调度器18—/proc/schedstat文件

一、打印说明

1. 打印文件 kernel/sched/stats.c

// SPDX-License-Identifier: GPL-2.0
/*
 * /proc/schedstat implementation, kernel/sched/stats.c
 */
#include "sched.h"

/*
 * 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 itererator 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);

2. 打印格式

# cat /proc/schedstat
version 15
timestamp 4299704439
cpu0 45138 0 542397 168341 2109253 149554 211881422606 111767530843 330385
domain0 0f 227641 224888 1633 422336 1219 17 3 224887 2153 1760 268 388564 233 4 0 1760 73662 62207 2826 16446 8629 0 3 62204 19 0 19 0 0 0 0 0 0 152749 6486 0
domain1 ff 173232 172862 297 152593 116 3 17 143952 1005 1000 0 25484 7 0 1 261 64513 62039 1620 692752 854 6 192 61847 1 0 1 0 0 0 0 0 0 1806952 8003 0
cpu1 45841 0 624737 207959 238253 89621 324903926519 116922840103 373278
domain0 0f 173648 170909 1025 413908 1784 22 1 170941 9388 8952 273 464751 273 6 1 8951 81913 70676 2878 41542 8359 4 3 70673 21 0 21 0 0 0 0 0 0 72591 5884 0
domain1 ff 133941 133783 104 38284 59 1 9 4621 3319 3319 0 0 0 0 0 0 73117 70478 1762 858868 877 0 178 70300 0 0 0 0 0 0 0 0 0 76041 7324 0
cpu2 51178 0 321468 71432 126760 48041 161480944503 94681870241 202908
domain0 0f 189232 184881 2163 490574 2324 33 2 184881 1263 820 289 403211 246 5 0 820 42119 32517 2393 15705 7209 2 2 32515 33 1 32 0 0 0 0 0 0 40358 6456 0
domain1 ff 143982 143908 43 24175 49 0 5 1340 532 532 0 0 0 0 0 0 34564 32329 1406 638964 829 0 180 32149 0 0 0 0 0 0 0 0 0 38361 7785 0
cpu3 35501 0 565446 192840 273957 83773 337833473407 121948859432 340993
domain0 0f 177897 175874 1149 167989 974 20 0 175873 8620 8170 289 327360 288 5 0 8170 71849 61682 2271 13143 7896 2 5 61677 22 0 22 0 0 0 0 0 0 79642 5715 0
domain1 ff 136929 136891 22 6872 35 1 3 482 5531 5531 0 0 0 0 0 0 63573 61254 1590 774906 729 0 119 61135 0 0 0 0 0 0 0 0 0 110542 5091 0
cpu4 27314 0 4131892 1759198 1846940 1410620 492045817989 272120457957 2331643
domain0 70 318277 307849 2580 42250 8712 1 3 307850 6953 6823 25 256628 224 0 1 6822 175848 106984 15687 116797 53177 3 3 106970 0 0 0 0 0 0 0 0 0 336853 7759 0
domain1 ff 82908 80926 1806 2383686 446 255 8 67670 409 335 54 748960 32 0 0 92 121846 100176 20364 14634247 1306 24 339 99837 274 23 251 0 0 0 0 0 0 99467 5856 0
cpu5 28142 0 15038899 7208189 6659568 6139758 1042148156910 266948961272 7783970
domain0 70 559016 550747 2238 42294 6887 2 1 550747 6026 5876 18 265564 308 0 2 5874 192275 122809 17145 119657 52321 3 1 122796 0 0 0 0 0 0 0 0 0 383241 7752 0
domain1 ff 272867 272091 695 792819 299 206 9 15905 430 430 0 0 0 0 0 0 138634 113585 23877 25276253 1172 10 282 113303 231 29 202 0 0 0 0 0 0 136569 6039 0
cpu6 21540 0 5412884 2397119 2410659 1938283 595211270931 269219056980 2977818
domain0 70 385866 377440 2536 68482 6719 0 2 377449 8519 8384 23 285279 262 0 0 8384 180564 110492 18169 116184 51903 2 4 110484 0 0 0 0 0 0 0 0 0 368876 7967 0
domain1 ff 248297 247825 430 619453 295 220 5 6035 696 696 0 0 0 0 0 0 127391 103044 23221 24362600 1126 14 335 102709 247 25 222 0 0 0 0 0 0 103500 6013 0
cpu7 21675 0 379280 116596 213543 101590 116532614349 54500059021 242622
domain0 ff 55862 54336 1446 749920 334 210 17 54319 220 116 71 487137 82 1 1 115 25738 14742 9617 4602503 1379 20 392 14350 232 19 213 0 0 0 0 0 0 111953 324 0

3. 总结：打印每个cpu rq 上的部分信息和 load balance 统计信息。