Re: PSA: Clock drift and pkgin

[Anders Magnusson <ragge%tethuvudet.se@localhost>]

Den 2023-12-14 kl. 00:34, skrev Johnny Billquist:
> I would agree with all your observations and comments, Maciej. And it 
> reminded me that I have indeed observed quite some jitter in the past 
> myself.
>
> So it would seem to not be a simple case of lost interrupts, because 
> that should not be possible for the clock to run fast from.
>
> One hour over 100 days is a deviation of about 2%. I think that is 
> possible, but it wouldn't explain the jitter.
>
> As for the high frequency clock in the VAX, I'm not sure it is used at 
> all by NetBSD. But it's been quite a while since I was digging around, 
> and if someone knows it is being used, I'd be happy to hear. But I 
> think we have several problems that should be sorted. And for me, the 
> first one would be to understand how on earth we can be spending so 
> much time in system mode when we do anything.
I'm quite sure that all VAXen that have a hires clock uses it in time 
difference calculations.
There are two of them; the ICR version and the clock chip version. See 
clock.c for more info.

-- R