linux-kernel - [PATCH 4/7] sched/fair: don't include effective load of process in the old cpu load

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Date:   Fri, 14 Jul 2017 13:21:01 +0000
From:   Josef Bacik <josef@...icpanda.com>
To:     mingo@...hat.com, peterz@...radead.org,
        linux-kernel@...r.kernel.org, umgwanakikbuti@...il.com,
        tj@...nel.org, kernel-team@...com
Cc:     Josef Bacik <jbacik@...com>
Subject: [PATCH 4/7] sched/fair: don't include effective load of process in the old cpu load

From: Josef Bacik <jbacik@...com>

We have no idea how long ago the process went to sleep.  It could have just gone
to sleep, in which case we would essentially be counting the load of the process
twice in the previous effective load.  Since the history presumably already
exists in the previous cpu load don't bother adding it's effective load again.

Signed-off-by: Josef Bacik <jbacik@...com>
---
 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d958634..ee8dced 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5689,7 +5689,7 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p,
 		this_eff_load *= this_load +
 			effective_load(tg, this_cpu, weight, weight);
 
-		prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight);
+		prev_eff_load *= load;
 	}
 
 	balanced = this_eff_load <= prev_eff_load;
-- 
2.9.3