Re: [PATCH 1/2] selftests/kmod: increase the kmod timeout from 45 to 165

[Shuah Khan]

On 3/3/23 14:48, Luis Chamberlain wrote:
> On Fri, Mar 03, 2023 at 01:35:10PM -0700, Shuah Khan wrote:
> > On 2/27/23 15:42, Luis Chamberlain wrote:
> > > On Mon, Feb 27, 2023 at 03:32:50PM -0700, Shuah Khan wrote:
> > > > On 2/6/23 16:43, Luis Chamberlain wrote:
> > > > > The default sefltests timeout is 45 seconds. If you run the kmod
> > > > > selftests on your own with say:
> > > > >
> > > > > ./tools/testings/selftests/kmod.sh
> > > > >
> > > > > Then the default timeout won't be in effect.
> > > > >
> > > > > I've never ran kmod selftests using the generic make wrapper
> > > > > (./tools/testing/selftests/run_kselftest.sh -s) util now
> > > > > that I have support for it on kdevops [0]. And with that the
> > > > > test is limitted to the default timeout which we quickly run
> > > > > into. Bump this up to what I see is required on 8GiB / 8 vcpu
> > > > > libvirt q35 guest as can be easily created now with kdevops.
> > > > >
> > > > > To run selftests with kdevops:
> > > > >
> > > > > make menuconfig # enable dedicated selftests and kmod test
> > > > > make
> > > > > make bringup
> > > > > make linux
> > > > > make selftests-kmod
> > > > >
> > > > > This ends up taking about 280 seconds now, give or take add
> > > > > 50 seconds more more and we end up with 350. Document the
> > > > > rationale.
> > > > >
> > > > > [0] https://github.com/linux-kdevops/kdevops
> > > > > Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
> > > > > ---
> > > > >     tools/testing/selftests/kmod/settings | 4 ++++
> > > > >     1 file changed, 4 insertions(+)
> > > > >     create mode 100644 tools/testing/selftests/kmod/settings
> > > > >
> > > > > diff --git a/tools/testing/selftests/kmod/settings b/tools/testing/selftests/kmod/settings
> > > > > new file mode 100644
> > > > > index 000000000000..6fca0f1a4594
> > > > > --- /dev/null
> > > > > +++ b/tools/testing/selftests/kmod/settings
> > > > > @@ -0,0 +1,4 @@
> > > > > +# measured from a manual run:
> > > > > +# time ./tools/testing/selftests/kmod/kmod.sh
> > > > > +# Then add ~50 seconds more gracetime.
> > > > > +timeout=350
> > > >
> > > > Adding timeouts like this for individual tests increases the overall kselftest
> > > > run-time. I am not in favor of adding timeouts.
> > > >
> > > > We have to find a better way to do this.
> > >
> > > Well if folks don't have this the test will fail, and so a false
> > > positive. If the goal is to have a low time timeout for "do not run
> > > tests past this time and do not fail if we stopped the test" then
> > > that seems to be likely one way to go and each test may need to be
> > > modified to not fail fatally in case of a special signal.
> >
> > We are finding more and more that timeout values are requiring
> > tweaks. I am in favor of coming up a way to exit the test with
> > a timeout condition.
>
> OK so do we use the existing timeout as a "optional, I don't want my
> test to take longer than this" or "if this test takes longer than
> this amount this is a fatal issue"?

It isn't a fatal issue. So I wouldn't call it one. I would add a
message saying test timed out.

One way to handle this is:
- Add a test run-time option and have user tune it as needed.

Make the timeout an option so users can set it based on their
environments.

> I ask because right now we can't override it even with an environment
> variable. If we had such support we can let test runners (like kdevops)
> use selftests with its own set of qualified / verified timeouts for the
> VMs it uses.
>
> For instance, Iw ant to soon start asking 0day to enable my kdevops
> 0-day tests for the subsystems I maintain, but I can't do that yet as
> the timeout is not correct.

This test isn't part of the default run, so day has to run this as a
special case and it would make prefect sense to provide a tunable
timeout option.

thanks,
-- Shuah
>    Luis