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Message-Id: <20220804143609.515789-8-qais.yousef@arm.com>
Date: Thu, 4 Aug 2022 15:36:07 +0100
From: Qais Yousef <qais.yousef@....com>
To: Ingo Molnar <mingo@...nel.org>,
"Peter Zijlstra (Intel)" <peterz@...radead.org>,
Vincent Guittot <vincent.guittot@...aro.org>,
Dietmar Eggemann <dietmar.eggemann@....com>
Cc: linux-kernel@...r.kernel.org, Xuewen Yan <xuewen.yan94@...il.com>,
Lukasz Luba <lukasz.luba@....com>, Wei Wang <wvw@...gle.com>,
Jonathan JMChen <Jonathan.JMChen@...iatek.com>,
Hank <han.lin@...iatek.com>, Qais Yousef <qais.yousef@....com>
Subject: [PATCH v2 7/9] 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@....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 4c3a5240d7e3..59ba7106ddc6 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4108,14 +4108,16 @@ 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);
}
@@ -7029,7 +7031,7 @@ 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);
--
2.25.1
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