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Commit fa709963 authored by Pavankumar Kondeti's avatar Pavankumar Kondeti
Browse files

sched: don't assume higher capacity means higher power in lb 



The load balancer restrictions are in place to control the tasks
migration from the lower capacity cluster to higher capacity
cluster to save power. The assumption here is that higher capacity
cluster will have higher power cost which may not be necessarily
true for all platforms. Use power cost based checks instead of
capacity based checks while applying the inter cluster migration
restrictions.

Change-Id: Id9519eb8f7b183a2e9fca87a23cf95e951aa4005
Signed-off-by: default avatarPavankumar Kondeti <pkondeti@codeaurora.org>
parent 9d219776

kernel/sched/core.c

+7 −0
Original line number Diff line number Diff line
@@ -1311,6 +1311,8 @@ DECLARE_BITMAP(all_cluster_ids, NR_CPUS); 
struct sched_cluster *sched_cluster[NR_CPUS];

int num_clusters;



unsigned int max_power_cost = 1;



static struct sched_cluster init_cluster = {

	.list			=	LIST_HEAD_INIT(init_cluster.list),

	.id			=	0,
@@ -1414,6 +1416,7 @@ static void sort_clusters(void) 
{

	struct sched_cluster *cluster;

	struct list_head new_head;

	unsigned int tmp_max = 1;



	INIT_LIST_HEAD(&new_head);
@@ -1422,7 +1425,11 @@ static void sort_clusters(void) 
							       max_task_load());

		cluster->min_power_cost = power_cost(cluster_first_cpu(cluster),

							       0);



		if (cluster->max_power_cost > tmp_max)

			tmp_max = cluster->max_power_cost;

	}

	max_power_cost = tmp_max;



	move_list(&new_head, &cluster_head, true);

kernel/sched/fair.c

+2 −8
Original line number Diff line number Diff line
@@ -7933,9 +7933,7 @@ bail_inter_cluster_balance(struct lb_env *env, struct sd_lb_stats *sds) 
	local_pwr_cost = cpu_max_power_cost(local_cpu);

	busiest_pwr_cost = cpu_max_power_cost(busiest_cpu);



	if (local_capacity < busiest_capacity ||

			(local_capacity == busiest_capacity &&

			local_pwr_cost <= busiest_pwr_cost))

	if (local_pwr_cost <= busiest_pwr_cost)

		return 0;



	if (local_capacity > busiest_capacity &&
@@ -9611,9 +9609,6 @@ static inline int find_new_hmp_ilb(int type) 
		for_each_cpu_and(ilb, nohz.idle_cpus_mask,

						sched_domain_span(sd)) {

			if (idle_cpu(ilb) && (type != NOHZ_KICK_RESTRICT ||

					(hmp_capable() &&

					 cpu_max_possible_capacity(ilb) <=

					cpu_max_possible_capacity(call_cpu)) ||

					cpu_max_power_cost(ilb) <=

					cpu_max_power_cost(call_cpu))) {

				rcu_read_unlock();
@@ -9930,8 +9925,7 @@ static inline int _nohz_kick_needed_hmp(struct rq *rq, int cpu, int *type) 
	if (!sysctl_sched_restrict_cluster_spill || sched_boost())

		return 1;



	if (hmp_capable() && cpu_max_possible_capacity(cpu) ==

			max_possible_capacity)

	if (cpu_max_power_cost(cpu) == max_power_cost)

		return 1;



	rcu_read_lock();

kernel/sched/sched.h

+1 −0
Original line number Diff line number Diff line
@@ -964,6 +964,7 @@ extern unsigned int min_capacity; 
extern unsigned int max_load_scale_factor;

extern unsigned int max_possible_capacity;

extern unsigned int min_max_possible_capacity;

extern unsigned int max_power_cost;

extern unsigned int sched_upmigrate;

extern unsigned int sched_downmigrate;

extern unsigned int sched_init_task_load_pelt;