Eric Saxe wrote: > Mark Haywood wrote: >> Li, Aubrey wrote: >>> I guess Eric means P-state and C-state. >>> If so, _PSD describes P-State Dependency and _CSD describes C-state >>> Dependency. >>> >> >> Ah. Sorry. I'm familiar with the _CSD (and of course the _PSD), but >> didn't recognize what Eric was referring to. So, I assume that means >> _PSD defines the CPUs that share frequency change and C-state >> dependency defines the CPUs that share a voltage change? > Right, this is what I'm wondering as well (and I didn't know that _CSD > and _PSD described those two domains...is that really so?). > We can have the dispatcher consider thread placement across both > levels if that makes sense.
The _PSD domains define the CPUs that share P-state dependencies. P-states are really a combination of frequency and voltage scaling. The _CSD domains define the CPUs that share C-state dependencies. Do C-states really just equate to voltage scaling? I don't know. Aubrey or Bill might know. There are T-states (throttling) too. And they have domains defined by _TSD objects. I don't know if the dispatcher needs to know anything about them. Our only planned support for T-states is to allow for throttling in response to _TPC change notifications. Regardless, yes I think that the CPU Power Manager needs to abstract this info and make it available to the dispatcher to use. > > -Eric
