Please review this document fragment

Gary E. Miller gem at
Tue Nov 26 00:43:59 UTC 2019

Yo Sanjeev!

On Tue, 26 Nov 2019 07:15:30 +0800
Sanjeev Gupta via devel <devel at> wrote:

> The _GPSD_ man page suggests setting minpoll and maxpoll to 4.

I can find no such statement.  Can you locate that for me?

gpsd-time-service-howto.html says:

    "ntpd seems to better use a PPS refclock when the polling interval is
    as small as possible.  The ntpd default minpoll is 6, and can be set to
    as low as 4.  NTPsec versions 0.9.5 and above of ntpd allow you to
    set minpoll and maxpoll as low as 0.  Changing minpoll from 4 to 3, 2, 1
    or maybe even a,0 may reduce your PPS jitter by over a factor of 4."

    "It change may require several hours for ntpd to converge with the new
    settings.  Use ntpviz to find the best poll interval for your system."

    "The value that yields the lowest jitter may not be the one that yields
    the best Local Clock Frequency Offset."

My testing shows 3 or 4 works best, depending on many factors.

Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at  Tel:+1 541 382 8588

	    Veritas liberabit vos. -- Quid est veritas?
    "If you can't measure it, you can't improve it." - Lord Kelvin
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