On Wed, May 18, 2022 at 8:36 AM Marco Elver <elver@xxxxxxxxxx> wrote: > > On Wed, 18 May 2022 at 17:31, Daniel Latypov <dlatypov@xxxxxxxxxx> wrote: > > > > On Wed, May 18, 2022 at 12:32 AM 'David Gow' via KUnit Development > > <kunit-dev@xxxxxxxxxxxxxxxx> wrote: > > > > > > Add a new QEMU config for kunit_tool, x86_64-smp, which provides an > > > 8-cpu SMP setup. No other kunit_tool configurations provide an SMP > > > setup, so this is the best bet for testing things like KCSAN, which > > > require a multicore/multi-cpu system. > > > > > > The choice of 8 CPUs is pretty arbitrary: it's enough to get tests like > > > KCSAN to run with a nontrivial number of worker threads, while still > > > working relatively quickly on older machines. > > > > > > > Since it's arbitrary, I somewhat prefer the idea of leaving up > > entirely to the caller > > i.e. > > $ kunit.py run --kconfig_add=CONFIG_SMP=y --qemu_args '-smp 8' > > > > We could add CONFIG_SMP=y to the default qemu_configs/*.py and do > > $ kunit.py run --qemu_args '-smp 8' > > but I'd prefer the first, even if it is more verbose. > > > > Marco, does this seem reasonable from your perspective? > > Either way works. But I wouldn't mind a sane default though, where > that default can be overridden with custom number of CPUs. > Ack. Let me clean up what I have for --qemu_args and send it out for discussion. One downside I see to adding more qemu_configs is that --arch now becomes more kunit-specific. Before, a user could assume "oh, it's just what I pass in to make ARCH=...". This new "--arch=x86_64-smp" violates that. I don't personally see it being that confusing, but I still worry.
