Messages in this thread | | | Date | Tue, 5 Dec 2017 17:40:28 +0100 | From | Juri Lelli <> | Subject | Re: [RFC PATCH v2 1/8] sched/cpufreq_schedutil: make use of DEADLINE utilization signal |
| |
On 05/12/17 16:34, Patrick Bellasi wrote: > On 05-Dec 16:24, Juri Lelli wrote: > > On 05/12/17 15:09, Patrick Bellasi wrote: > > > > + /* > > > > + * Ideally we would like to set util_dl as min/guaranteed freq and > > > > + * util_cfs + util_dl as requested freq. However, cpufreq is not yet > > > > + * ready for such an interface. So, we only do the latter for now. > > > > + */ > > > > > > Maybe I don't completely get the above comment, but to me it is not > > > really required. > > > > > > When you say that "util_dl" should be set to a min/guaranteed freq > > > are you not actually talking about a DL implementation detail? > > > > > > From the cpufreq standpoint instead, we should always set a capacity > > > which can accommodate util_dl + util_cfs. > > > > It's more for platforms which supports such combination of values for > > frequency requests (CPPC like, AFAIU). The idea being that util_dl is > > what the system has to always guarantee, but it could go up to the sum > > if feasible. > > I see, you mean for systems where you can specify both values at the > same time, i.e. > - please give me util_dl... > - ... but if you have more beer, I would like util_dl + util_cfs > > However, I'm not an expert, on those systems can we really set a > minimum guaranteed performance level?
This is my current understanding. Never played with such platforms myself. :)
Best,
- Juri
| |