1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * /proc/schedstat implementation 4 */ 5 #include "sched.h" 6 7 void __update_stats_wait_start(struct rq *rq, struct task_struct *p, 8 struct sched_statistics *stats) 9 { 10 u64 wait_start, prev_wait_start; 11 12 wait_start = rq_clock(rq); 13 prev_wait_start = schedstat_val(stats->wait_start); 14 15 if (p && likely(wait_start > prev_wait_start)) 16 wait_start -= prev_wait_start; 17 18 __schedstat_set(stats->wait_start, wait_start); 19 } 20 21 void __update_stats_wait_end(struct rq *rq, struct task_struct *p, 22 struct sched_statistics *stats) 23 { 24 u64 delta = rq_clock(rq) - schedstat_val(stats->wait_start); 25 26 if (p) { 27 if (task_on_rq_migrating(p)) { 28 /* 29 * Preserve migrating task's wait time so wait_start 30 * time stamp can be adjusted to accumulate wait time 31 * prior to migration. 32 */ 33 __schedstat_set(stats->wait_start, delta); 34 35 return; 36 } 37 38 trace_sched_stat_wait(p, delta); 39 } 40 41 __schedstat_set(stats->wait_max, 42 max(schedstat_val(stats->wait_max), delta)); 43 __schedstat_inc(stats->wait_count); 44 __schedstat_add(stats->wait_sum, delta); 45 __schedstat_set(stats->wait_start, 0); 46 } 47 48 void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p, 49 struct sched_statistics *stats) 50 { 51 u64 sleep_start, block_start; 52 53 sleep_start = schedstat_val(stats->sleep_start); 54 block_start = schedstat_val(stats->block_start); 55 56 if (sleep_start) { 57 u64 delta = rq_clock(rq) - sleep_start; 58 59 if ((s64)delta < 0) 60 delta = 0; 61 62 if (unlikely(delta > schedstat_val(stats->sleep_max))) 63 __schedstat_set(stats->sleep_max, delta); 64 65 __schedstat_set(stats->sleep_start, 0); 66 __schedstat_add(stats->sum_sleep_runtime, delta); 67 68 if (p) { 69 account_scheduler_latency(p, delta >> 10, 1); 70 trace_sched_stat_sleep(p, delta); 71 } 72 } 73 74 if (block_start) { 75 u64 delta = rq_clock(rq) - block_start; 76 77 if ((s64)delta < 0) 78 delta = 0; 79 80 if (unlikely(delta > schedstat_val(stats->block_max))) 81 __schedstat_set(stats->block_max, delta); 82 83 __schedstat_set(stats->block_start, 0); 84 __schedstat_add(stats->sum_sleep_runtime, delta); 85 __schedstat_add(stats->sum_block_runtime, delta); 86 87 if (p) { 88 if (p->in_iowait) { 89 __schedstat_add(stats->iowait_sum, delta); 90 __schedstat_inc(stats->iowait_count); 91 trace_sched_stat_iowait(p, delta); 92 } 93 94 trace_sched_stat_blocked(p, delta); 95 96 account_scheduler_latency(p, delta >> 10, 0); 97 } 98 } 99 } 100 101 /* 102 * Current schedstat API version. 103 * 104 * Bump this up when changing the output format or the meaning of an existing 105 * format, so that tools can adapt (or abort) 106 */ 107 #define SCHEDSTAT_VERSION 17 108 109 static int show_schedstat(struct seq_file *seq, void *v) 110 { 111 int cpu; 112 113 if (v == (void *)1) { 114 seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION); 115 seq_printf(seq, "timestamp %lu\n", jiffies); 116 } else { 117 struct rq *rq; 118 struct sched_domain *sd; 119 int dcount = 0; 120 cpu = (unsigned long)(v - 2); 121 rq = cpu_rq(cpu); 122 123 /* runqueue-specific stats */ 124 seq_printf(seq, 125 "cpu%d %u 0 %u %u %u %u %llu %llu %lu", 126 cpu, rq->yld_count, 127 rq->sched_count, rq->sched_goidle, 128 rq->ttwu_count, rq->ttwu_local, 129 rq->rq_cpu_time, 130 rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount); 131 132 seq_printf(seq, "\n"); 133 134 /* domain-specific stats */ 135 rcu_read_lock(); 136 for_each_domain(cpu, sd) { 137 enum cpu_idle_type itype; 138 139 seq_printf(seq, "domain%d %s %*pb", dcount++, sd->name, 140 cpumask_pr_args(sched_domain_span(sd))); 141 for (itype = 0; itype < CPU_MAX_IDLE_TYPES; itype++) { 142 seq_printf(seq, " %u %u %u %u %u %u %u %u %u %u %u", 143 sd->lb_count[itype], 144 sd->lb_balanced[itype], 145 sd->lb_failed[itype], 146 sd->lb_imbalance_load[itype], 147 sd->lb_imbalance_util[itype], 148 sd->lb_imbalance_task[itype], 149 sd->lb_imbalance_misfit[itype], 150 sd->lb_gained[itype], 151 sd->lb_hot_gained[itype], 152 sd->lb_nobusyq[itype], 153 sd->lb_nobusyg[itype]); 154 } 155 seq_printf(seq, 156 " %u %u %u %u %u %u %u %u %u %u %u %u\n", 157 sd->alb_count, sd->alb_failed, sd->alb_pushed, 158 sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed, 159 sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed, 160 sd->ttwu_wake_remote, sd->ttwu_move_affine, 161 sd->ttwu_move_balance); 162 } 163 rcu_read_unlock(); 164 } 165 return 0; 166 } 167 168 /* 169 * This iterator needs some explanation. 170 * It returns 1 for the header position. 171 * This means 2 is cpu 0. 172 * In a hotplugged system some CPUs, including cpu 0, may be missing so we have 173 * to use cpumask_* to iterate over the CPUs. 174 */ 175 static void *schedstat_start(struct seq_file *file, loff_t *offset) 176 { 177 unsigned long n = *offset; 178 179 if (n == 0) 180 return (void *) 1; 181 182 n--; 183 184 if (n > 0) 185 n = cpumask_next(n - 1, cpu_online_mask); 186 else 187 n = cpumask_first(cpu_online_mask); 188 189 *offset = n + 1; 190 191 if (n < nr_cpu_ids) 192 return (void *)(unsigned long)(n + 2); 193 194 return NULL; 195 } 196 197 static void *schedstat_next(struct seq_file *file, void *data, loff_t *offset) 198 { 199 (*offset)++; 200 201 return schedstat_start(file, offset); 202 } 203 204 static void schedstat_stop(struct seq_file *file, void *data) 205 { 206 } 207 208 static const struct seq_operations schedstat_sops = { 209 .start = schedstat_start, 210 .next = schedstat_next, 211 .stop = schedstat_stop, 212 .show = show_schedstat, 213 }; 214 215 static int __init proc_schedstat_init(void) 216 { 217 proc_create_seq("schedstat", 0, NULL, &schedstat_sops); 218 return 0; 219 } 220 subsys_initcall(proc_schedstat_init); 221