This is a note to let you know that I've just added the patch titled
sched/uclamp: Make cpu_overutilized() use util_fits_cpu()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sched-uclamp-make-cpu_overutilized-use-util_fits_cpu.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From stable-owner@xxxxxxxxxxxxxxx Tue Apr 18 16:06:04 2023
From: Qais Yousef <qyousef@xxxxxxxxxxx>
Date: Tue, 18 Apr 2023 15:05:42 +0100
Subject: sched/uclamp: Make cpu_overutilized() use util_fits_cpu()
To: stable@xxxxxxxxxxxxxxx, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>, Vincent Guittot <vincent.guittot@xxxxxxxxxx>, Dietmar Eggemann <dietmar.eggemann@xxxxxxx>, Qais Yousef <qais.yousef@xxxxxxx>
Message-ID: <20230418140547.88035-3-qyousef@xxxxxxxxxxx>
From: Qais Yousef <qyousef@xxxxxxxxxxx>
From: Qais Yousef <qais.yousef@xxxxxxx>
commit c56ab1b3506ba0e7a872509964b100912bde165d upstream.
So that it is now uclamp aware.
This fixes a major problem of busy tasks capped with UCLAMP_MAX keeping
the system in overutilized state which disables EAS and leads to wasting
energy in the long run.
Without this patch running a busy background activity like JIT
compilation on Pixel 6 causes the system to be in overutilized state
74.5% of the time.
With this patch this goes down to 9.79%.
It also fixes another problem when long running tasks that have their
UCLAMP_MIN changed while running such that they need to upmigrate to
honour the new UCLAMP_MIN value. The upmigration doesn't get triggered
because overutilized state never gets set in this state, hence misfit
migration never happens at tick in this case until the task wakes up
again.
Fixes: af24bde8df202 ("sched/uclamp: Add uclamp support to energy_compute()")
Signed-off-by: Qais Yousef <qais.yousef@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220804143609.515789-7-qais.yousef@xxxxxxx
(cherry picked from commit c56ab1b3506ba0e7a872509964b100912bde165d)
[Fixed trivial conflict in cpu_overutilized() - use cpu_util() instead
of cpu_util_cfs()]
Signed-off-by: Qais Yousef (Google) <qyousef@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/sched/fair.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5739,7 +5739,10 @@ static inline unsigned long cpu_util(int
static inline bool cpu_overutilized(int cpu)
{
- return !fits_capacity(cpu_util(cpu), capacity_of(cpu));
+ unsigned long rq_util_min = uclamp_rq_get(cpu_rq(cpu), UCLAMP_MIN);
+ unsigned long rq_util_max = uclamp_rq_get(cpu_rq(cpu), UCLAMP_MAX);
+
+ return !util_fits_cpu(cpu_util(cpu), rq_util_min, rq_util_max, cpu);
}
static inline void update_overutilized_status(struct rq *rq)
Patches currently in stable-queue which might be from stable-owner@xxxxxxxxxxxxxxx are
queue-5.15/sched-fair-detect-capacity-inversion.patch
queue-5.15/sched-uclamp-make-cpu_overutilized-use-util_fits_cpu.patch
queue-5.15/sched-uclamp-fix-fits_capacity-check-in-feec.patch
queue-5.15/sched-fair-consider-capacity-inversion-in-util_fits_cpu.patch
queue-5.15/sched-fair-fixes-for-capacity-inversion-detection.patch
queue-5.15/sched-uclamp-fix-a-uninitialized-variable-warnings.patch
queue-5.15/sched-uclamp-cater-for-uclamp-in-find_energy_efficient_cpu-s-early-exit-condition.patch
