Re: [PATCH v3 0/2] KVM: selftests: Reduce PMC test runtime by ~17x

[Sean Christopherson]

On Fri, Aug 07, 2026, Sean Christopherson wrote:
> On Tue, 04 Aug 2026 14:00:44 -0700, Sean Christopherson wrote:
> > Reduce the runtime of the PMU counters test on an Emerald Rapids system from
> > ~85 seconds to ~5 seconds by (a) testing one random GP counter in the arch
> > events test instead of every GP counter and (b) creating one large VM per
> > "major" test and then running each subtest with a different vCPUs, versus
> > creating a new single-vCPU VM for every subtest.
> > 
> > AFAICT, there aren't any bugs anywhere in the VM creation flow, there's just
> > a lot of work to be done.  And VM creation isn't even that slow, but creating
> > something like 1000+ VMs for the test adds up.
> > 
> > [...]
> 
> Applied to kvm-x86 selftests2, thanks!
> 
> [1/2] KVM: selftests: Test one random GP counter in PMU arch events testcase
>       https://github.com/kvm-x86/linux/commit/a53d1602e3bf
> [2/2] KVM: selftests: Create one VM with many vCPUs for each major PMU counters test
>       https://github.com/kvm-x86/linux/commit/f6e01d4fa1e8

Squashed a fixup for patch 2.  I meant to drop the unused perf_capabilities param
reported by Sashiko, but forgot to do so when applying.  New hash:

[2/2] KVM: selftests: Create one VM with many vCPUs for each major PMU counters test
      https://github.com/kvm-x86/linux/commit/4fe8b4e1545a