On Thu, May 19, 2022 at 1:11 PM Daniel Latypov <dlatypov@xxxxxxxxxx> wrote: > > On Thu, May 19, 2022 at 6:15 AM David Gow <davidgow@xxxxxxxxxx> wrote: > > > > I tend to agree that having both would be nice: I think there are > > enough useful "machine configs" that trying to maintain, e.g, a 1:1 > > mapping with kernel architectures is going to leave a bunch of things > > on the table, particularly as we add more tests for, e.g., drivers and > > specific CPU models. > > I agree that we don't necessarily need to maintain a 1:1 mapping. > But I feel like we should have a pretty convincing reason for doing > so, e.g. support for a CPU that requires we add in a bunch of > kconfigs. Agreed. That being said, if we have a good convention for archs that are not in arch/, then it should be OK. The biggest thing is that all archs passed into ARCH=, if supported, should have a default with the same value for kunittool; as long as that is the case, I don't think anyone will get confused. > This particular one feels simple enough to me. > Given we already have to put specific instructions in the > kcsan/.kunitconfig, I don't know if there's much of a difference in > cost between these two commands > > $ ./tools/testing/kunit/kunit.py run --kunitconfig=kernel/kcsan > --arch=x86_64-smp > $ ./tools/testing/kunit/kunit.py run --kunitconfig=kernel/kcsan > --arch=x86_64 --kconfig_add CONFIG_SMP=y --qemu_args "-smp 8" Also agree. > I've generally learned to prefer more explicit commands like the > second, even if they're quite a bit longer. I agree, but I think I learned this from you :-) > But I have the following biases > * I use FZF heavily, so I don't re-type long commands much Same. > * I'm the person who proposed --kconfig_add and --qemu_args, so of > course I'd think the longer form is easy to understand. > so I'm not in a position to object to this change. Yeah, I think I am a bit biased on this too, but I don't terribly care one way or the other. > Changing topics: > Users can overwrite the '-smp 8' here via --qemu_args [1], so I'm much > less worried about hard-coding any specific value in this file > anymore. > And given that, I think a more "natural" value for this file would be "-smp 2". > I think anything that needs more than that should explicitly should --qemu_args. > > Thoughts? If we have time, we could bring this topic up at LPC? > [1] tested with --qemu_args='-smp 4' --qemu_args='-smp 8' > and I see the following in the test.log > smpboot: Allowing 8 CPUs, 0 hotplug CPUs > so QEMU respects the last value passed in, as expected. > > > > > The problem, of course, is that the --kconfig_add flags don't allow us > > to override anything explicitly stated in either the kunitconfig or > > qemu_config (and I imagine there could be problems with --qemu_config, > > too). > > This patch would fix that. > https://lore.kernel.org/linux-kselftest/20220519164512.3180360-1-dlatypov@xxxxxxxxxx > > It introduces an overwriting priority of > * --kconfig_add > * kunitconfig / --kunitconfig > * qemu_config
