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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1
2#ifdef CONFIG_SCHEDSTATS
3/*
4 * bump this up when changing the output format or the meaning of an existing
5 * format, so that tools can adapt (or abort)
6 */
7#define SCHEDSTAT_VERSION 14
8
9static int show_schedstat(struct seq_file *seq, void *v)
10{
11 int cpu;
12
13 seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
14 seq_printf(seq, "timestamp %lu\n", jiffies);
15 for_each_online_cpu(cpu) {
16 struct rq *rq = cpu_rq(cpu);
17#ifdef CONFIG_SMP
18 struct sched_domain *sd;
19 int dcount = 0;
20#endif
21
22 /* runqueue-specific stats */
23 seq_printf(seq,
24 "cpu%d %u %u %u %u %u %u %u %u %u %llu %llu %lu",
25 cpu, rq->yld_both_empty,
26 rq->yld_act_empty, rq->yld_exp_empty, rq->yld_count,
27 rq->sched_switch, rq->sched_count, rq->sched_goidle,
28 rq->ttwu_count, rq->ttwu_local,
29 rq->rq_sched_info.cpu_time,
30 rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);
31
32 seq_printf(seq, "\n");
33
34#ifdef CONFIG_SMP
35 /* domain-specific stats */
36 preempt_disable();
37 for_each_domain(cpu, sd) {
38 enum cpu_idle_type itype;
39 char mask_str[NR_CPUS];
40
41 cpumask_scnprintf(mask_str, NR_CPUS, sd->span);
42 seq_printf(seq, "domain%d %s", dcount++, mask_str);
43 for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES;
44 itype++) {
45 seq_printf(seq, " %u %u %u %u %u %u %u %u",
46 sd->lb_count[itype],
47 sd->lb_balanced[itype],
48 sd->lb_failed[itype],
49 sd->lb_imbalance[itype],
50 sd->lb_gained[itype],
51 sd->lb_hot_gained[itype],
52 sd->lb_nobusyq[itype],
53 sd->lb_nobusyg[itype]);
54 }
55 seq_printf(seq,
56 " %u %u %u %u %u %u %u %u %u %u %u %u\n",
57 sd->alb_count, sd->alb_failed, sd->alb_pushed,
58 sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,
59 sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
60 sd->ttwu_wake_remote, sd->ttwu_move_affine,
61 sd->ttwu_move_balance);
62 }
63 preempt_enable();
64#endif
65 }
66 return 0;
67}
68
69static int schedstat_open(struct inode *inode, struct file *file)
70{
71 unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32);
72 char *buf = kmalloc(size, GFP_KERNEL);
73 struct seq_file *m;
74 int res;
75
76 if (!buf)
77 return -ENOMEM;
78 res = single_open(file, show_schedstat, NULL);
79 if (!res) {
80 m = file->private_data;
81 m->buf = buf;
82 m->size = size;
83 } else
84 kfree(buf);
85 return res;
86}
87
88const struct file_operations proc_schedstat_operations = {
89 .open = schedstat_open,
90 .read = seq_read,
91 .llseek = seq_lseek,
92 .release = single_release,
93};
94
95/*
96 * Expects runqueue lock to be held for atomicity of update
97 */
98static inline void
99rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
100{
101 if (rq) {
102 rq->rq_sched_info.run_delay += delta;
103 rq->rq_sched_info.pcount++;
104 }
105}
106
107/*
108 * Expects runqueue lock to be held for atomicity of update
109 */
110static inline void
111rq_sched_info_depart(struct rq *rq, unsigned long long delta)
112{
113 if (rq)
114 rq->rq_sched_info.cpu_time += delta;
115}
116# define schedstat_inc(rq, field) do { (rq)->field++; } while (0)
117# define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0)
118# define schedstat_set(var, val) do { var = (val); } while (0)
119#else /* !CONFIG_SCHEDSTATS */
120static inline void
121rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
122{}
123static inline void
124rq_sched_info_depart(struct rq *rq, unsigned long long delta)
125{}
126# define schedstat_inc(rq, field) do { } while (0)
127# define schedstat_add(rq, field, amt) do { } while (0)
128# define schedstat_set(var, val) do { } while (0)
129#endif
130
131#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
132/*
133 * Called when a process is dequeued from the active array and given
134 * the cpu. We should note that with the exception of interactive
135 * tasks, the expired queue will become the active queue after the active
136 * queue is empty, without explicitly dequeuing and requeuing tasks in the
137 * expired queue. (Interactive tasks may be requeued directly to the
138 * active queue, thus delaying tasks in the expired queue from running;
139 * see scheduler_tick()).
