Bill Holler wrote: > On 10/09/08 12:32, Bill Holler wrote: >> This is a great start. >> >> It would be really helpful if the hardware could export >> multiple levels of C-State power-dependency domains >> such as domains for each C-State (C2, C3, etc). >> The PAD can do a much better job scheduling if it is aware >> > > We would also like to have idle policies based on the state > the other CPUs within an idle CPU's multiple dependency domains. > For example an idle CPU might decide to go into C2 instead of C3 > if other CPU(s) in its C3 dependency domain are almost always > active but other CPU(s) in its C2 dependency domain are often idle. > > >> of these multiple levels. The current implementation >> appears to be missing the equivalence of a C3 dependency domain. >> >> Regards, >> Bill
Yes, if BIOS could export C-state denpendency, that would be helpful to idle policy. Does SUN's server support or planning to support _CSD? Otherwise we have to keep the current implementation first. All logical processors use the same VR are in the same domain and all transitions are to the same c-state(HW_ALL). Actually the processors in the same C2 domain are in the same C3 domain. I think this is also help to save power once we support CMT_COALESCE. Scheduler will try to schedule the new task to the same group so that the processors in another group can sleep longer and deeper. Regards, -Aubrey
