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[1/2] sched: cpufreq: ignore SMT when determining max cpu capacity

Message ID 1472236848-17038-2-git-send-email-smuckle@linaro.org
State Accepted
Commit 8314bc83f6a33958a033955e9bdc48e8dd4d5fb0
Headers show

Commit Message

Steve Muckle Aug. 26, 2016, 6:40 p.m. UTC
PELT does not consider SMT when scaling its utilization values via
arch_scale_cpu_capacity(). The value in rq->cpu_capacity_orig does
take SMT into consideration though and therefore may be smaller than
the utilization reported by PELT.

On an Intel i7-3630QM for example rq->cpu_capacity_orig is 589 but
util_avg scales up to 1024. This means that a 50% utilized CPU will show
up in schedutil as ~86% busy.

Fix this by using the same CPU scaling value in schedutil as that which
is used by PELT.

Signed-off-by: Steve Muckle <smuckle@linaro.org>

---
 kernel/sched/cpufreq_schedutil.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

-- 
2.7.3
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Patch

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 60d985f4dc47..cb8a77b1ef1b 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -147,7 +147,9 @@  static unsigned int get_next_freq(struct sugov_cpu *sg_cpu, unsigned long util,
 static void sugov_get_util(unsigned long *util, unsigned long *max)
 {
 	struct rq *rq = this_rq();
-	unsigned long cfs_max = rq->cpu_capacity_orig;
+	unsigned long cfs_max;
+
+	cfs_max = arch_scale_cpu_capacity(NULL, smp_processor_id());
 
 	*util = min(rq->cfs.avg.util_avg, cfs_max);
 	*max = cfs_max;