Commit-ID: a030d7381d8b3adabde724e3077bb6cb32d1b3ee
Gitweb: http://git.kernel.org/tip/a030d7381d8b3adabde724e3077bb6cb32d1b3ee
Author: Viresh Kumar <viresh.ku...@linaro.org>
AuthorDate: Wed, 24 May 2017 10:59:52 +0530
Committer: Ingo Molnar <mi...@kernel.org>
CommitDate: Thu, 10 Aug 2017 12:18:09 +0200
sched/fair: Call cpufreq update util handlers less frequently on UP
For SMP systems, update_load_avg() calls the cpufreq update util
handlers only for the top level cfs_rq (i.e. rq->cfs).
But that is not the case for UP systems. update_load_avg() calls util
handler for any cfs_rq for which it is called. This would result in way
too many calls from the scheduler to the cpufreq governors when
CONFIG_FAIR_GROUP_SCHED is enabled.
Reduce the frequency of these calls by copying the behavior from the SMP
case, i.e. Only call util handlers for the top level cfs_rq.
Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Vincent Guittot <vincent.guit...@linaro.org>
Cc: linaro-ker...@lists.linaro.org
Fixes: 536bd00cdbb7 ("sched/fair: Fix !CONFIG_SMP kernel cpufreq governor
breakage")
Link:
http://lkml.kernel.org/r/6abf69a2107525885b616a2c1ec03d9c0946171c.1495603536.git.viresh.ku...@linaro.org
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
kernel/sched/fair.c | 48 ++++++++++++++++++++++++------------------------
1 file changed, 24 insertions(+), 24 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c95880e..139abf2 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2790,6 +2790,29 @@ static inline void update_cfs_shares(struct sched_entity
*se)
}
#endif /* CONFIG_FAIR_GROUP_SCHED */
+static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq)
+{
+ if (&this_rq()->cfs == cfs_rq) {
+ /*
+ * There are a few boundary cases this might miss but it should
+ * get called often enough that that should (hopefully) not be
+ * a real problem -- added to that it only calls on the local
+ * CPU, so if we enqueue remotely we'll miss an update, but
+ * the next tick/schedule should update.
+ *
+ * It will not get called when we go idle, because the idle
+ * thread is a different class (!fair), nor will the utilization
+ * number include things like RT tasks.
+ *
+ * As is, the util number is not freq-invariant (we'd have to
+ * implement arch_scale_freq_capacity() for that).
+ *
+ * See cpu_util().
+ */
+ cpufreq_update_util(rq_of(cfs_rq), 0);
+ }
+}
+
#ifdef CONFIG_SMP
/*
* Approximate:
@@ -3276,29 +3299,6 @@ static inline void set_tg_cfs_propagate(struct cfs_rq
*cfs_rq) {}
#endif /* CONFIG_FAIR_GROUP_SCHED */
-static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq)
-{
- if (&this_rq()->cfs == cfs_rq) {
- /*
- * There are a few boundary cases this might miss but it should
- * get called often enough that that should (hopefully) not be
- * a real problem -- added to that it only calls on the local
- * CPU, so if we enqueue remotely we'll miss an update, but
- * the next tick/schedule should update.
- *
- * It will not get called when we go idle, because the idle
- * thread is a different class (!fair), nor will the utilization
- * number include things like RT tasks.
- *
- * As is, the util number is not freq-invariant (we'd have to
- * implement arch_scale_freq_capacity() for that).
- *
- * See cpu_util().
- */
- cpufreq_update_util(rq_of(cfs_rq), 0);
- }
-}
-
/*
* Unsigned subtract and clamp on underflow.
*
@@ -3544,7 +3544,7 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq,
bool update_freq)
static inline void update_load_avg(struct sched_entity *se, int not_used1)
{
- cpufreq_update_util(rq_of(cfs_rq_of(se)), 0);
+ cfs_rq_util_change(cfs_rq_of(se));
}
static inline void
