On a SNO VM running on OpenShift virtualization, the pmu is set as 'off' when the realtime is enabled: https://github.com/kubevirt/kubevirt/blob/main/pkg/virt-launcher/virtwrap/converter/vcpu/vcpu.go#L498-L509 
as a result the file /sys/devices/cpu/caps/pmu_name doesnot exist on the guest VM.

But tuned operator expected the file to exist so it can detect the CPU model to set the intel_pstate automatically: 
https://github.com/openshift/cluster-node-tuning-operator/blob/release-4.16/assets/performanceprofile/tuned/openshift-node-performance#L27 
https://github.com/redhat-performance/tuned/blob/master/tuned/profiles/functions/function_intel_recommended_pstate.py#L9 

Tuned profile got degraded in this case.

4.16.z, maybe other versions as well   

Always

1. Install SNO virtual machine on OpenShift virtualization 
2. Apply a performance profile and enable the realtime kernel
3. Check tuned profile status

Tuned profile got degraded

Tuned profile not degraded    

tuned logs:

2024-11-05 18:38:23,841 ERROR    tuned.utils.commands: Error when reading file '/sys/devices/cpu/caps/pmu_name': '[Errno 2] No such file or directory: '/sys/devices/cpu/caps/pmu_name''