Re: [PATCH net 1/3] selftests: tc: set timeout to 15 minutes

[Pedro Tammela]

On 13/07/2023 23:25, shaozhengchao wrote:
> On 2023/7/14 5:16, Matthieu Baerts wrote:
> > When looking for something else in LKFT reports [1], I noticed that the
> > TC selftest ended with a timeout error:
> >
> >    not ok 1 selftests: tc-testing: tdc.sh # TIMEOUT 45 seconds
> >
> > The timeout had been introduced 3 years ago, see the Fixes commit below.
> >
> > This timeout is only in place when executing the selftests via the
> > kselftests runner scripts. I guess this is not what most TC devs are
> > using and nobody noticed the issue before.
> >
> > The new timeout is set to 15 minutes as suggested by Pedro [2]. It looks
> > like it is plenty more time than what it takes in "normal" conditions.
> >
> > Fixes: 852c8cbf34d3 ("selftests/kselftest/runner.sh: Add 45 second 
> > timeout per test")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Link: 
> > https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20230711/testrun/18267241/suite/kselftest-tc-testing/test/tc-testing_tdc_sh/log [1]
> > Link: 
> > https://lore.kernel.org/netdev/0e061d4a-9a23-9f58-3b35-d8919de332d7@xxxxxxxxxxxx/T/ [2]
> > Suggested-by: Pedro Tammela <pctammela@xxxxxxxxxxxx>
> > Signed-off-by: Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx>
> > ---
> >   tools/testing/selftests/tc-testing/settings | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/tools/testing/selftests/tc-testing/settings 
> > b/tools/testing/selftests/tc-testing/settings
> > new file mode 100644
> > index 000000000000..e2206265f67c
> > --- /dev/null
> > +++ b/tools/testing/selftests/tc-testing/settings
> > @@ -0,0 +1 @@
> > +timeout=900
> I remember last year when I tested all the tdc cases（qdisc + filter +
> action + infra） in my vm machine, it took me nearly 20 minutes.
> So I think it should be more than 1200 seconds if all cases need to be
> tested.
>
> Maybe we should really optimize the parallel execution process of tdc.

Let's try to spend some cycles improving the tdc code performance first.
TDC boils down essentially to:
- Setup namespace (if needed)
- Setup network interfaces
- Spawn a few processes
- Match a regex
- Bring down namespace

Nothing above screams expensive, so I'm sure there are some low hanging 
fruits to improve the overall wall time even in debug kernels.