kernel/sched/stats.c

   1
   2 #include <linux/slab.h>
   3 #include <linux/fs.h>
   4 #include <linux/seq_file.h>
   5 #include <linux/proc_fs.h>
   6
   7 #include "sched.h"
   8
   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
  15 static int show_schedstat(struct seq_file *seq, void *v)
  16 {
  17         int cpu;
  18         int mask_len = DIV_ROUND_UP(NR_CPUS, 32) * 9;
  19         char *mask_str = kmalloc(mask_len, GFP_KERNEL);
  20
  21         if (mask_str == NULL)
  22                 return -ENOMEM;
  23
  24         if (v == (void *)1) {
  25                 seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
  26                 seq_printf(seq, "timestamp %lu\n", jiffies);
  27         } else {
  28                 struct rq *rq;
  29 #ifdef CONFIG_SMP
  30                 struct sched_domain *sd;
  31                 int dcount = 0;
  32 #endif
  33                 cpu = (unsigned long)(v - 2);
  34                 rq = cpu_rq(cpu);
  35
  36                 /* runqueue-specific stats */
  37                 seq_printf(seq,
  38                     "cpu%d %u 0 %u %u %u %u %llu %llu %lu",
  39                     cpu, rq->yld_count,
  40                     rq->sched_count, rq->sched_goidle,
  41                     rq->ttwu_count, rq->ttwu_local,
  42                     rq->rq_cpu_time,
  43                     rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);
  44
  45                 seq_printf(seq, "\n");
  46
  47 #ifdef CONFIG_SMP
  48                 /* domain-specific stats */
  49                 rcu_read_lock();
  50                 for_each_domain(cpu, sd) {
  51                         enum cpu_idle_type itype;
  52
  53                         cpumask_scnprintf(mask_str, mask_len,
  54                                           sched_domain_span(sd));
  55                         seq_printf(seq, "domain%d %s", dcount++, mask_str);
  56                         for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES;
  57                                         itype++) {
  58                                 seq_printf(seq, " %u %u %u %u %u %u %u %u",
  59                                     sd->lb_count[itype],
  60                                     sd->lb_balanced[itype],
  61                                     sd->lb_failed[itype],
  62                                     sd->lb_imbalance[itype],
  63                                     sd->lb_gained[itype],
  64                                     sd->lb_hot_gained[itype],
  65                                     sd->lb_nobusyq[itype],
  66                                     sd->lb_nobusyg[itype]);
  67                         }
  68                         seq_printf(seq,
  69                                    " %u %u %u %u %u %u %u %u %u %u %u %u\n",
  70                             sd->alb_count, sd->alb_failed, sd->alb_pushed,
  71                             sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,
  72                             sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
  73                             sd->ttwu_wake_remote, sd->ttwu_move_affine,
  74                             sd->ttwu_move_balance);
  75                 }
  76                 rcu_read_unlock();
  77 #endif
  78         }
  79         kfree(mask_str);
  80         return 0;
  81 }
  82
  83 /*
  84  * This itererator needs some explanation.
  85  * It returns 1 for the header position.
  86  * This means 2 is cpu 0.
  87  * In a hotplugged system some cpus, including cpu 0, may be missing so we have
  88  * to use cpumask_* to iterate over the cpus.
  89  */
  90 static void *schedstat_start(struct seq_file *file, loff_t *offset)
  91 {
  92         unsigned long n = *offset;
  93
  94         if (n == 0)
  95                 return (void *) 1;
  96
  97         n--;
  98
  99         if (n > 0)
 100                 n = cpumask_next(n - 1, cpu_online_mask);
 101         else
 102                 n = cpumask_first(cpu_online_mask);
 103
 104         *offset = n + 1;
 105
 106         if (n < nr_cpu_ids)
 107                 return (void *)(unsigned long)(n + 2);
 108         return NULL;
 109 }
 110
 111 static void *schedstat_next(struct seq_file *file, void *data, loff_t *offset)
 112 {
 113         (*offset)++;
 114         return schedstat_start(file, offset);
 115 }
 116
 117 static void schedstat_stop(struct seq_file *file, void *data)
 118 {
 119 }
 120
 121 static const struct seq_operations schedstat_sops = {
 122         .start = schedstat_start,
 123         .next  = schedstat_next,
 124         .stop  = schedstat_stop,
 125         .show  = show_schedstat,
 126 };
 127
 128 static int schedstat_open(struct inode *inode, struct file *file)
 129 {
 130         return seq_open(file, &schedstat_sops);
 131 }
 132
 133 static const struct file_operations proc_schedstat_operations = {
 134         .open    = schedstat_open,
 135         .read    = seq_read,
 136         .llseek  = seq_lseek,
 137         .release = seq_release,
 138 };
 139
 140 static int __init proc_schedstat_init(void)
 141 {
 142         proc_create("schedstat", 0, NULL, &proc_schedstat_operations);
 143         return 0;
 144 }
 145 module_init(proc_schedstat_init);