linux-kernel - [PATCH RFC v2 2/4] sched: sched feature for cpu frequency selection

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Date:	Mon, 11 May 2015 19:13:13 -0700
From:	Michael Turquette <mturquette@...aro.org>
To:	peterz@...radead.org, mingo@...nel.org
Cc:	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	preeti@...ux.vnet.ibm.com, Morten.Rasmussen@....com,
	riel@...hat.com, efault@....de, nicolas.pitre@...aro.org,
	daniel.lezcano@...aro.org, dietmar.eggemann@....com,
	vincent.guittot@...aro.org, amit.kucheria@...aro.org,
	juri.lelli@....com, rjw@...ysocki.net, viresh.kumar@...aro.org,
	ashwin.chaugule@...aro.org, alex.shi@...aro.org,
	abelvesa@...il.com, Michael Turquette <mturquette@...aro.org>
Subject: [PATCH RFC v2 2/4] sched: sched feature for cpu frequency selection

This patch introduces the SCHED_ENERGY_FREQ sched feature, which is
implemented using jump labels when SCHED_DEBUG is defined. It is
statically set to false when SCHED_DEBUG is not defined and thus
disabled by default.

Signed-off-by: Michael Turquette <mturquette@...aro.org>
---
Changes in v2:
	none

 kernel/sched/fair.c     | 5 +++++
 kernel/sched/features.h | 6 ++++++
 2 files changed, 11 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 46855d0..75aec8d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4207,6 +4207,11 @@ static inline void hrtick_update(struct rq *rq)
 }
 #endif
 
+static inline bool sched_energy_freq(void)
+{
+	return sched_feat(SCHED_ENERGY_FREQ);
+}
+
 /*
  * The enqueue_task method is called before nr_running is
  * increased. Here we update the fair scheduling stats and
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index 91e33cd..77381cf 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -96,3 +96,9 @@ SCHED_FEAT(NUMA_FAVOUR_HIGHER, true)
  */
 SCHED_FEAT(NUMA_RESIST_LOWER, false)
 #endif
+
+/*
+ * Scheduler-driven CPU frequency selection aimed to save energy based on
+ * load tracking
+ */
+SCHED_FEAT(SCHED_ENERGY_FREQ, false)
-- 
1.9.1

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