Prepare em_pd_get_efficient_state() for the upcoming changes and
make it possible to re-use. Return an index for the best performance
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.
Signed-off-by: Lukasz Luba <[email protected]>
---
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)
--
2.25.1
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 <[email protected]>
> ---
> 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)
On 5/30/23 12:06, Dietmar Eggemann wrote:
> 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?
The function will no longer get a pointer to 'struct em_perf_domain'
but instead to 'struct em_perf_state'. It would also require to
get the number of states from 'pd->nr_perf_states'.
This is preparation for handling 2 tables:
modifiable (a) and default (b).
Then it also returns and ID not the pointer to state.
It all makes it more generic and ready for those 2 tables.
>
>> 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.
I will add that description as 'why' in the header. I wanted to
avoid mentioning in the patch description something which
is coming in the next patch.