lkml.org 
[lkml]   [2022]   [Oct]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip: sched/core] sched/uclamp: Cater for uclamp in find_energy_efficient_cpu()'s early exit condition
The following commit has been merged into the sched/core branch of tip:

Commit-ID: d81304bc6193554014d4372a01debdf65e1e9a4d
Gitweb: https://git.kernel.org/tip/d81304bc6193554014d4372a01debdf65e1e9a4d
Author: Qais Yousef <qais.yousef@arm.com>
AuthorDate: Thu, 04 Aug 2022 15:36:07 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Thu, 27 Oct 2022 11:01:19 +02:00

sched/uclamp: Cater for uclamp in find_energy_efficient_cpu()'s early exit condition

If the utilization of the woken up task is 0, we skip the energy
calculation because it has no impact.

But if the task is boosted (uclamp_min != 0) will have an impact on task
placement and frequency selection. Only skip if the util is truly
0 after applying uclamp values.

Change uclamp_task_cpu() signature to avoid unnecessary additional calls
to uclamp_eff_get(). feec() is the only user now.

Fixes: 732cd75b8c920 ("sched/fair: Select an energy-efficient CPU on task wake-up")
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220804143609.515789-8-qais.yousef@arm.com
---
kernel/sched/fair.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a0ee319..0f32acb 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4280,14 +4280,16 @@ static inline unsigned long task_util_est(struct task_struct *p)
}

#ifdef CONFIG_UCLAMP_TASK
-static inline unsigned long uclamp_task_util(struct task_struct *p)
+static inline unsigned long uclamp_task_util(struct task_struct *p,
+ unsigned long uclamp_min,
+ unsigned long uclamp_max)
{
- return clamp(task_util_est(p),
- uclamp_eff_value(p, UCLAMP_MIN),
- uclamp_eff_value(p, UCLAMP_MAX));
+ return clamp(task_util_est(p), uclamp_min, uclamp_max);
}
#else
-static inline unsigned long uclamp_task_util(struct task_struct *p)
+static inline unsigned long uclamp_task_util(struct task_struct *p,
+ unsigned long uclamp_min,
+ unsigned long uclamp_max)
{
return task_util_est(p);
}
@@ -7205,7 +7207,7 @@ static int find_energy_efficient_cpu(struct task_struct *p, int prev_cpu)
target = prev_cpu;

sync_entity_load_avg(&p->se);
- if (!task_util_est(p))
+ if (!uclamp_task_util(p, p_util_min, p_util_max))
goto unlock;

eenv_task_busy_time(&eenv, p, prev_cpu);
\
 
 \ /
  Last update: 2022-10-28 08:45    [W:1.057 / U:0.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site