NTP Performance

Gary E. Miller gem at rellim.com
Sun Nov 24 02:19:15 UTC 2019


Yo Richard!

On Sat, 23 Nov 2019 01:53:33 -0600
Richard Laager via devel <devel at ntpsec.org> wrote:

> That trade-off makes sense to me. But, of the two, it seems like
> following the PPS closely is what I'd want. The PPS is supposed to be
> more accurate than my computer.

There is a gpsd program in the contrib/ directory.  It tests your
CPU granularity.  On a Raspberry Pi that is about 52 ns.  Worse
on an Intel chip.

> Now, if the computer is more accurate
> for short durations,

Never gonna happen with current CPUs.

The tradeoff is between time and frequency.  Short poll leads to more
"accurate" time.  Long poll leads to more "accurate" frequency.

ntpviz show this nicely.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at rellim.com  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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