Re: [PATCH 13/23] generic/650: revert SOAK DURATION changes

Dave Chinner
2025-01-21T22:15:52Z

On Tue, Jan 21, 2025 at 08:00:27AM -0500, Theodore Ts'o wrote:
> On Tue, Jan 21, 2025 at 03:57:23PM +1100, Dave Chinner wrote:
> > I probably misunderstood how -n nr_ops vs --duration=30 interact;
> > I expected it to run until either were exhausted, not for duration
> > to override nr_ops as implied by this:
>
> There are (at least) two ways that a soak duration is being used
> today; one is where someone wants to run a very long soak for hours
> and where if you go long by an hour or two it's no big deals. The
> other is where you are specifying a soak duration as part of a smoke
> test (using the smoketest group), where you might be hoping to keep
> the overall run time to 15-20 minutes and so you set SOAK_DURATION to
> 3m.

check-parallel on my 64p machine runs the full auto group test in
under 10 minutes.

i.e. if you have a typical modern server (64-128p, 256GB RAM and a
couple of NVMe SSDs), then check-parallel allows a full test run in
the same time that './check -g smoketest' will run....

> (This was based on some research that Darrick did which showed that
> running the original 5 tests in the smoketest group gave you most of
> the code coverage of running all of the quick group, which had
> ballooned from 15 minutes many years ago to an hour or more. I just
> noticed that we've since added two more tests to the smoketest group;
> it might be worth checking whether those two new tests addded to thhe
> smoketest groups significantly improves code coverage or not. It
> would be unfortunate if the runtime bloat that happened to the quick
> group also happens to the smoketest group...)

Yes, and I've previously made the point about how check-parallel
changes the way we should be looking at dev-test cycles. We no
longer have to care that auto group testing takes 4 hours to run and
have to work around that with things like smoketest groups. If you
can run the whole auto test group in 10-15 minutes, then we don't
need "quick", "smoketest", etc to reduce dev-test cycle time
anymore...

> The bottom line is in addition to trying to design semantics for users
> who might be at either end of the CPU count spectrum, we should also
> consider that SOAK_DURATION could be set for values ranging from
> minutes to hours.

I don't see much point in testing for hours with check-parallel. The
whole point of it is to enable iteration across the entire fs test
matrix as fast as possible.

If you want to do long running soak tests, then keep using check for
that. If you want to run the auto group test across 100 different
mkfs option combinations, then that is where check-parallel comes in
- it'll take a few hours to do this instead of a week.

-Dave.
--
Dave Chinner
david@fromorbit.com