Yo Achim! On Tue, 28 Aug 2018 19:45:32 +0200 Achim Gratz via devel <devel@ntpsec.org> wrote:
> > The time from clock_gettime() is very coarse. Not up to our needs.
> > On a Raspberry Pi 3B+ running 64 bit kernel the granularity is only
> > 52 ns.
>
> That doesn't really matter, it is still about three orders of
> magnitude improvement over what we get today for the error that
> matters.
Ah no. Lukas says 200 ns. I can easily get under 1,000 ns. Sometimes
down to 400 ns with care. That is 2x, maybe 5x, certinaly not three
orders of magnitude. You'll have 3 orders of magnitude when you
get to 1 ns jitter. No consumer GPS can do that.
> We don't need to determine any interrupt latency when there's no such
> latency involved because we don't go through an interrupt for doing
> the measurement.
No need to keep beating that dead horse.
RGDS
GARY
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