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Diffstat (limited to '')
| -rw-r--r-- | kernel/sched/stats.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c new file mode 100644 index 000000000..857f837f5 --- /dev/null +++ b/kernel/sched/stats.c @@ -0,0 +1,231 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * /proc/schedstat implementation + */ + +void __update_stats_wait_start(struct rq *rq, struct task_struct *p, + struct sched_statistics *stats) +{ + u64 wait_start, prev_wait_start; + + wait_start = rq_clock(rq); + prev_wait_start = schedstat_val(stats->wait_start); + + if (p && likely(wait_start > prev_wait_start)) + wait_start -= prev_wait_start; + + __schedstat_set(stats->wait_start, wait_start); +} + +void __update_stats_wait_end(struct rq *rq, struct task_struct *p, + struct sched_statistics *stats) +{ + u64 delta = rq_clock(rq) - schedstat_val(stats->wait_start); + + if (p) { + if (task_on_rq_migrating(p)) { + /* + * Preserve migrating task's wait time so wait_start + * time stamp can be adjusted to accumulate wait time + * prior to migration. + */ + __schedstat_set(stats->wait_start, delta); + + return; + } + + trace_sched_stat_wait(p, delta); + } + + __schedstat_set(stats->wait_max, + max(schedstat_val(stats->wait_max), delta)); + __schedstat_inc(stats->wait_count); + __schedstat_add(stats->wait_sum, delta); + __schedstat_set(stats->wait_start, 0); +} + +void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p, + struct sched_statistics *stats) +{ + u64 sleep_start, block_start; + + sleep_start = schedstat_val(stats->sleep_start); + block_start = schedstat_val(stats->block_start); + + if (sleep_start) { + u64 delta = rq_clock(rq) - sleep_start; + + if ((s64)delta < 0) + delta = 0; + + if (unlikely(delta > schedstat_val(stats->sleep_max))) + __schedstat_set(stats->sleep_max, delta); + + __schedstat_set(stats->sleep_start, 0); + __schedstat_add(stats->sum_sleep_runtime, delta); + + if (p) { + account_scheduler_latency(p, delta >> 10, 1); + trace_sched_stat_sleep(p, delta); + } + } + + if (block_start) { + u64 delta = rq_clock(rq) - block_start; + + if ((s64)delta < 0) + delta = 0; + + if (unlikely(delta > schedstat_val(stats->block_max))) + __schedstat_set(stats->block_max, delta); + + __schedstat_set(stats->block_start, 0); + __schedstat_add(stats->sum_sleep_runtime, delta); + __schedstat_add(stats->sum_block_runtime, delta); + + if (p) { + if (p->in_iowait) { + __schedstat_add(stats->iowait_sum, delta); + __schedstat_inc(stats->iowait_count); + trace_sched_stat_iowait(p, delta); + } + + trace_sched_stat_blocked(p, delta); + + /* + * Blocking time is in units of nanosecs, so shift by + * 20 to get a milliseconds-range estimation of the + * amount of time that the task spent sleeping: + */ + if (unlikely(prof_on == SLEEP_PROFILING)) { + profile_hits(SLEEP_PROFILING, + (void *)get_wchan(p), + delta >> 20); + } + account_scheduler_latency(p, delta >> 10, 0); + } + } +} + +/* + * Current schedstat API version. + * + * Bump this up when changing the output format or the meaning of an existing + * format, so that tools can adapt (or abort) + */ +#define SCHEDSTAT_VERSION 15 + +static int show_schedstat(struct seq_file *seq, void *v) +{ + int cpu; + + if (v == (void *)1) { + seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION); + seq_printf(seq, "timestamp %lu\n", jiffies); + } else { + struct rq *rq; +#ifdef CONFIG_SMP + struct sched_domain *sd; + int dcount = 0; +#endif + cpu = (unsigned long)(v - 2); + rq = cpu_rq(cpu); + + /* runqueue-specific stats */ + seq_printf(seq, + "cpu%d %u 0 %u %u %u %u %llu %llu %lu", + cpu, rq->yld_count, + rq->sched_count, rq->sched_goidle, + rq->ttwu_count, rq->ttwu_local, + rq->rq_cpu_time, + rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount); + + seq_printf(seq, "\n"); + +#ifdef CONFIG_SMP + /* domain-specific stats */ + rcu_read_lock(); + for_each_domain(cpu, sd) { + enum cpu_idle_type itype; + + seq_printf(seq, "domain%d %*pb", dcount++, + cpumask_pr_args(sched_domain_span(sd))); + for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES; + itype++) { + seq_printf(seq, " %u %u %u %u %u %u %u %u", + sd->lb_count[itype], + sd->lb_balanced[itype], + sd->lb_failed[itype], + sd->lb_imbalance[itype], + sd->lb_gained[itype], + sd->lb_hot_gained[itype], + sd->lb_nobusyq[itype], + sd->lb_nobusyg[itype]); + } + seq_printf(seq, + " %u %u %u %u %u %u %u %u %u %u %u %u\n", + sd->alb_count, sd->alb_failed, sd->alb_pushed, + sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed, + sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed, + sd->ttwu_wake_remote, sd->ttwu_move_affine, + sd->ttwu_move_balance); + } + rcu_read_unlock(); +#endif + } + return 0; +} + +/* + * This iterator needs some explanation. + * It returns 1 for the header position. + * This means 2 is cpu 0. + * In a hotplugged system some CPUs, including cpu 0, may be missing so we have + * to use cpumask_* to iterate over the CPUs. + */ +static void *schedstat_start(struct seq_file *file, loff_t *offset) +{ + unsigned long n = *offset; + + if (n == 0) + return (void *) 1; + + n--; + + if (n > 0) + n = cpumask_next(n - 1, cpu_online_mask); + else + n = cpumask_first(cpu_online_mask); + + *offset = n + 1; + + if (n < nr_cpu_ids) + return (void *)(unsigned long)(n + 2); + + return NULL; +} + +static void *schedstat_next(struct seq_file *file, void *data, loff_t *offset) +{ + (*offset)++; + + return schedstat_start(file, offset); +} + +static void schedstat_stop(struct seq_file *file, void *data) +{ +} + +static const struct seq_operations schedstat_sops = { + .start = schedstat_start, + .next = schedstat_next, + .stop = schedstat_stop, + .show = show_schedstat, +}; + +static int __init proc_schedstat_init(void) +{ + proc_create_seq("schedstat", 0, NULL, &schedstat_sops); + return 0; +} +subsys_initcall(proc_schedstat_init); |