xref: /linux/kernel/sched/stats.c (revision f884ab15afdc5514e88105c92a4e2e1e6539869a)
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);
146