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McKenney wrote: [...] > Although that doesn't help on my laptop, it does work on my x86 test > system. Is the laptop a hybrid CPU, with P-cores and E-cores? KVM gives its guests no PMU on those. kvm_init_pmu_capability() in arch/x86/kvm/pmu.c clears enable_pmu under X86_FEATURE_HYBRID_CPU. > Perhaps something like the following would be helpful in keeping this > well-tested? Yes, that would help. Three comments on the patch: [...] > + qemu_args='--qemu-args "-cpu host,pmu=on"' [...] > + --configs "SRCU-P" ${qemu_args} --trust-make 1) The quotes inside the variable stay literal. The expansion is split on spaces, so kvm.sh gets three words: --qemu-args "-cpu host,pmu=on" A kvm.sh --dryrun with these arguments stops with: --qemu-args (qemu arguments) ""-cpu" must match "^-" Keeping only the value in the variable works: qemu_arg="-cpu host,pmu=on" [...] --configs "SRCU-P" ${qemu_arg:+--qemu-args "$qemu_arg"} --trust-make It expands to two words when set, and to nothing when empty. I checked it with kvm.sh --dryrun only. 2) nmi_readers and nmi_calls both default to true. So the two boot arguments change nothing. They are fine if you want them explicit. 3) The "atomic-srcu" run just above also runs readers in NMI, by default. It still starts without a PMU, so it keeps printing the "went untested" lines. It could take the same qemu argument. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com