Messages in this thread | | | Date | Thu, 21 Sep 2023 11:12:22 +0100 | From | Ionela Voinescu <> | Subject | Re: [PATCH 4/4] energy_model: use a fixed reference frequency |
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On Friday 01 Sep 2023 at 15:03:12 (+0200), Vincent Guittot wrote: > The last item of a performance domain is not always the performance point > that has been used to compute CPU's capacity. This can lead to different > target frequency compared with other part of the system like schedutil and > would result in wrong energy estimation. > > a new arch_scale_freq_ref() is available to return a fixed and coherent > frequency reference that can be used when computing the CPU's frequency > for an level of utilization. Use this function when available or fallback > to the last performance domain item otherwise. > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> > --- > include/linux/energy_model.h | 20 +++++++++++++++++--- > 1 file changed, 17 insertions(+), 3 deletions(-) > > diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h > index b9caa01dfac4..7ee07be6928e 100644 > --- a/include/linux/energy_model.h > +++ b/include/linux/energy_model.h > @@ -204,6 +204,20 @@ struct em_perf_state *em_pd_get_efficient_state(struct em_perf_domain *pd, > return ps; > } > > +#ifdef arch_scale_freq_ref > +static __always_inline > +unsigned long arch_scale_freq_ref_em(int cpu, struct em_perf_domain *pd)
The comments in patch 3/4 should be considered for this function and its use as well.
Thanks, Ionela.
> +{ > + return arch_scale_freq_ref(cpu); > +} > +#else > +static __always_inline > +unsigned long arch_scale_freq_ref_em(int cpu, struct em_perf_domain *pd) > +{ > + return pd->table[pd->nr_perf_states - 1].frequency; > +} > +#endif > + > /** > * em_cpu_energy() - Estimates the energy consumed by the CPUs of a > * performance domain > @@ -224,7 +238,7 @@ static inline unsigned long em_cpu_energy(struct em_perf_domain *pd, > unsigned long max_util, unsigned long sum_util, > unsigned long allowed_cpu_cap) > { > - unsigned long freq, scale_cpu; > + unsigned long freq, ref_freq, scale_cpu; > struct em_perf_state *ps; > int cpu; > > @@ -241,11 +255,11 @@ static inline unsigned long em_cpu_energy(struct em_perf_domain *pd, > */ > cpu = cpumask_first(to_cpumask(pd->cpus)); > scale_cpu = arch_scale_cpu_capacity(cpu); > - ps = &pd->table[pd->nr_perf_states - 1]; > + ref_freq = arch_scale_freq_ref_em(cpu, pd); > > max_util = map_util_perf(max_util); > max_util = min(max_util, allowed_cpu_cap); > - freq = map_util_freq(max_util, ps->frequency, scale_cpu); > + freq = map_util_freq(max_util, ref_freq, scale_cpu); > > /* > * Find the lowest performance state of the Energy Model above the > -- > 2.34.1 > >
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