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. > I think that a new --qemu_args would be generically useful for adhoc > use and light enough that people won't need to add qemu_configs much. > E.g. I can see people wanting multiple NUMA nodes, a specific -cpu, and so on.