[tip:sched/core] sched/fair: Call cpufreq update util handlers less frequently on UP

[tip-bot for Viresh Kumar]

Commit-ID:  a030d7381d8b3adabde724e3077bb6cb32d1b3ee
Gitweb: http://git.kernel.org/tip/a030d7381d8b3adabde724e3077bb6cb32d1b3ee
Author: Viresh Kumar 
AuthorDate: Wed, 24 May 2017 10:59:52 +0530
Committer:  Ingo Molnar 
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 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Vincent Guittot 
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 
---
 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 (_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 (_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

[tip:sched/core] sched/fair: Call cpufreq update util handlers less frequently on UP

[tip-bot for Viresh Kumar]

Commit-ID:  a030d7381d8b3adabde724e3077bb6cb32d1b3ee
Gitweb: http://git.kernel.org/tip/a030d7381d8b3adabde724e3077bb6cb32d1b3ee
Author: Viresh Kumar 
AuthorDate: Wed, 24 May 2017 10:59:52 +0530
Committer:  Ingo Molnar 
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 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Vincent Guittot 
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 
---
 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 (_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 (_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