From 28e8cb961c2f71a89e391335a9304c3dd8b38d8f Mon Sep 17 00:00:00 2001 From: Patrick Bellasi Date: Thu, 28 Jul 2016 16:39:27 +0100 Subject: [PATCH] FIX: sched/tune: update usage of boosted task utilisation on CPU selection A boosted task needs to be scheduled on a CPU which can grant a minimum capacity which is higher than its utilization. However, a task can be allocated on a CPU which already provides an utilization which is higher than the task boosted utilization itself. Moreover, with the previous approach a task 100% boosted is not fitting any CPU. This patch makes use of the boosted task utilization just as a threashold which defines the minimum capacity should be available on a CPU to host that task. Signed-off-by: Patrick Bellasi --- kernel/sched/fair.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 88aca75a6659..9e1935b6e340 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5636,6 +5636,7 @@ static int energy_aware_wake_cpu(struct task_struct *p, int target, int sync) struct sched_group *sg, *sg_target; int target_max_cap = INT_MAX; int target_cpu = task_cpu(p); + unsigned long task_util_boosted, new_util; int i; if (sysctl_sched_sync_hint_enable && sync) { @@ -5679,6 +5680,7 @@ static int energy_aware_wake_cpu(struct task_struct *p, int target, int sync) } } while (sg = sg->next, sg != sd->groups); + task_util_boosted = boosted_task_util(p); /* Find cpu with sufficient capacity */ for_each_cpu_and(i, tsk_cpus_allowed(p), sched_group_cpus(sg_target)) { /* @@ -5686,8 +5688,13 @@ static int energy_aware_wake_cpu(struct task_struct *p, int target, int sync) * so prev_cpu will receive a negative bias due to the double * accounting. However, the blocked utilization may be zero. */ - int new_util = cpu_util(i) + boosted_task_util(p); + new_util = cpu_util(i) + task_util_boosted; + /* + * Ensure minimum capacity to grant the required boost. + * The target CPU can be already at a capacity level higher + * than the one required to boost the task. + */ if (new_util > capacity_orig_of(i)) continue;