✘sys_fuzz * ntp_random()

[Gary E. Miller]

Yo All!

Last week we had a discussion on sys_fuzz and the value of adding
random noise to some measurements.  The code defi2nes sys_fuzz asL

    "* The sys_fuzz variable measures the minimum time to read the system
     * clock, regardless of its precision."

Rondomness of half the sys_fuzz is then added to some values, like this:

    fuzz = ntp_random() * 2. / FRAC * sys_fuzz

Makes no sense to me.  Adding randomness helps when you have hysteresis,
stiction, friction, lash and some other things, but none of those apply
to NTP.

So I took two identical RasPi's and forced sys_fuzz to zero on one of
them.  Four days later I can see no difference in the results from
those two.

Can anyone find a case were adding the randomness can be proved to help?

We already have all the guesses we need, anyone have any data?

Otherwise sys_fuzz * ntp_random() is more poinltess noise in the code we
can rip out.

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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