Messages in this thread | | | Date | Tue, 30 May 2023 13:06:14 +0200 | Subject | Re: [PATCH v2 03/17] PM: EM: Refactor em_pd_get_efficient_state() to be more flexible | From | Dietmar Eggemann <> |
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On 12/05/2023 11:57, Lukasz Luba wrote: > Prepare em_pd_get_efficient_state() for the upcoming changes and > make it possible to re-use. Return an index for the best performance
Don't get the `possible to re-use`? Did you mean `possible to be re-used`? But then `re-used` for what?
> state. The function arguments that are introduced should allow to > work on different performance state arrays. The caller of > em_pd_get_efficient_state() should be able to use the index either > on the default or the modifiable EM table.
This describes the WHAT but not the WHY.
> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> > --- > include/linux/energy_model.h | 30 +++++++++++++++++------------- > 1 file changed, 17 insertions(+), 13 deletions(-) > > diff --git a/include/linux/energy_model.h b/include/linux/energy_model.h > index b9caa01dfac4..8069f526c9d8 100644 > --- a/include/linux/energy_model.h > +++ b/include/linux/energy_model.h > @@ -175,33 +175,35 @@ void em_dev_unregister_perf_domain(struct device *dev); > > /** > * em_pd_get_efficient_state() - Get an efficient performance state from the EM > - * @pd : Performance domain for which we want an efficient frequency > - * @freq : Frequency to map with the EM > + * @state: List of performance states, in ascending order > + * @nr_perf_states: Number of performance states > + * @freq: Frequency to map with the EM > + * @pd_flags: Performance Domain flags > * > * It is called from the scheduler code quite frequently and as a consequence > * doesn't implement any check. > * > - * Return: An efficient performance state, high enough to meet @freq > + * Return: An efficient performance state id, high enough to meet @freq > * requirement. > */ > -static inline > -struct em_perf_state *em_pd_get_efficient_state(struct em_perf_domain *pd, > - unsigned long freq) > +static inline int > +em_pd_get_efficient_state(struct em_perf_state *table, int nr_perf_states, > + unsigned long freq, unsigned long pd_flags) > { > struct em_perf_state *ps; > int i; > > - for (i = 0; i < pd->nr_perf_states; i++) { > - ps = &pd->table[i]; > + for (i = 0; i < nr_perf_states; i++) { > + ps = &table[i]; > if (ps->frequency >= freq) { > - if (pd->flags & EM_PERF_DOMAIN_SKIP_INEFFICIENCIES && > + if (pd_flags & EM_PERF_DOMAIN_SKIP_INEFFICIENCIES && > ps->flags & EM_PERF_STATE_INEFFICIENT) > continue; > - break; > + return i; > } > } > > - return ps; > + return nr_perf_states - 1; > } > > /** > @@ -226,7 +228,7 @@ static inline unsigned long em_cpu_energy(struct em_perf_domain *pd, > { > unsigned long freq, scale_cpu; > struct em_perf_state *ps; > - int cpu; > + int cpu, i; > > if (!sum_util) > return 0; > @@ -251,7 +253,9 @@ static inline unsigned long em_cpu_energy(struct em_perf_domain *pd, > * Find the lowest performance state of the Energy Model above the > * requested frequency. > */ > - ps = em_pd_get_efficient_state(pd, freq); > + i = em_pd_get_efficient_state(pd->table, pd->nr_perf_states, freq, > + pd->flags); > + ps = &pd->table[i]; > > /* > * The capacity of a CPU in the domain at the performance state (ps)
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