140 *
141 * This function is only called from sched_info_arrive(), rather than
142 * dequeue_task(). Even though a task may be queued and dequeued multiple
143 * times as it is shuffled about, we're really interested in knowing how
144 * long it was from the *first* time it was queued to the time that it
145 * finally hit a cpu.
146 */
147static inline void sched_info_dequeued(struct task_struct *t)
148{
149 t->sched_info.last_queued = 0;
150}
151
152/*
153 * Called when a task finally hits the cpu. We can now calculate how
154 * long it was waiting to run. We also note when it began so that we
155 * can keep stats on how long its timeslice is.
156 */
157static void sched_info_arrive(struct task_struct *t)
158{
159 unsigned long long now = task_rq(t)->clock, delta = 0;
160
161 if (t->sched_info.last_queued)
162 delta = now - t->sched_info.last_queued;
163 sched_info_dequeued(t);
164 t->sched_info.run_delay += delta;
165 t->sched_info.last_arrival = now;
166 t->sched_info.pcount++;
167
168 rq_sched_info_arrive(task_rq(t), delta);
169}
170
171/*
172 * Called when a process is queued into either the active or expired
173 * array. The time is noted and later used to determine how long we
174 * had to wait for us to reach the cpu. Since the expired queue will
175 * become the active queue after active queue is empty, without dequeuing
176 * and requeuing any tasks, we are interested in queuing to either. It
177 * is unusual but not impossible for tasks to be dequeued and immediately
178 * requeued in the same or another array: this can happen in sched_yield(),
179 * set_user_nice(), and even load_balance() as it moves tasks from runqueue
180 * to runqueue.
181 *
182 * This function is only called from enqueue_task(), but also only updates
183 * the timestamp if it is already not set. It's assumed that
184 * sched_info_dequeued() will clear that stamp when appropriate.
185 */
186static inline void sched_info_queued(struct task_struct *t)
187{
188 if (unlikely(sched_info_on()))
189 if (!t->sched_info.last_queued)
190 t->sched_info.last_queued = task_rq(t)->clock;
191}
192
193/*
194 * Called when a process ceases being the active-running process, either
195 * voluntarily or involuntarily. Now we can calculate how long we ran.
196 */
197static inline void sched_info_depart(struct task_struct *t)
198{
199 unsigned long long delta = task_rq(t)->clock -
200 t->sched_info.last_arrival;
201
202 t->sched_info.cpu_time += delta;
203 rq_sched_info_depart(task_rq(t), delta);
204}
205
206/*
207 * Called when tasks are switched involuntarily due, typically, to expiring
208 * their time slice. (This may also be called when switching to or from
209 * the idle task.) We are only called when prev != next.
210 */
211static inline void
212__sched_info_switch(struct task_struct *prev, struct task_struct *next)
213{
214 struct rq *rq = task_rq(prev);
215
216 /*
217 * prev now departs the cpu. It's not interesting to record
218 * stats about how efficient we were at scheduling the idle
219 * process, however.
220 */
221 if (prev != rq->idle)
222 sched_info_depart(prev);
223
224 if (next != rq->idle)
225 sched_info_arrive(next);
226}
227static inline void
228sched_info_switch(struct task_struct *prev, struct task_struct *next)
229{
230 if (unlikely(sched_info_on()))
231 __sched_info_switch(prev, next);
232}
233#else
234#define sched_info_queued(t) do { } while (0)
235#define sched_info_switch(t, next) do { } while (0)
236#endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */
237