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From:   Vincent Guittot <vincent.guittot@linaro.org>
To:     linux-kernel@vger.kernel.org, mingo@redhat.com,
        peterz@infradead.org
Cc:     pauld@redhat.com, valentin.schneider@arm.com,
        srikar@linux.vnet.ibm.com, quentin.perret@arm.com,
        dietmar.eggemann@arm.com, Morten.Rasmussen@arm.com,
        hdanton@sina.com, Vincent Guittot <vincent.guittot@linaro.org>
Subject: [PATCH v3 09/10] sched/fair: use load instead of runnable load in wakeup path
Date:   Thu, 19 Sep 2019 09:33:40 +0200
Message-Id: <1568878421-12301-10-git-send-email-vincent.guittot@linaro.org>
In-Reply-To: <1568878421-12301-1-git-send-email-vincent.guittot@linaro.org>
References: <1568878421-12301-1-git-send-email-vincent.guittot@linaro.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

runnable load has been introduced to take into account the case where
blocked load biases the wake up path which may end to select an overloaded
CPU with a large number of runnable tasks instead of an underutilized
CPU with a huge blocked load.

Tha wake up path now starts to looks for idle CPUs before comparing
runnable load and it's worth aligning the wake up path with the
load_balance.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---
 kernel/sched/fair.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index acca869..39a37ae 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5485,7 +5485,7 @@ wake_affine_weight(struct sched_domain *sd, struct task_struct *p,
 	s64 this_eff_load, prev_eff_load;
 	unsigned long task_load;
 
-	this_eff_load = cpu_runnable_load(cpu_rq(this_cpu));
+	this_eff_load = cpu_load(cpu_rq(this_cpu));
 
 	if (sync) {
 		unsigned long current_load = task_h_load(current);
@@ -5503,7 +5503,7 @@ wake_affine_weight(struct sched_domain *sd, struct task_struct *p,
 		this_eff_load *= 100;
 	this_eff_load *= capacity_of(prev_cpu);
 
-	prev_eff_load = cpu_runnable_load(cpu_rq(prev_cpu));
+	prev_eff_load = cpu_load(cpu_rq(prev_cpu));
 	prev_eff_load -= task_load;
 	if (sched_feat(WA_BIAS))
 		prev_eff_load *= 100 + (sd->imbalance_pct - 100) / 2;
@@ -5591,7 +5591,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p,
 		max_spare_cap = 0;
 
 		for_each_cpu(i, sched_group_span(group)) {
-			load = cpu_runnable_load(cpu_rq(i));
+			load = cpu_load(cpu_rq(i));
 			runnable_load += load;
 
 			avg_load += cfs_rq_load_avg(&cpu_rq(i)->cfs);
@@ -5732,7 +5732,7 @@ find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this
 				continue;
 			}
 
-			load = cpu_runnable_load(cpu_rq(i));
+			load = cpu_load(cpu_rq(i));
 			if (load < min_load) {
 				min_load = load;
 				least_loaded_cpu = i;
-- 
2.7.4