linux-kernel - [PATCH 12/10] sched, fair: Fix group power

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Date:	Wed, 28 Aug 2013 13:14:45 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Ingo Molnar <mingo@...nel.org>,
	Joonsoo Kim <iamjoonsoo.kim@....com>
Cc:	linux-kernel@...r.kernel.org, Mike Galbraith <efault@....de>,
	Paul Turner <pjt@...gle.com>, Alex Shi <alex.shi@...el.com>,
	Preeti U Murthy <preeti@...ux.vnet.ibm.com>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Morten Rasmussen <morten.rasmussen@....com>,
	Namhyung Kim <namhyung@...nel.org>,
	Lei Wen <leiwen@...vell.com>, Joonsoo Kim <js1304@...il.com>,
	Rik van Riel <riel@...riel.com>,
	Michael Neuling <mikey@...ling.org>
Subject: [PATCH 12/10] sched, fair: Fix group power_orig computation


Subject: sched, fair: Fix group power_orig computation
From: Peter Zijlstra <peterz@...radead.org>
Date: Wed Aug 28 11:44:39 CEST 2013

When looking at the code I noticed we don't actually compute
sgp->power_orig correctly for groups, fix that.

Currently the only consumer of that value is fix_small_capacity()
which is only used on POWER7+ and that code excludes this case by
being limited to SD_SHARE_CPUPOWER which is only ever set on the SMT
domain which must be the lowest domain and this has singleton groups.

So nothing should be affected by this change.

Cc: Michael Neuling <mikey@...ling.org>
Signed-off-by: Peter Zijlstra <peterz@...radead.org>
---
 kernel/sched/fair.c |   40 ++++++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 14 deletions(-)

--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4448,7 +4448,7 @@ void update_group_power(struct sched_dom
 {
 	struct sched_domain *child = sd->child;
 	struct sched_group *group, *sdg = sd->groups;
-	unsigned long power;
+	unsigned long power, power_orig;
 	unsigned long interval;
 
 	interval = msecs_to_jiffies(sd->balance_interval);
@@ -4460,7 +4460,7 @@ void update_group_power(struct sched_dom
 		return;
 	}
 
-	power = 0;
+	power_orig = power = 0;
 
 	if (child->flags & SD_OVERLAP) {
 		/*
@@ -4468,8 +4468,12 @@ void update_group_power(struct sched_dom
 		 * span the current group.
 		 */
 
-		for_each_cpu(cpu, sched_group_cpus(sdg))
-			power += power_of(cpu);
+		for_each_cpu(cpu, sched_group_cpus(sdg)) {
+			struct sched_group *sg = cpu_rq(cpu)->sd->groups;
+
+			power_orig += sg->sgp->power_orig;
+			power += sg->sgp->power;
+		}
 	} else  {
 		/*
 		 * !SD_OVERLAP domains can assume that child groups
@@ -4478,12 +4482,14 @@ void update_group_power(struct sched_dom
 
 		group = child->groups;
 		do {
+			power_orig += group->sgp->power_orig;
 			power += group->sgp->power;
 			group = group->next;
 		} while (group != child->groups);
 	}
 
-	sdg->sgp->power_orig = sdg->sgp->power = power;
+	sdg->sgp->power_orig = power_orig;
+	sdg->sgp->power = power;
 }
 
 /*
--
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