Bill Holler wrote: > Mark Haywood wrote: >> 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. >> > > Are _CSD/c-state domains "flat", or can these be in a tree? > For example if there is a 4-core chip with two shared caches? > > I am having a hard time envisioning how the PAD will place > threads across both _PSD and _CSD defined domains. > Would the PAD prefer high p-state domains, and then > lower p-state domains, and then lower c-state domains last?
My guess is that the _CSD and _PSD domains will be identical. I think Aubrey will have a better idea. > > >> 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. >> > > Does software need to do the t-state throttling, or will > hardware do this for us? The _TPC change notifications > could be useful for c-state domain selection assuming c-states > are better than t-states for cooling. The OSPM needs to handle the _TPC change notification and then write a value to a register that tells the CPU to throttle. I could see where this information might be useful in scheduling selection. > > Bill > >> Regardless, yes I think that the CPU Power Manager needs to abstract >> this info and make it available to the dispatcher to use. >> >> >>> -Eric >>> >> >> _______________________________________________ >> tesla-dev mailing list >> tesla-dev at opensolaris.org >> http://mail.opensolaris.org/mailman/listinfo/tesla-dev >> >
