[ntp:questions] Bug 2341 - ntpd fails to keep up with clock drift at poll>7

Brian Inglis Brian.Inglis at SystematicSw.ab.ca
Mon Dec 2 23:31:46 UTC 2013


On 2013-12-02 13:10, Harlan Stenn wrote:
> Brian Inglis writes:
>
>> When I ran current stable under Win 7 with only network servers I
>> found I had to drop minpoll to 4 (default is 6) so iburst would
>> quickly get a good offset and pull drift down from initial
>> out-to-lunch estimate compared to drift file contents.
>
> This is strange - iburst sends its polls at 2 second intervals, and with
> a good drift file will sync the clock in about 11 seconds' time.
>
> Dropping minpoll from 6 to 4 should only help if the initial conditions
> are "off" enough that the initial iburst volley didn't match up with
> things like the stored drift value.

Don't seem to have old network synched logs but with Win 7 current stable and ref clock,
I get the drift file load, then the out to lunch estimate 15 minutes later,
followed by clock_sync:

14 Aug 12:50:35 ntpd.exe[2708]: ntpd 4.2.6p5 at 1.2349-o Jul 30 11:55:08 (UTC+02:00) 2012  (2)
14 Aug 12:50:35 ntpd.exe[2708]: Raised to realtime priority class
14 Aug 12:50:39 ntpd.exe[2708]: 0.0.0.0 c012 02 freq_set ntpd 0.800 PPM
14 Aug 12:50:39 ntpd.exe[2708]: Using user-mode PPS timestamp for GPS_NMEA(4)
14 Aug 13:05:53 ntpd.exe[2708]: 0.0.0.0 c412 02 freq_set ntpd -1.183 PPM
14 Aug 13:05:53 ntpd.exe[2708]: 0.0.0.0 c415 05 clock_sync

18 Sep 21:10:29 ntpd.exe[2360]: Raised to realtime priority class
18 Sep 21:10:33 ntpd.exe[2360]: 0.0.0.0 c012 02 freq_set ntpd 0.850 PPM
18 Sep 21:10:34 ntpd.exe[2360]: Using user-mode PPS timestamp for GPS_NMEA(4)
18 Sep 21:26:02 ntpd.exe[2360]: 0.0.0.0 c412 02 freq_set ntpd 5.929 PPM
18 Sep 21:26:02 ntpd.exe[2360]: 0.0.0.0 c415 05 clock_sync

  3 Oct 18:37:01 ntpd.exe[3228]: Raised to realtime priority class
  3 Oct 18:37:05 ntpd.exe[3228]: Using user-mode PPS timestamp for GPS_NMEA(4)
  3 Oct 18:37:05 ntpd.exe[3228]: 0.0.0.0 c012 02 freq_set ntpd 0.850 PPM
  3 Oct 18:52:18 ntpd.exe[3228]: 0.0.0.0 c412 02 freq_set ntpd 1.448 PPM
  3 Oct 18:52:18 ntpd.exe[3228]: 0.0.0.0 c415 05 clock_sync

12 Oct 17:03:41 ntpd.exe[2968]: Raised to realtime priority class
12 Oct 17:03:45 ntpd.exe[2968]: 0.0.0.0 c012 02 freq_set ntpd 0.850 PPM
12 Oct 17:03:46 ntpd.exe[2968]: Using user-mode PPS timestamp for GPS_NMEA(4)
12 Oct 17:18:56 ntpd.exe[2968]: 0.0.0.0 c412 02 freq_set ntpd 6.215 PPM
12 Oct 17:18:56 ntpd.exe[2968]: 0.0.0.0 c415 05 clock_sync

14 Nov 16:56:15 ntpd.exe[2640]: Raised to realtime priority class
14 Nov 16:56:18 ntpd.exe[2640]: 0.0.0.0 c012 02 freq_set ntpd 0.875 PPM
14 Nov 16:56:20 ntpd.exe[2640]: Using user-mode PPS timestamp for GPS_NMEA(4)
14 Nov 17:11:40 ntpd.exe[2640]: 0.0.0.0 c412 02 freq_set ntpd -1.155 PPM
14 Nov 17:11:40 ntpd.exe[2640]: 0.0.0.0 c415 05 clock_sync

-- 
Take care. Thanks, Brian Inglis


More information about the questions mailing list