LXR linux/kernel/sched/stats.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * /proc/schedstat implementation
   4 */
   5#include "sched.h"
   6
   7/*
   8 * Current schedstat API version.
   9 *
  10 * Bump this up when changing the output format or the meaning of an existing
  11 * format, so that tools can adapt (or abort)
  12 */
  13#define SCHEDSTAT_VERSION 15
  14
  15static int show_schedstat(struct seq_file *seq, void *v)
  16{
  17        int cpu;
  18
  19        if (v == (void *)1) {
  20                seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
  21                seq_printf(seq, "timestamp %lu\n", jiffies);
  22        } else {
  23                struct rq *rq;
  24#ifdef CONFIG_SMP
  25                struct sched_domain *sd;
  26                int dcount = 0;
  27#endif
  28                cpu = (unsigned long)(v - 2);
  29                rq = cpu_rq(cpu);
  30
  31                /* runqueue-specific stats */
  32                seq_printf(seq,
  33                    "cpu%d %u 0 %u %u %u %u %llu %llu %lu",
  34                    cpu, rq->yld_count,
  35                    rq->sched_count, rq->sched_goidle,
  36                    rq->ttwu_count, rq->ttwu_local,
  37                    rq->rq_cpu_time,
  38                    rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);
  39
  40                seq_printf(seq, "\n");
  41
  42#ifdef CONFIG_SMP
  43                /* domain-specific stats */
  44                rcu_read_lock();
  45                for_each_domain(cpu, sd) {
  46                        enum cpu_idle_type itype;
  47
  48                        seq_printf(seq, "domain%d %*pb", dcount++,
  49                                   cpumask_pr_args(sched_domain_span(sd)));
  50                        for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES;
  51                                        itype++) {
  52                                seq_printf(seq, " %u %u %u %u %u %u %u %u",
  53                                    sd->lb_count[itype],
  54                                    sd->lb_balanced[itype],
  55                                    sd->lb_failed[itype],
  56                                    sd->lb_imbalance[itype],
  57                                    sd->lb_gained[itype],
  58                                    sd->lb_hot_gained[itype],
  59                                    sd->lb_nobusyq[itype],
  60                                    sd->lb_nobusyg[itype]);
  61                        }
  62                        seq_printf(seq,
  63                                   " %u %u %u %u %u %u %u %u %u %u %u %u\n",
  64                            sd->alb_count, sd->alb_failed, sd->alb_pushed,
  65                            sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,
  66                            sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
  67                            sd->ttwu_wake_remote, sd->ttwu_move_affine,
  68                            sd->ttwu_move_balance);
  69                }
  70                rcu_read_unlock();
  71#endif
  72        }
  73        return 0;
  74}
  75
  76/*
  77 * This itererator needs some explanation.
  78 * It returns 1 for the header position.
  79 * This means 2 is cpu 0.
  80 * In a hotplugged system some CPUs, including cpu 0, may be missing so we have
  81 * to use cpumask_* to iterate over the CPUs.
  82 */
  83static void *schedstat_start(struct seq_file *file, loff_t *offset)
  84{
  85        unsigned long n = *offset;
  86
  87        if (n == 0)
  88                return (void *) 1;
  89
  90        n--;
  91
  92        if (n > 0)
  93                n = cpumask_next(n - 1, cpu_online_mask);
  94        else
  95                n = cpumask_first(cpu_online_mask);
  96
  97        *offset = n + 1;
  98
  99        if (n < nr_cpu_ids)
 100                return (void *)(unsigned long)(n + 2);
 101
 102        return NULL;
 103}
 104
 105static void *schedstat_next(struct seq_file *file, void *data, loff_t *offset)
 106{
 107        (*offset)++;
 108
 109        return schedstat_start(file, offset);
 110}
 111
 112static void schedstat_stop(struct seq_file *file, void *data)
 113{
 114}
 115
 116static const struct seq_operations schedstat_sops = {
 117        .start = schedstat_start,
 118        .next  = schedstat_next,
 119        .stop  = schedstat_stop,
 120        .show  = show_schedstat,
 121};
 122
 123static int __init proc_schedstat_init(void)
 124{
 125        proc_create_seq("schedstat", 0, NULL, &schedstat_sops);
 126        return 0;
 127}
 128subsys_initcall(proc_schedstat_init);
 129