From 43e3089561cba9b1ca94c22768d59b54557399cf Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Tue, 1 Sep 2009 10:34:35 +0200
Subject: [PATCH] --- yaml --- r: 158367 b: refs/heads/master c:
 a52bfd73589eaf88d9c95ad2c1de0b38a6b27972 h: refs/heads/master i:   158365:
 19a29a5424d17ce3123b2981cc89770bf7abd3fb   158363:
 80438ca781c36697e5860fd3a237f7810099a4f5   158359:
 56a37c3475dae98ff7a2808d29b9a8f0b3b411d6   158351:
 8d5e9336bd7cba73552b498dd62ed38945592c3b   158335:
 5d36b2e7e304e4eecc4e98f628298ccc0ce769ed v: v3

---
 [refs]                         | 2 +-
 trunk/include/linux/sched.h    | 1 +
 trunk/include/linux/topology.h | 1 +
 trunk/kernel/sched.c           | 8 +++++++-
 4 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index b8840777da51..47cb3abb0934 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: cc9fba7d7672fa3ed58d9d9ecb6c45b1351c29a6
+refs/heads/master: a52bfd73589eaf88d9c95ad2c1de0b38a6b27972
diff --git a/trunk/include/linux/sched.h b/trunk/include/linux/sched.h
index 651dded25720..9c81c921acb3 100644
--- a/trunk/include/linux/sched.h
+++ b/trunk/include/linux/sched.h
@@ -921,6 +921,7 @@ struct sched_domain {
 	unsigned int newidle_idx;
 	unsigned int wake_idx;
 	unsigned int forkexec_idx;
+	unsigned int smt_gain;
 	int flags;			/* See SD_* */
 	enum sched_domain_level level;
 
diff --git a/trunk/include/linux/topology.h b/trunk/include/linux/topology.h
index 7402c1a27c4f..6203ae5067ce 100644
--- a/trunk/include/linux/topology.h
+++ b/trunk/include/linux/topology.h
@@ -99,6 +99,7 @@ int arch_update_cpu_topology(void);
 				| SD_SHARE_CPUPOWER,	\
 	.last_balance		= jiffies,		\
 	.balance_interval	= 1,			\
+	.smt_gain		= 1178,	/* 15% */	\
 }
 #endif
 #endif /* CONFIG_SCHED_SMT */
diff --git a/trunk/kernel/sched.c b/trunk/kernel/sched.c
index ecb4a47d4214..55112261027b 100644
--- a/trunk/kernel/sched.c
+++ b/trunk/kernel/sched.c
@@ -8523,9 +8523,15 @@ static void init_sched_groups_power(int cpu, struct sched_domain *sd)
 		weight = cpumask_weight(sched_domain_span(sd));
 		/*
 		 * SMT siblings share the power of a single core.
+		 * Usually multiple threads get a better yield out of
+		 * that one core than a single thread would have,
+		 * reflect that in sd->smt_gain.
 		 */
-		if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1)
+		if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
+			power *= sd->smt_gain;
 			power /= weight;
+			power >>= SCHED_LOAD_SHIFT;
+		}
 		sg_inc_cpu_power(sd->groups, power);
 		return;
 	}