Hi,
Hoping someone smarter than I can help out here 🙂 I have a Meteor Lake machine which has the new P/E core architecture. I am trying to optimise a mobile platform for on-battery runtime and from the documentation I have read this requires CPUs to be in ACPI state C3 (which corresponds to platform state C10). Though I’ve enabled cpuidle (with the corresponding GRUB parameter) the issue I’m having is Xen will never enter C3 on any cores once there are a certain number of HVMs running (on my platform it is around 3-4), no matter which cores they are pinned to. For example, even if I pin the HVMs (and their corresponding device model stubdoms) to the E-cores, the P-cores will refuse to enter C3 and display 99.81% residency for C2. This happens regardless of the number of vCPUs allocated to the HVMs (I tested it with just one allocated) nor the workload (it is very light, with barely any CPU time shown).
If I fully pause or shut down the HVMs however, C3 jumps up to a much more reasonable residency. I am using sched-credit2 as the scheduler with default weight and cap values.
Would appreciate any input.
Best,
Alex
