Commit 22ea0284 authored by Lukasz Luba's avatar Lukasz Luba Committed by Rafael J. Wysocki
Browse files

PM: EM: Add em_dev_compute_costs() 



The device drivers can modify EM at runtime by providing a new EM table.
The EM is used by the EAS and the em_perf_state::cost stores
pre-calculated value to avoid overhead. This patch provides the API for
device drivers to calculate the cost values properly (and not duplicate
the same code).

Reviewed-by: default avatarDietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: default avatarDietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: default avatarLukasz Luba <lukasz.luba@arm.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 24e9fb63

include/linux/energy_model.h

+8 −0
Original line number Diff line number Diff line
@@ -170,6 +170,8 @@ int em_dev_register_perf_domain(struct device *dev, unsigned int nr_states, 
void em_dev_unregister_perf_domain(struct device *dev);

struct em_perf_table __rcu *em_table_alloc(struct em_perf_domain *pd);

void em_table_free(struct em_perf_table __rcu *table);

int em_dev_compute_costs(struct device *dev, struct em_perf_state *table,

			 int nr_states);



/**

 * em_pd_get_efficient_state() - Get an efficient performance state from the EM
@@ -379,6 +381,12 @@ struct em_perf_state *em_perf_state_from_pd(struct em_perf_domain *pd) 
{

	return NULL;

}

static inline

int em_dev_compute_costs(struct device *dev, struct em_perf_state *table,

			 int nr_states)

{

	return -EINVAL;

}

#endif



#endif

kernel/power/energy_model.c

+18 −0
Original line number Diff line number Diff line
@@ -276,6 +276,24 @@ static int em_compute_costs(struct device *dev, struct em_perf_state *table, 
	return 0;

}



/**

 * em_dev_compute_costs() - Calculate cost values for new runtime EM table

 * @dev		: Device for which the EM table is to be updated

 * @table	: The new EM table that is going to get the costs calculated

 *

 * Calculate the em_perf_state::cost values for new runtime EM table. The

 * values are used for EAS during task placement. It also calculates and sets

 * the efficiency flag for each performance state. When the function finish

 * successfully the EM table is ready to be updated and used by EAS.

 *

 * Return 0 on success or a proper error in case of failure.

 */

int em_dev_compute_costs(struct device *dev, struct em_perf_state *table,

			 int nr_states)

{

	return em_compute_costs(dev, table, NULL, nr_states, 0);

}



/**

 * em_dev_update_perf_domain() - Update runtime EM table for a device

 * @dev		: Device for which the EM is to be updated