[PATCH] sched/fair: calculate delta runnable load only when it's needed

[PATCH] sched/fair: calculate delta runnable load only when it's needed

[Peng Wang]

Move the code of calculation for delta_sum/delta_avg to where
it is really needed to be done.

Signed-off-by: Peng Wang <rocking@linux.alibaba.com>
---
 kernel/sched/fair.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ba749f579714..6b7e6b528e9b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3366,16 +3366,17 @@ update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cf
 
 	runnable_load_sum = (s64)se_runnable(se) * runnable_sum;
 	runnable_load_avg = div_s64(runnable_load_sum, LOAD_AVG_MAX);
-	delta_sum = runnable_load_sum - se_weight(se) * se->avg.runnable_load_sum;
-	delta_avg = runnable_load_avg - se->avg.runnable_load_avg;
-
-	se->avg.runnable_load_sum = runnable_sum;
-	se->avg.runnable_load_avg = runnable_load_avg;
 
 	if (se->on_rq) {
+		delta_sum = runnable_load_sum -
+				se_weight(se) * se->avg.runnable_load_sum;
+		delta_avg = runnable_load_avg - se->avg.runnable_load_avg;
 		add_positive(&cfs_rq->avg.runnable_load_avg, delta_avg);
 		add_positive(&cfs_rq->avg.runnable_load_sum, delta_sum);
 	}
+
+	se->avg.runnable_load_sum = runnable_sum;
+	se->avg.runnable_load_avg = runnable_load_avg;
 }
 
 static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum)
-- 
2.24.0

Re: [PATCH] sched/fair: calculate delta runnable load only when it's needed

[Vincent Guittot]

On Fri, 3 Jan 2020 at 12:45, Peng Wang <rocking@linux.alibaba.com> wrote:
>
> Move the code of calculation for delta_sum/delta_avg to where

Maybe precise that you move delta_sum/delta_avg for runnable_load_sum/avg

> it is really needed to be done.
>
> Signed-off-by: Peng Wang <rocking@linux.alibaba.com>

make sense to me

Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>

> ---
>  kernel/sched/fair.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index ba749f579714..6b7e6b528e9b 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -3366,16 +3366,17 @@ update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cf
>
>         runnable_load_sum = (s64)se_runnable(se) * runnable_sum;
>         runnable_load_avg = div_s64(runnable_load_sum, LOAD_AVG_MAX);
> -       delta_sum = runnable_load_sum - se_weight(se) * se->avg.runnable_load_sum;
> -       delta_avg = runnable_load_avg - se->avg.runnable_load_avg;
> -
> -       se->avg.runnable_load_sum = runnable_sum;
> -       se->avg.runnable_load_avg = runnable_load_avg;
>
>         if (se->on_rq) {
> +               delta_sum = runnable_load_sum -
> +                               se_weight(se) * se->avg.runnable_load_sum;
> +               delta_avg = runnable_load_avg - se->avg.runnable_load_avg;
>                 add_positive(&cfs_rq->avg.runnable_load_avg, delta_avg);
>                 add_positive(&cfs_rq->avg.runnable_load_sum, delta_sum);
>         }
> +
> +       se->avg.runnable_load_sum = runnable_sum;
> +       se->avg.runnable_load_avg = runnable_load_avg;
>  }
>
>  static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum)
> --
> 2.24.0
>

[tip: sched/core] sched/fair: calculate delta runnable load only when it's needed

[tip-bot2 for Peng Wang]

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     fe71bbb21ee14160f73f81b113d71145327a1c0d
Gitweb:        https://git.kernel.org/tip/fe71bbb21ee14160f73f81b113d71145327a1c0d
Author:        Peng Wang <rocking@linux.alibaba.com>
AuthorDate:    Fri, 03 Jan 2020 19:44:00 +08:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 17 Jan 2020 10:19:21 +01:00

sched/fair: calculate delta runnable load only when it's needed

Move the code of calculation for delta_sum/delta_avg to where
it is really needed to be done.

Signed-off-by: Peng Wang <rocking@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20200103114400.17668-1-rocking@linux.alibaba.com
---
 kernel/sched/fair.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d292883..32c5421 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3366,16 +3366,17 @@ update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cf
 
 	runnable_load_sum = (s64)se_runnable(se) * runnable_sum;
 	runnable_load_avg = div_s64(runnable_load_sum, LOAD_AVG_MAX);
-	delta_sum = runnable_load_sum - se_weight(se) * se->avg.runnable_load_sum;
-	delta_avg = runnable_load_avg - se->avg.runnable_load_avg;
-
-	se->avg.runnable_load_sum = runnable_sum;
-	se->avg.runnable_load_avg = runnable_load_avg;
 
 	if (se->on_rq) {
+		delta_sum = runnable_load_sum -
+				se_weight(se) * se->avg.runnable_load_sum;
+		delta_avg = runnable_load_avg - se->avg.runnable_load_avg;
 		add_positive(&cfs_rq->avg.runnable_load_avg, delta_avg);
 		add_positive(&cfs_rq->avg.runnable_load_sum, delta_sum);
 	}
+
+	se->avg.runnable_load_sum = runnable_sum;
+	se->avg.runnable_load_avg = runnable_load_avg;
 }
 
 static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum)