[time-nuts] Noob question, NTP stratum 1.

[Achim Gratz]

Paul Theodoropoulos via time-nuts writes:
> I've also found that my Raspi's give the best results with board temp
> right around 60°C. However, I found that the 'CPU as heater', while it
> does help dramatically compared to nothing at all, it introduces a lot
> of jitter on its own. Much better results by keeping them in an
> insulated enclosure in a relatively stable location (for me, a
> closet!), and 'tuning' the insulation as needed to balance venting
> against retention.

Well, I have jitter (PPS timestamps) within ~2µs and the occasional
"hair" that goes out to about 30µs.  The distribution is a little bit
wider on the three systems that are loaded with extra server tasks, but
not much.  The thing to note is that you need to boot with "nohz=off",
set a fixed frequency as high as possible and use an interval timer for
controlling the CPU load (I use all four cores as workers and adjust
them at 40Hz).

[I can post plots, but at ~500kiB I think I should rather ask for
permission first.]


Regards,
Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+

Waldorf MIDI Implementation & additional documentation:
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