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

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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: 732cd75b8c ("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
This commit is contained in:
Qais Yousef 2022-08-04 15:36:07 +01:00 committed by Peter Zijlstra
parent c56ab1b350
commit d81304bc61
1 changed files with 8 additions and 6 deletions
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14
kernel/sched/fair.c
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@ -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);