Re: debugging functional tests that only fail in 'make check-functional'

[Peter Maydell <peter.maydell@linaro.org>]

On Fri, 21 Feb 2025 at 12:54, Thomas Huth <thuth@redhat.com> wrote:
>
> On 20/02/2025 19.39, Peter Maydell wrote:
> > Any suggestions for how to debug?
>
> Some TCG-based tests are slowing down very much when running on a shared hyperthreaded CPU ... Do you have 8 real cores in your system, or rather 4 real cores with 2 SMT threads each? In the latter case, have a try whether "make -j4" works better.

Yeah, it is a hyperthreaded 2-threads-per-core setup.
-j4 is a bit better but a few things still time out.
I'm currently playing with bumping the timeouts.

> > (Also the console.log is empty regardless of whether the
> > test passes or fails; this doesn't seem right.)
>
> I think we only log the console output when we look for strings
> in the output. Since this test does not look for any strings,
> there is no log.

That is very surprising to me. I think we should always
log all the guest output, because it's often an important
clue about why a test failed. (Ideally we'd log it in some
way that let you match up guest output with the logging
in base.log -- currently because of the split into three
different log files you can't tell what the relationship
is between e.g. QEMU stderr output and the test's progress
or the test progress and the guest console output.)

thanks
-- PMM