Re: High Interrupt After 7.3 Upgrade

On 2023-05-31, Mark (obsd) <openbsd-list@nerdish.us> wrote:
> 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.

That's a different issue, it was fixed in -current - I've just merged it to
-stable so updated packages should show up in a day or two.