linux-kernel - [RFC PATCH V2 19/19] sched: don't do power balance on share cpu power domain

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Date:	Mon, 11 Aug 2014 17:20:20 +0530
From:	Preeti U Murthy <preeti@...ux.vnet.ibm.com>
To:	alex.shi@...el.com, vincent.guittot@...aro.org,
	peterz@...radead.org, pjt@...gle.com, efault@....de,
	rjw@...ysocki.net, morten.rasmussen@....com,
	svaidy@...ux.vnet.ibm.com, arjan@...ux.intel.com, mingo@...nel.org
Cc:	nicolas.pitre@...aro.org, len.brown@...el.com, yuyang.du@...el.com,
	linaro-kernel@...ts.linaro.org, daniel.lezcano@...aro.org,
	corbet@....net, catalin.marinas@....com, markgross@...gnar.org,
	sundar.iyer@...el.com, linux-kernel@...r.kernel.org,
	dietmar.eggemann@....com, Lorenzo.Pieralisi@....com,
	mike.turquette@...aro.org, akpm@...ux-foundation.org,
	paulmck@...ux.vnet.ibm.com, tglx@...utronix.de
Subject: [RFC PATCH V2 19/19] sched: don't do power balance on share cpu
 power domain

From: Alex Shi <alex.shi@...el.com>

Packing tasks among such domain can't save power, just performance
losing. So no power balance on them.

Signed-off-by: Alex Shi <alex.shi@...el.com>
[Added CONFIG_SCHED_POWER switch to enable this patch]
Signed-off-by: Preeti U Murthy <preeti@...ux.vnet.ibm.com>
---

 kernel/sched/fair.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c49ee6c..adda9cf 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4744,7 +4744,7 @@ static int get_cpu_for_power_policy(struct sched_domain *sd, int cpu,
 
 	policy = get_sd_sched_balance_policy(sd, cpu, p, sds);
 	if (policy != SCHED_POLICY_PERFORMANCE && sds->group_leader) {
-		if (wakeup)
+		if (wakeup && !(sd->flags & SD_SHARE_CPUCAPACITY))
 			new_cpu = find_leader_cpu(sds->group_leader,
 							p, cpu, policy);
 		/* for fork balancing and a little busy task */
@@ -5882,8 +5882,9 @@ static inline void init_sd_lb_stats(struct sd_lb_stats *sds)
 static inline void init_sd_lb_power_stats(struct lb_env *env,
 						struct sd_lb_stats *sds)
 {
-	if (sched_balance_policy == SCHED_POLICY_PERFORMANCE ||
-				env->idle == CPU_NOT_IDLE) {
+	if (sched_balance_policy == SCHED_POLICY_PERFORMANCE
+			|| env->sd->flags & SD_SHARE_CPUCAPACITY
+			|| env->idle == CPU_NOT_IDLE) {
 		env->flags &= ~LBF_POWER_BAL;
 		env->flags |= LBF_PERF_BAL;
 		return;

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