diff options
Diffstat (limited to 'kernel/sched/sched_avg.c')
| -rw-r--r-- | kernel/sched/sched_avg.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/kernel/sched/sched_avg.c b/kernel/sched/sched_avg.c new file mode 100644 index 000000000000..29d8a26a78ed --- /dev/null +++ b/kernel/sched/sched_avg.c @@ -0,0 +1,129 @@ +/* Copyright (c) 2012, 2015-2016, The Linux Foundation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +/* + * Scheduler hook for average runqueue determination + */ +#include <linux/module.h> +#include <linux/percpu.h> +#include <linux/hrtimer.h> +#include <linux/sched.h> +#include <linux/math64.h> + +#include "sched.h" +#include <trace/events/sched.h> + +static DEFINE_PER_CPU(u64, nr_prod_sum); +static DEFINE_PER_CPU(u64, last_time); +static DEFINE_PER_CPU(u64, nr_big_prod_sum); +static DEFINE_PER_CPU(u64, nr); + +static DEFINE_PER_CPU(unsigned long, iowait_prod_sum); +static DEFINE_PER_CPU(spinlock_t, nr_lock) = __SPIN_LOCK_UNLOCKED(nr_lock); +static s64 last_get_time; + +/** + * sched_get_nr_running_avg + * @return: Average nr_running, iowait and nr_big_tasks value since last poll. + * Returns the avg * 100 to return up to two decimal points + * of accuracy. + * + * Obtains the average nr_running value since the last poll. + * This function may not be called concurrently with itself + */ +void sched_get_nr_running_avg(int *avg, int *iowait_avg, int *big_avg) +{ + int cpu; + u64 curr_time = sched_clock(); + u64 diff = curr_time - last_get_time; + u64 tmp_avg = 0, tmp_iowait = 0, tmp_big_avg = 0; + + *avg = 0; + *iowait_avg = 0; + *big_avg = 0; + + if (!diff) + return; + + /* read and reset nr_running counts */ + for_each_possible_cpu(cpu) { + unsigned long flags; + + spin_lock_irqsave(&per_cpu(nr_lock, cpu), flags); + curr_time = sched_clock(); + diff = curr_time - per_cpu(last_time, cpu); + BUG_ON((s64)diff < 0); + + tmp_avg += per_cpu(nr_prod_sum, cpu); + tmp_avg += per_cpu(nr, cpu) * diff; + + tmp_big_avg += per_cpu(nr_big_prod_sum, cpu); + tmp_big_avg += nr_eligible_big_tasks(cpu) * diff; + + tmp_iowait += per_cpu(iowait_prod_sum, cpu); + tmp_iowait += nr_iowait_cpu(cpu) * diff; + + per_cpu(last_time, cpu) = curr_time; + + per_cpu(nr_prod_sum, cpu) = 0; + per_cpu(nr_big_prod_sum, cpu) = 0; + per_cpu(iowait_prod_sum, cpu) = 0; + + spin_unlock_irqrestore(&per_cpu(nr_lock, cpu), flags); + } + + diff = curr_time - last_get_time; + last_get_time = curr_time; + + *avg = (int)div64_u64(tmp_avg * 100, diff); + *big_avg = (int)div64_u64(tmp_big_avg * 100, diff); + *iowait_avg = (int)div64_u64(tmp_iowait * 100, diff); + + trace_sched_get_nr_running_avg(*avg, *big_avg, *iowait_avg); + + BUG_ON(*avg < 0 || *big_avg < 0 || *iowait_avg < 0); + pr_debug("%s - avg:%d big_avg:%d iowait_avg:%d\n", + __func__, *avg, *big_avg, *iowait_avg); +} +EXPORT_SYMBOL(sched_get_nr_running_avg); + +/** + * sched_update_nr_prod + * @cpu: The core id of the nr running driver. + * @delta: Adjust nr by 'delta' amount + * @inc: Whether we are increasing or decreasing the count + * @return: N/A + * + * Update average with latest nr_running value for CPU + */ +void sched_update_nr_prod(int cpu, long delta, bool inc) +{ + u64 diff; + u64 curr_time; + unsigned long flags, nr_running; + + spin_lock_irqsave(&per_cpu(nr_lock, cpu), flags); + nr_running = per_cpu(nr, cpu); + curr_time = sched_clock(); + diff = curr_time - per_cpu(last_time, cpu); + BUG_ON((s64)diff < 0); + per_cpu(last_time, cpu) = curr_time; + per_cpu(nr, cpu) = nr_running + (inc ? delta : -delta); + + BUG_ON((s64)per_cpu(nr, cpu) < 0); + + per_cpu(nr_prod_sum, cpu) += nr_running * diff; + per_cpu(nr_big_prod_sum, cpu) += nr_eligible_big_tasks(cpu) * diff; + per_cpu(iowait_prod_sum, cpu) += nr_iowait_cpu(cpu) * diff; + spin_unlock_irqrestore(&per_cpu(nr_lock, cpu), flags); +} +EXPORT_SYMBOL(sched_update_nr_prod); |