is being used to produce both results above)
> Similar symptoms are noted for AIX and Solaris.

Does this happen also when you reset the kernel frequency with "ntptime
-f 0" before starting xntpd, or remove the drift file? I think it could
be due to a difference in how ntpd and xntpd are controlling the clock.
If xntpd didn't use the kernel discipline, it would need to correct for
the kernel frequency offset that was set by ntpd.

If that doesn't help, please enable the loopstats log and post it here
after xntpd has been running for at least a day. I doubt this is an
issue with the server.

Miroslav Lichvar

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