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Commit 182276b6 authored by Syed Rameez Mustafa's avatar Syed Rameez Mustafa Committed by Joonwoo Park
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sched: update placement logic to prefer C-state and busier CPUs 



Update the wakeup placement logic when need_idle is not set. Break
ties in power with C-state. If C-state is the same break ties with
prev_cpu. Finally go for the most loaded CPU.

CRs-fixed: 1006303
Change-Id: Iafa98a909ed464af33f4fe3345bbfc8e77dee963
Signed-off-by: default avatarSyed Rameez Mustafa <rameezmustafa@codeaurora.org>
[joonwoop@codeaurora.org: fixed bug where assigns best_cpu_cstate with
 uninitialized cpu_cstate.]
Signed-off-by: default avatarJoonwoo Park <joonwoop@codeaurora.org>
parent a57aa933

kernel/sched/fair.c

+31 −6
Original line number Diff line number Diff line
@@ -2915,7 +2915,7 @@ struct cluster_cpu_stats { 
	int best_capacity_cpu, best_cpu, best_sibling_cpu;

	int min_cost, best_sibling_cpu_cost;

	int best_cpu_cstate;

	u64 min_load, best_sibling_cpu_load;

	u64 min_load, max_load, best_sibling_cpu_load;

	s64 highest_spare_capacity;

};
@@ -3170,10 +3170,11 @@ static void update_cluster_stats(int cpu, struct cluster_cpu_stats *stats, 
		}

	}



	cpu_cstate = cpu_rq(cpu)->cstate;



	if (env->need_idle) {

		stats->min_cost = cpu_cost;

		if (idle_cpu(cpu)) {

			cpu_cstate = cpu_rq(cpu)->cstate;

			if (cpu_cstate < stats->best_cpu_cstate ||

				(cpu_cstate == stats->best_cpu_cstate &&

							cpu == prev_cpu)) {
@@ -3192,11 +3193,34 @@ static void update_cluster_stats(int cpu, struct cluster_cpu_stats *stats, 
		return;

	}



	if ((cpu_cost < stats->min_cost) ||

	    ((stats->best_cpu != prev_cpu && stats->min_load > env->cpu_load) ||

	     cpu == prev_cpu)) {

	if (cpu_cost < stats->min_cost)  {

		stats->min_cost = cpu_cost;

		stats->min_load = env->cpu_load;

		stats->best_cpu_cstate = cpu_cstate;

		stats->max_load = env->cpu_load;

		stats->best_cpu = cpu;

		return;

	}



	/* CPU cost is the same. Start breaking the tie by C-state */



	if (cpu_cstate > stats->best_cpu_cstate)

		return;



	if (cpu_cstate < stats->best_cpu_cstate) {

		stats->best_cpu_cstate = cpu_cstate;

		stats->max_load = env->cpu_load;

		stats->best_cpu = cpu;

		return;

	}



	/* C-state is the same. Use prev CPU to break the tie */

	if (cpu == prev_cpu) {

		stats->best_cpu = cpu;

		return;

	}



	if (stats->best_cpu != prev_cpu && env->cpu_load > stats->max_load) {

		stats->max_load = env->cpu_load;

		stats->best_cpu = cpu;

	}

}
@@ -3240,6 +3264,7 @@ static inline void init_cluster_cpu_stats(struct cluster_cpu_stats *stats) 
	stats->best_capacity_cpu = stats->best_sibling_cpu  = -1;

	stats->min_cost = stats->best_sibling_cpu_cost = INT_MAX;

	stats->min_load	= stats->best_sibling_cpu_load = ULLONG_MAX;

	stats->max_load = 0;

	stats->highest_spare_capacity = 0;

	stats->least_loaded_cpu = -1;

	stats->best_cpu_cstate = INT_MAX;