Mark Haywood wrote: > Eric Saxe wrote: >> Mark Haywood wrote: >> >>> Beautiful. Thanks for doing that. Anup and I just took a quick look >>> at the webrev and had a question about cpupm_num_groups() in >>> cpu_pm.c. We didn't understand the comment at the top of the >>> routine and weren't sure how to provide you with the "guts" for the >>> routine. >>> >> I was initially trying to provide for the possibility that there are >> multiple levels of CPU power management for a given CPU. For >> example, if we're able to quiesce an entire core, perhaps we'll drop >> the frequency...but if we can quiesce the socket, we (or at least >> the CPU) can also drop the voltage. This interface returns the >> number of "levels"...since the PG framework could create multiple >> levels of groupings to implement scheduling policy against... >> >> But I actually think I can get away with just having the second >> interface alone...please see below.. >> >> Does ACPI define distinct domains for logical CPUs which can share a >> frequency change, and logical CPUs which can share a voltage change? >> > > I assume that you are referring to P-state domains. If so, no the > P-state domains combine both frequency and voltage in the domain.
I guess Eric means P-state and C-state. If so, _PSD describes P-State Dependency and _CSD describes C-state Dependency. Thanks, -Aubrey
