Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5cdeb5f0 authored by Morten Rasmussen's avatar Morten Rasmussen Committed by Dmitry Shmidt
Browse files

ANDROID: sched: Add per-cpu max capacity to sched_group_capacity 



struct sched_group_capacity currently represents the compute capacity
sum of all cpus in the sched_group. Unless it is divided by the
group_weight to get the average capacity per cpu it hides differences in
cpu capacity for mixed capacity systems (e.g. high RT/IRQ utilization or
ARM big.LITTLE). But even the average may not be sufficient if the group
covers cpus of different capacities. Instead, by extending struct
sched_group_capacity to indicate max per-cpu capacity in the group a
suitable group for a given task utilization can easily be found such
that cpus with reduced capacity can be avoided for tasks with high
utilization (not implemented by this patch).

Signed-off-by: default avatarMorten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: default avatarAndres Oportus <andresoportus@google.com>
parent 785367fc

kernel/sched/core.c

+2 −1
Original line number Diff line number Diff line
@@ -5707,7 +5707,7 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, 
		printk(KERN_CONT " %*pbl",

		       cpumask_pr_args(sched_group_cpus(group)));

		if (group->sgc->capacity != SCHED_CAPACITY_SCALE) {

			printk(KERN_CONT " (cpu_capacity = %d)",

			printk(KERN_CONT " (cpu_capacity = %lu)",

				group->sgc->capacity);

		}
@@ -6202,6 +6202,7 @@ build_overlap_sched_groups(struct sched_domain *sd, int cpu) 
		 * die on a /0 trap.

		 */

		sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span);

		sg->sgc->max_capacity = SCHED_CAPACITY_SCALE;



		/*

		 * Make sure the first group of this domain contains the

kernel/sched/fair.c

+12 −5
Original line number Diff line number Diff line
@@ -7291,13 +7291,14 @@ skip_unlock: __attribute__ ((unused)); 


	cpu_rq(cpu)->cpu_capacity = capacity;

	sdg->sgc->capacity = capacity;

	sdg->sgc->max_capacity = capacity;

}



void update_group_capacity(struct sched_domain *sd, int cpu)

{

	struct sched_domain *child = sd->child;

	struct sched_group *group, *sdg = sd->groups;

	unsigned long capacity;

	unsigned long capacity, max_capacity;

	unsigned long interval;



	interval = msecs_to_jiffies(sd->balance_interval);
@@ -7310,6 +7311,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu) 
	}



	capacity = 0;

	max_capacity = 0;



	if (child->flags & SD_OVERLAP) {

		/*
@@ -7334,12 +7336,13 @@ void update_group_capacity(struct sched_domain *sd, int cpu) 
			 */

			if (unlikely(!rq->sd)) {

				capacity += capacity_of(cpu);

				continue;

			}



			} else {

				sgc = rq->sd->groups->sgc;

				capacity += sgc->capacity;

			}



			max_capacity = max(capacity, max_capacity);

		}

	} else  {

		/*

		 * !SD_OVERLAP domains can assume that child groups
@@ -7348,12 +7351,16 @@ void update_group_capacity(struct sched_domain *sd, int cpu) 


		group = child->groups;

		do {

			capacity += group->sgc->capacity;

			struct sched_group_capacity *sgc = group->sgc;



			capacity += sgc->capacity;

			max_capacity = max(sgc->max_capacity, max_capacity);

			group = group->next;

		} while (group != child->groups);

	}



	sdg->sgc->capacity = capacity;

	sdg->sgc->max_capacity = max_capacity;

}



/*

kernel/sched/sched.h

+2 −1
Original line number Diff line number Diff line
@@ -905,7 +905,8 @@ struct sched_group_capacity { 
	 * CPU capacity of this group, SCHED_CAPACITY_SCALE being max capacity

	 * for a single CPU.

	 */

	unsigned int capacity;

	unsigned long capacity;

	unsigned long max_capacity; /* Max per-cpu capacity in group */

	unsigned long next_update;

	int imbalance; /* XXX unrelated to capacity but shared group state */