Re: High Interrupt After 7.3 Upgrade

Hi Chris,

On Tue, May 30, 2023 at 8:59 AM Chris Cappuccio <chris@nmedia.net> wrote:

> Samuel Jayden [samueljaydan1994@gmail.com] wrote:
> > Hi again,
> >
> > Just for the record:
> > I've downgraded to OpenBSD 7.2 (reinstalled) and everything is working
> like
> > a charm again.
> > I don't know what is wrong with 7.3 but ipi interrupt rate is too much
> and
> > somehow OpenBSD performance is too bad..
> > Thanks for reading.
> >
>
> Sounds like you are using 'systat' to measure interrupts. This is a bug
> in systat was was fixed in 7.3. Here is Scott Cheloha's message from that
> fix:
>
> "systat(1): vmstat: measure elapsed time with clock_gettime(2) instead of
> ticks
>
> The vmstat view in systat(1) should not use statclock() ticks to count
> elapsed time. First, ticks are low resolution. Second, the statclock
> is sometimes randomized, so each tick is not necessarily of equal
> length. Third, we're counting ticks from every CPU on the system, so
> every rate in the view is divided by the number of CPUs. For example,
> on an amd64 system with 8 CPUs you currently see:
>
> 200 clock
>
> ... when the true clock interrupt rate on that system is 1600.
>
> Instead, measure elapsed time with clock_gettime(2). Use CLOCK_UPTIME
> here so we exclude time when the system is suspended. With this
> change we no longer need "stathz" or "hertz". We can also get rid of
> the anachronistic secondary clock failure test.
>
>
>
I'm not the OP, but that's interesting to me because I'm wondering if it's
why Prometheus'
node_exporter from packages is reporting wildly wrong CPU stats on 7.3 that
don't at all
match what you'd expect when comparing top/htop output? It was fine prior
to upgrading
to 7.3, but I've just left digging into it on the back burner due to other
priorities.

Thanks!
Mark