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Commit e1856dad authored by Pavankumar Kondeti's avatar Pavankumar Kondeti
Browse files

sched/fair: Add provision to control the spreading on SMP 



Spreading the tasks across CPUs in different groups/clusters
may hurt power on some SMP systems. Start spreading the tasks
only if all the CPUs in the primary group/cluster are utilized
above sched_smp_overlap_capacity threshold.

When placement boost is active, the task is placed on the
least loaded CPU across all groups/clusters.

Change-Id: I5da67ed9230f651921bd901cbcc4e0cc55064155
Signed-off-by: default avatarPavankumar Kondeti <pkondeti@codeaurora.org>
parent f07ab013

kernel/sched/fair.c

+32 −1
Original line number Diff line number Diff line
@@ -6833,8 +6833,11 @@ static inline bool skip_sg(struct task_struct *p, struct sched_group *sg, 
static int start_cpu(bool boosted)

{

	struct root_domain *rd = cpu_rq(smp_processor_id())->rd;

	int start_cpu;



	return boosted ? rd->max_cap_orig_cpu : rd->min_cap_orig_cpu;

	start_cpu = boosted ? rd->max_cap_orig_cpu : rd->min_cap_orig_cpu;



	return walt_start_cpu(start_cpu);

}



static inline int find_best_target(struct task_struct *p, int *backup_cpu,
@@ -7119,6 +7122,34 @@ static inline int find_best_target(struct task_struct *p, int *backup_cpu, 
			goto retry;

		}



		if (!sysctl_sched_is_big_little && !prefer_idle) {



			/*

			 * If we find an idle CPU in the primary cluster,

			 * stop the search. We select this idle CPU or

			 * the active CPU (if there is one), whichever

			 * saves the energy.

			 */

			if (best_idle_cpu != -1)

				break;



			if (fbt_env->placement_boost) {

				target_capacity = ULONG_MAX;

				continue;

			}



			/*

			 * If we found an active CPU and its utilization

			 * is below the minimum packing threshold (overlap),

			 * no need to search further. Otherwise reset

			 * the target_capacity and continue the search.

			 */

			if (target_cpu != -1 && target_util <

					sched_smp_overlap_capacity)

				break;



			target_capacity = ULONG_MAX;

		}

	} while (sg = sg->next, sg != sd->groups);



	if (best_idle_cpu != -1 && !is_packing_eligible(p, target_cpu, fbt_env,