Re: NetBSD-current Time issues on RPI3

[Michael van Elst <mlelstv%serpens.de@localhost>]

On Sat, May 04, 2019 at 10:54:04AM +0100, Sad Clouds wrote:
> > Something is resetting the hardware system timer and the next timer
> > interrupt is issued when it reaches the old count again.
> 
> Yes this is 64-bit. If it happens again, I'll try disabling ntpd and
> see if that helps.

It doesn't.

It's not the clock that stops but the timer interrupts. In 64bit mode
we use the arm generic timers, these use a system wide 64bit counter
that just counts upwards after reset, each generic timer can cause
an interrupt when the system timer reaches some value. At each interrupt
we advance that threshold by an amount corresponding to 10ms.

When the system timer happens to be reset, it needs to count up again to the
threshold value to trigger the next interrupt. This takes as much time
as the machine was running after the last reset.



Greetings,
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."