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 /* 97 * Blocking time is in units of nanosecs, so shift by 98 * 20 to get a milliseconds-range estimation of the 99 * amount of time that the task spent sleeping: 100 */ 101 if (unlikely(prof_on == SLEEP_PROFILING)) { 102 profile_hits(SLEEP_PROFILING, 103 (void *)get_wchan(p), 104 delta >> 20); 105 } 106 account_scheduler_latency(p, delta >> 10, 0); 107 } 108 } 109 } 110 111 /* 112 * Current schedstat API version. 113 * 114 * Bump this up when changing the output format or the meaning of an existing 115 * format, so that tools can adapt (or abort) 116 */ 117 #define SCHEDSTAT_VERSION 15 118 119 static int show_schedstat(struct seq_file *seq, void *v) 120 { 121 int cpu; 122 123 if (v == (void *)1) { 124 seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION); 125 seq_printf(seq, "timestamp %lu\n", jiffies); 126 } else { 127 struct rq *rq; 128 #ifdef CONFIG_SMP 129 struct sched_domain *sd; 130 int dcount = 0; 131 #endif 132 cpu = (unsigned long)(v - 2); 133 rq = cpu_rq(cpu); 134 135 /* runqueue-specific stats */ 136 seq_printf(seq, 137 "cpu%d %u 0 %u %u %u %u %llu %llu %lu", 138 cpu, rq->yld_count, 139 rq->sched_count, rq->sched_goidle, 140 rq->ttwu_count, rq->ttwu_local, 141 rq->rq_cpu_time, 142 rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount); 143 144 seq_printf(seq, "\n"); 145 146 #ifdef CONFIG_SMP 147 /* domain-specific stats */ 148 rcu_read_lock(); 149 for_each_domain(cpu, sd) { 150 enum cpu_idle_type itype; 151 152 seq_printf(seq, "domain%d %*pb", dcount++, 153 cpumask_pr_args(sched_domain_span(sd))); 154 for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES; 155 itype++) { 156 seq_printf(seq, " %u %u %u %u %u %u %u %u", 157 sd->lb_count[itype], 158 sd->lb_balanced[itype], 159 sd->lb_failed[itype], 160 sd->lb_imbalance[itype], 161 sd->lb_gained[itype], 162 sd->lb_hot_gained[itype], 163 sd->lb_nobusyq[itype], 164 sd->lb_nobusyg[itype]); 165 } 166 seq_printf(seq, 167 " %u %u %u %u %u %u %u %u %u %u %u %u\n", 168 sd->alb_count, sd->alb_failed, sd->alb_pushed, 169 sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed, 170 sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed, 171 sd->ttwu_wake_remote, sd->ttwu_move_affine, 172 sd->ttwu_move_balance); 173 } 174 rcu_read_unlock(); 175 #endif 176 } 177 return 0; 178 } 179 180 /* 181 * This iterator needs some explanation. 182 * It returns 1 for the header position. 183 * This means 2 is cpu 0. 184 * In a hotplugged system some CPUs, including cpu 0, may be missing so we have 185 * to use cpumask_* to iterate over the CPUs. 186 */ 187 static void *schedstat_start(struct seq_file *file, loff_t *offset) 188 { 189 unsigned long n = *offset; 190 191 if (n == 0) 192 return (void *) 1; 193 194 n--; 195 196 if (n > 0) 197 n = cpumask_next(n - 1, cpu_online_mask); 198 else 199 n = cpumask_first(cpu_online_mask); 200 201 *offset = n + 1; 202 203 if (n < nr_cpu_ids) 204 return (void *)(unsigned long)(n + 2); 205 206 return NULL; 207 } 208 209 static void *schedstat_next(struct seq_file *file, void *data, loff_t *offset) 210 { 211 (*offset)++; 212 213 return schedstat_start(file, offset); 214 } 215 216 static void schedstat_stop(struct seq_file *file, void *data) 217 { 218 } 219 220 static const struct seq_operations schedstat_sops = { 221 .start = schedstat_start, 222 .next = schedstat_next, 223 .stop = schedstat_stop, 224 .show = show_schedstat, 225 }; 226 227 static int __init proc_schedstat_init(void) 228 { 229 proc_create_seq("schedstat", 0, NULL, &schedstat_sops); 230 return 0; 231 } 232 subsys_initcall(proc_schedstat_init); 233