Re: perform_spin_delay() vs wait events

Hi,

On 2022-11-20 17:26:11 -0500, Robert Haas wrote:
> On Sun, Nov 20, 2022 at 3:43 PM Andres Freund <andres(at)anarazel(dot)de> wrote:
> > I couldn't quite decide what wait_event_type to best group this under? In the
> > attached patch I put it under timeouts, which doesn't seem awful.
>
> I think it would be best to make it its own category, like we do with
> buffer pins.

I was wondering about that too - but decided against it because it would only
show a single wait event. And wouldn't really describe spinlocks as a whole,
just the "extreme" delays. If we wanted to report the spin waits more
granular, we'd presumably have to fit the wait events into the lwlock, buffers
and some new category where we name individual spinlocks.

But I guess a single spinlock wait event type with an ExponentialBackoff wait
event or such wouldn't be too bad.

Greetings,

Andres Freund