Re: [PATCH v3 2/2] tests/9pfs: fix test dir for parallel tests

[Greg Kurz <groug@kaod.org>]

On Sun, 01 Nov 2020 20:14:16 +0100
Christian Schoenebeck <qemu_oss@crudebyte.com> wrote:

> On Sonntag, 1. November 2020 18:44:44 CET Greg Kurz wrote:
> > On Sun, 1 Nov 2020 15:37:12 +0100
> > 
> > Christian Schoenebeck <qemu_oss@crudebyte.com> wrote:
> > > Use mkdtemp() to generate a unique directory for the 9p 'local' tests.
> > > 
> > > This fixes occasional 9p test failures when running 'make check -jN' if
> > > QEMU was compiled for multiple target architectures, because the
> > > individual
> > > architecture's test suites would run in parallel and interfere with each
> > > other's data as the test directory was previously hard coded and hence the
> > > same directory was used by all of them simultaniously.
> > > 
> > > This also requires a change how the test directory is created and deleted:
> > > As the test path is now randomized and virtio_9p_register_nodes() being
> > > called in a somewhat undeterministic way, that's no longer an appropriate
> > > place to create and remove the test directory. Use a constructor and
> > > destructor function for creating and removing the test directory instead.
> > > Unfortunately libqos currently does not support setup/teardown callbacks
> > > to handle this more cleanly.
> > > 
> > > The constructor functions needs to be in virtio-9p-test.c, not in
> > > virtio-9p.c, because in the latter location it would cause all apps that
> > > link to libqos (i.e. entirely unrelated test suites) to create a 9pfs
> > > test directory as well, which would even break other test suites.
> > > 
> > > Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> > > ---
> > 
> > Reviewed-by: Greg Kurz <groug@kaod.org>
> 
> Thanks for the overtime, on a Sunday!
> 
> Queued on 9p.next:
> https://github.com/cschoenebeck/qemu/commits/9p.next
> 
> And this one with Peter Xu's patches on top, just for testing:
> https://github.com/cschoenebeck/qemu/commits/9p.experimental.2
> 
> > I could run 'make check -j' with 4 archs (ppc64, x86_64, aarch64, s390x)
> > on a POWER9 system with 128 cpus, for ~1 hour without seeing any failure.
> > 
> > Tested-by: Greg Kurz <groug@kaod.org>
> 
> OO Sounds like having advantages working for IBM. Respect. I start to get envy 
> as these beasts are running towards PCIe 6, while we regular x86 users would 
> already be glad having PCIe 4.
> 

I work for Red Hat now but yes, this allows easier access to bigger systems.

> I give it some more spinning hours this time, just to be sure, before sending 
> the PR tomorrow morning. But I think it's all right now.
> 

Cool ! :)

> Thanks!
> 
> Best regards,
> Christian Schoenebeck
> 
>