diff mbox series

[v4,04/18] PM: EM: Refactor em_pd_get_efficient_state() to be more flexible

Message ID 20230925081139.1305766-5-lukasz.luba@arm.com
State New
Headers
Series Introduce runtime modifiable Energy Model |

Commit Message

Lukasz Luba Sept. 25, 2023, 8:11 a.m. UTC 
  The Energy Model (EM) is going to support runtime modification. There
are going to be 2 EM tables which store information. This patch aims
to prepare the code to be generic and use one of the tables. The function
will no longer get a pointer to 'struct em_perf_domain' (the EM) but
instead a pointer to 'struct em_perf_state' (which is one of the EM's
tables).

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 for a given EM table. 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 <lukasz.luba@arm.com>
---
 include/linux/energy_model.h | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

Comments

Daniel Lezcano Oct. 23, 2023, 5:39 p.m. UTC | #1 
On 25/09/2023 10:11, Lukasz Luba wrote:
> The Energy Model (EM) is going to support runtime modification. There
> are going to be 2 EM tables which store information. This patch aims
> to prepare the code to be generic and use one of the tables. The function
> will no longer get a pointer to 'struct em_perf_domain' (the EM) but
> instead a pointer to 'struct em_perf_state' (which is one of the EM's
> tables).
> 
> 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 for a given EM table. 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 <lukasz.luba@arm.com>
> ---

[ ... ]

> @@ -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);

nitpicking but s/i/state/

Other than that:

Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>


> +	ps = &pd->table[i];
>   
>   	/*
>   	 * The capacity of a CPU in the domain at the performance state (ps)
Lukasz Luba Oct. 24, 2023, 8:09 a.m. UTC | #2 
On 10/23/23 18:39, Daniel Lezcano wrote:
> On 25/09/2023 10:11, Lukasz Luba wrote:
>> The Energy Model (EM) is going to support runtime modification. There
>> are going to be 2 EM tables which store information. This patch aims
>> to prepare the code to be generic and use one of the tables. The function
>> will no longer get a pointer to 'struct em_perf_domain' (the EM) but
>> instead a pointer to 'struct em_perf_state' (which is one of the EM's
>> tables).
>>
>> 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 for a given EM table. 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 <lukasz.luba@arm.com>
>> ---
> 
> [ ... ]
> 
>> @@ -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);
> 
> nitpicking but s/i/state/

Here it makes sense, I'll try to use 'state', but if that could be a bit
odd in later patches code, where I have:

ps = &runtime_table->state[i];

than:

'->state[state]'

won't fly. Although, let me check, because I'm going to drop the
2 tables design so some fields might get different names.

> 
> Other than that:
> 
> Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Thanks!

> 
> 
>> +    ps = &pd->table[i];
>>       /*
>>        * The capacity of a CPU in the domain at the performance state 
>> (ps)
>
diff mbox series

Patch

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)