Hi, On Tue, Sep 15, 2020 at 1:55 PM Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> wrote: > > On 15/09/2020 19:58, Matthias Kaehlcke wrote: > > On Tue, Sep 15, 2020 at 07:50:10PM +0200, Daniel Lezcano wrote: > >> On 15/09/2020 19:24, Matthias Kaehlcke wrote: > >>> +Thermal folks > >>> > >>> Hi Rajendra, > >>> > >>> On Tue, Sep 15, 2020 at 11:14:00AM +0530, Rajendra Nayak wrote: > >>>> Hi Rob, > >>>> > >>>> There has been some discussions on another thread [1] around the DPC (dynamic-power-coefficient) values > >>>> for CPU's being relative vs absolute (based on real power) and should they be used to derive 'real' power > >>>> at various OPPs in order to calculate things like 'sustainable-power' for thermal zones. > >>>> I believe relative values work perfectly fine for scheduling decisions, but with others using this for > >>>> calculating power values in mW, is there a need to document the property as something that *has* to be > >>>> based on real power measurements? > >>> > >>> Relative values may work for scheduling decisions, but not for thermal > >>> management with the power allocator, at least not when CPU cooling devices > >>> are combined with others that specify their power consumption in absolute > >>> values. Such a configuration should be supported IMO. > >> > >> The energy model is used in the cpufreq cooling device and if the > >> sustainable power is consistent with the relative values then there is > >> no reason it shouldn't work. > > > > Agreed on thermal zones that exclusively use CPUs as cooling devices, but > > what when you have mixed zones, with CPUs with their pseudo-unit and e.g. a > > GPU that specifies its power in mW? > > Well, if a SoC vendor decides to mix the units, then there is nothing we > can do. I mean, there is something someone could do. They could buy one of these devices, measure the power (which wouldn't actually be that hard to do), then submit a patch to adjust all the numbers. ;-) -Doug
