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> > > > static cpumask_var_t amu_fie_cpus; > > > > > > > > +/* > > > > + * Switching the active PE on an NVIDIA Olympus SMT core can keep the core in > > > > + * two-thread active mode, with resources partitioned between the PEs. > > > > + * > > > > + * Prefer PE0 so PE1 can remain idle and the core can stay in full-resource > > > > + * mode. Firmware does not currently describe this preference, so detect > > > > + * Olympus by MIDR until a firmware interface is available. > > > > + */ > > > > > > Fix the firmware? > > > > > > If we add this MIDR kludge, I guarantee that it will never be fixed. > > > > Understood. The existing PPTT already describes the SMT relationship, but as far > > as I can tell ACPI doesn't currently provide a way to describe a preferred SMT > > sibling. Both PEs also have equal isolated performance, so representing this > > using different _CPC highest_perf values wouldn't accurately describe their > > capacity. > > > > I'll drop the MIDR-based enablement and coordinate with the firmware team on a > > proper ABI. > > Thanks, Andrea, I must confess that I wasn't expecting that! I try to be a good citizen every now and then. :) > > > In the meantime, for systems with the existing firmware, would an explicit > > kernel boot option be acceptable as a fallback? It'd enable SD_ASYM_PACKING at > > the SMT level and prefer the primary PE, but only when requested by the user; > > the kernel would not infer this policy from the CPU model. > > I'm ok with that. Awesome! I'll work through Dietmar's point for this and post a new version without the MIDR-based detection. Thanks, -Andrea