linux-kernel - [RFC PATCH 12/16 v3] Bias select wakee than waker in WAKE

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Message-Id: <1401431772-14320-13-git-send-email-yuyang.du@intel.com>
Date:	Fri, 30 May 2014 14:36:08 +0800
From:	Yuyang Du <yuyang.du@...el.com>
To:	mingo@...hat.com, peterz@...radead.org, rafael.j.wysocki@...el.com,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Cc:	arjan.van.de.ven@...el.com, len.brown@...el.com,
	alan.cox@...el.com, mark.gross@...el.com, pjt@...gle.com,
	bsegall@...gle.com, morten.rasmussen@....com,
	vincent.guittot@...aro.org, rajeev.d.muralidhar@...el.com,
	vishwesh.m.rudramuni@...el.com, nicole.chalhoub@...el.com,
	ajaya.durg@...el.com, harinarayanan.seshadri@...el.com,
	jacob.jun.pan@...ux.intel.com, fengguang.wu@...el.com,
	yuyang.du@...el.com
Subject: [RFC PATCH 12/16 v3] Bias select wakee than waker in WAKE_AFFINE

In WAKE_AFFINE, we do not simply select idle, but bias wakee than waker
if the cc of the wakee and waker (in this order) is capable of handling
the wakee task

Signed-off-by: Yuyang Du <yuyang.du@...el.com>
---
 kernel/sched/fair.c |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 0c188df..d40ec9e 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4370,7 +4370,18 @@ static int select_idle_sibling(struct task_struct *p, int target)
 	struct sched_group *sg;
 	int i = task_cpu(p);
 
-	if (idle_cpu(target))
+	/*
+	 * we do not select idle, if the cc of the wakee and
+	 * waker (in this order) is capable of handling the wakee task
+	 */
+	if (sysctl_sched_cc_wakeup_threshold) {
+		if (idle_cpu(i) || cpu_cc_capable(i))
+			return i;
+
+		if (i != target && (idle_cpu(target) || cpu_cc_capable(target)))
+			return target;
+	}
+	else if (idle_cpu(target))
 		return target;
 
 	/*
-- 
1.7.9.5

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