Re: [PATCH v3 00/12] KVM: selftests: Add more syscall wrappers, fix hardware_disable_test

Yosry Ahmed <[email protected]> Fri, 31 Jul 2026 14:43:12 -0700
Newsgroups dev.linux.lists.kvmarm,org.infradead.lists.linux-arm-kernel,org.kernel.vger.kvm,org.kernel.vger.linux-kernel
Message-ID <CAO9r8zNmjinr53exDSwVKooosz1w2=4qexRF88u21AFwUpfFJQ@mail.gmail.com>
On Fri, Jul 31, 2026 at 2:41 PM Sean Christopherson <[email protected]> wrote:
>
> On Fri, Jul 31, 2026, Yosry Ahmed wrote:
> > On Fri, Jul 31, 2026 at 12:56 PM Sean Christopherson <[email protected]> wrote:
> > >
> > > Third time's a charm.  Sorry for the spam.
> > >
> > > Buried in the middle of this is a fix for the hardware_disable_test where
> > > it can end up with a runtime of multiple minutes when running a preemptible
> > > kernels on a large NUMA system.  Turns out my analysis/guess in v1 was wrong;
> > > the problem isn't direct CPU contention, it's that letting the workers do any
> > > amount of "real" work on any CPUs leads to pthread_create() slowdowns from
> > > the perspective of the caller.
> >
> > How long does the test take to run with this series?
>
> Less than 5 seconds if nothing else is running.  ~12 seconds if I run it
> concurrently with mmu_stress_test using default settings, and ~25 seconds if I
> run it on an overloaded system (naively running all selftests in parallel).

Cool, I will stop skipping it after this series lands then :)