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hperf_hmp: is_hmp_imbalance introduced.

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cases are possible: balancing from/to one of clusters, task swap(when clusters
are balanced) or skip rebalance. Function calculates load difference between two
cluster(cluster load / cluster power) and threshold when balancing is needed.

Signed-off-by: Tarek Dakhran <t.dakhran <at> samsung.com>
Signed-off-by: Sergey Dyasly <s.dyasly <at> samsung.com>
Signed-off-by: Dmitriy Safonov <d.safonov <at> partner.samsung.com>
Signed-off-by: Arseniy Krasnov <a.krasnov <at> samsung.com>
Signed-off-by: Ilya Maximets <i.maximets <at> samsung.com>
Signed-off-by: memeka <mihailescu2m@gmail.com>
This commit is contained in:
Arseniy Krasnov
2015-11-06 12:02:40 +00:00
committed by Mauro (mdrjr) Ribeiro
parent 9cfcccae3d
commit 62f3b069e4
1 changed files with 103 additions and 0 deletions
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103
kernel/sched/fair.c
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@@ -104,9 +104,21 @@ unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL;
extern void hmp_set_cpu_masks(struct cpumask *, struct cpumask *);
static atomic_t a15_nr_hmp_busy = ATOMIC_INIT(0);
static atomic_t a7_nr_hmp_busy = ATOMIC_INIT(0);
/* Total weight of all running tasks on A15 and A7 CPU domains */
static atomic_long_t a15_total_weight = ATOMIC_LONG_INIT(0);
static atomic_long_t a7_total_weight = ATOMIC_LONG_INIT(0);
static atomic_t hmp_imbalance = ATOMIC_INIT(0);
static unsigned int freq_scale_cpu_power[CONFIG_NR_CPUS];
enum hmp_balance_actions {
SWAP_TASKS,
A15_TO_A7,
A7_TO_A15,
SKIP_REBALANCE,
};
#endif /* CONFIG_HPERF_HMP */
#ifdef CONFIG_CFS_BANDWIDTH
@@ -7791,6 +7803,97 @@ static int should_we_balance(struct lb_env *env)
*/
return balance_cpu == env->dst_cpu;
}
#ifdef CONFIG_HPERF_HMP
/**
* is_hmp_imbalance(): Calculates imbalance between HMP domains.
* @sd: Current sched domain.
*
* Returns migration direction(see SWAP_TASKS, A15_TO_A7, A7_TO_A15,
* SKIP_REBALANCE).
*
* Imbalance depends on load of tasks on A15 cores and A7 cores,
* current CPU's frequencies, and A7 slowdown coefficient which is about 2.4.
*/
static int is_hmp_imbalance(struct sched_domain *sd)
{
int imbalance, cpu;
int a15_group_power = 0, a7_group_power = 0,
hmp_imbalance_min_threshold;
int a15_group_load, a7_group_load, a15_a7_group_power;
unsigned int a7_balanced_num;
int reminder, divisor;
unsigned int a15_balanced_num;
long long int hmp_imbalance_threshold;
if (!sd->a15_group) {
return SKIP_REBALANCE;
}
if (!sd->a7_group) {
return SKIP_REBALANCE;
}
for_each_online_cpu(cpu) {
if (cpu_is_fastest(cpu))
a15_group_power += freq_scale_cpu_power[cpu];
else
a7_group_power += freq_scale_cpu_power[cpu];
}
if (a15_group_power == 0 || a7_group_power == 0) {
return SKIP_REBALANCE;
}
a15_balanced_num = 0;
a7_balanced_num = 0;
for_each_online_cpu(cpu) {
if (cpu_rq(cpu)->cfs.h_nr_running <= 1) {
if (cpu_is_fastest(cpu))
a15_balanced_num++;
else
a7_balanced_num++;
}
}
a7_group_load = atomic_long_read(&a7_total_weight);
if (atomic_long_read(&a7_total_weight) == 0 &&
(a15_balanced_num == sd->a15_group->group_weight)) {
return SKIP_REBALANCE;
}
a15_group_load = atomic_long_read(&a15_total_weight);
a15_a7_group_power = a15_group_power + a7_group_power;
imbalance = (a15_group_load * 1024) / (a15_group_power) -
(a7_group_load * 1024) / (a7_group_power);
hmp_imbalance_threshold = ((long long int)NICE_0_LOAD *
1024 * a15_a7_group_power);
divisor = 2 * a15_group_power * a7_group_power;
hmp_imbalance_threshold = div_s64_rem(hmp_imbalance_threshold,
divisor, &reminder);
hmp_imbalance_min_threshold = hmp_imbalance_threshold >> 3;
if (imbalance < hmp_imbalance_min_threshold &&
imbalance > -hmp_imbalance_min_threshold) {
atomic_set(&hmp_imbalance, 0);
return SKIP_REBALANCE;
}
if (imbalance > hmp_imbalance_threshold) {
return A15_TO_A7;
} else {
if (imbalance < -hmp_imbalance_threshold) {
if (a7_balanced_num == sd->a7_group->group_weight)
return SWAP_TASKS;
else
return A7_TO_A15;
} else {
return SWAP_TASKS;
}
}
}
#endif /* CONFIG_HPERF_HMP */
/*
* Check this_cpu to ensure it is balanced within domain. Attempt to move