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Date: Fri, 06 Nov 2015 15:02:45 +0300
From: Arseniy Krasnov <a.krasnov@...sung.com>
To: linux@....linux.org.uk, mingo@...hat.com, peterz@...radead.org
Cc: a.krasnov@...sung.com, v.tyrtov@...sung.com,
s.rogachev@...sung.com, linux-kernel@...r.kernel.org,
Tarek Dakhran <t.dakhran@...sung.com>,
Sergey Dyasly <s.dyasly@...sung.com>,
Dmitriy Safonov <d.safonov@...tner.samsung.com>,
Ilya Maximets <i.maximets@...sung.com>
Subject: [PATCH 11/13] hperf_hmp: task CPU selection logic.
Adds new runqueue selection logic. If task is newly woken(fork or exec)
or it is not WF_SYNC wakeup, idlest CPU from both clusters is selected. Else,
default wake up logic is used('want_affine'). If it fails, idlest CPU from both
clusters is selected.
Signed-off-by: Tarek Dakhran <t.dakhran@...sung.com>
Signed-off-by: Sergey Dyasly <s.dyasly@...sung.com>
Signed-off-by: Dmitriy Safonov <d.safonov@...tner.samsung.com>
Signed-off-by: Arseniy Krasnov <a.krasnov@...sung.com>
Signed-off-by: Ilya Maximets <i.maximets@...sung.com>
---
kernel/sched/fair.c | 132 ++++++++++++++++++++++++++++++++++++++++------------
1 file changed, 101 insertions(+), 31 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index fd16729..79be023 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4798,6 +4798,62 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
return 1;
}
+#ifdef CONFIG_HPERF_HMP
+/**
+ * hmp_select_task_rq_fair(): selects cpu for task.
+ * @p: task which needs cpu
+ *
+ * Returns cpu for task.
+ *
+ * Selects idlest cpu for task @p.
+ */
+static int
+hmp_select_task_rq_fair(struct task_struct *p)
+{
+ int cpu;
+ int new_cpu;
+ unsigned long load;
+ unsigned long scaled_load;
+
+ new_cpu = task_cpu(p);
+
+ load = ULONG_MAX;
+ /* First check primary cpus */
+ for_each_cpu_and(cpu, cpu_online_mask, cpu_fastest_mask) {
+ if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) {
+ /* Select idle cpu if it exists */
+ if (idle_cpu(cpu))
+ return cpu;
+ /* Otherwise select the least loaded cpu */
+ scaled_load = (weighted_cpuload(cpu) *
+ SCHED_CAPACITY_SCALE) /
+ freq_scale_cpu_power[cpu];
+ if (scaled_load < load) {
+ new_cpu = cpu;
+ load = scaled_load;
+ }
+ }
+ }
+
+ /* Then check secondary cpus */
+ for_each_cpu_and(cpu, cpu_online_mask, cpu_slowest_mask) {
+ if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) {
+ if (idle_cpu(cpu))
+ return cpu;
+ scaled_load = (weighted_cpuload(cpu) *
+ SCHED_CAPACITY_SCALE) /
+ freq_scale_cpu_power[cpu];
+ if (scaled_load < load) {
+ new_cpu = cpu;
+ load = scaled_load;
+ }
+ }
+ }
+
+ return new_cpu;
+}
+
+#else /* CONFIG_HPERF_HMP */
/*
* find_idlest_group finds and returns the least busy CPU group within the
* domain.
@@ -4905,6 +4961,7 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
return shallowest_idle_cpu != -1 ? shallowest_idle_cpu : least_loaded_cpu;
}
+#endif /* CONFIG_HPERF_HMP */
/*
* Try and locate an idle CPU in the sched_domain.
*/
@@ -4998,6 +5055,11 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
int want_affine = 0;
int sync = wake_flags & WF_SYNC;
+#ifdef CONFIG_HPERF_HMP
+ if (!(sd_flag & SD_BALANCE_WAKE) || !sync)
+ return hmp_select_task_rq_fair(p);
+#endif
+
if (sd_flag & SD_BALANCE_WAKE)
want_affine = !wake_wide(p) && cpumask_test_cpu(cpu, tsk_cpus_allowed(p));
@@ -5030,41 +5092,49 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
if (!sd) {
if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
- new_cpu = select_idle_sibling(p, new_cpu);
-
- } else while (sd) {
- struct sched_group *group;
- int weight;
+ if (IS_ENABLED(CONFIG_HPERF_HMP) && sync)
+ new_cpu = prev_cpu;
+ else
+ new_cpu = select_idle_sibling(p, prev_cpu);
+ } else {
+#ifdef CONFIG_HPERF_HMP
+ new_cpu = hmp_select_task_rq_fair(p);
+#else
+ while (sd) {
+ struct sched_group *group;
+ int weight;
- if (!(sd->flags & sd_flag)) {
- sd = sd->child;
- continue;
- }
+ if (!(sd->flags & sd_flag)) {
+ sd = sd->child;
+ continue;
+ }
- group = find_idlest_group(sd, p, cpu, sd_flag);
- if (!group) {
- sd = sd->child;
- continue;
- }
+ group = find_idlest_group(sd, p, cpu, sd_flag);
+ if (!group) {
+ sd = sd->child;
+ continue;
+ }
- new_cpu = find_idlest_cpu(group, p, cpu);
- if (new_cpu == -1 || new_cpu == cpu) {
- /* Now try balancing at a lower domain level of cpu */
- sd = sd->child;
- continue;
- }
+ new_cpu = find_idlest_cpu(group, p, cpu);
+ if (new_cpu == -1 || new_cpu == cpu) {
+ /* Now try balancing at a lower domain level of cpu */
+ sd = sd->child;
+ continue;
+ }
- /* Now try balancing at a lower domain level of new_cpu */
- cpu = new_cpu;
- weight = sd->span_weight;
- sd = NULL;
- for_each_domain(cpu, tmp) {
- if (weight <= tmp->span_weight)
- break;
- if (tmp->flags & sd_flag)
- sd = tmp;
- }
- /* while loop will break here if sd == NULL */
+ /* Now try balancing at a lower domain level of new_cpu */
+ cpu = new_cpu;
+ weight = sd->span_weight;
+ sd = NULL;
+ for_each_domain(cpu, tmp) {
+ if (weight <= tmp->span_weight)
+ break;
+ if (tmp->flags & sd_flag)
+ sd = tmp;
+ }
+ /* while loop will break here if sd == NULL */
+ }
+#endif
}
rcu_read_unlock();
--
1.9.1
--
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