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 15
8
9 static int show_schedstat(struct seq_file *seq, void *v)
10 {
11 int cpu;
12 int mask_len = DIV_ROUND_UP(NR_CPUS, 32) * 9;
13 char *mask_str = kmalloc(mask_len, GFP_KERNEL);
14
15 if (mask_str == NULL)
16 return -ENOMEM;
17
18 seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
19 seq_printf(seq, "timestamp %lu\n", jiffies);
20 for_each_online_cpu(cpu) {
21 struct rq *rq = cpu_rq(cpu);
22 #ifdef CONFIG_SMP
23 struct sched_domain *sd;
24 int dcount = 0;
25 #endif
26
27 /* runqueue-specific stats */
28 seq_printf(seq,
29 "cpu%d %u %u %u %u %u %u %llu %llu %lu",
30 cpu, rq->yld_count,
31 rq->sched_switch, rq->sched_count, rq->sched_goidle,
32 rq->ttwu_count, rq->ttwu_local,
33 rq->rq_cpu_time,
34 rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);
35
36 seq_printf(seq, "\n");
37
38 #ifdef CONFIG_SMP
39 /* domain-specific stats */
40 preempt_disable();
41 for_each_domain(cpu, sd) {
42 enum cpu_idle_type itype;
43
44 cpumask_scnprintf(mask_str, mask_len,
45 sched_domain_span(sd));
46 seq_printf(seq, "domain%d %s", dcount++, mask_str);
47 for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES;
48 itype++) {
49 seq_printf(seq, " %u %u %u %u %u %u %u %u",
50 sd->lb_count[itype],
51 sd->lb_balanced[itype],
52 sd->lb_failed[itype],
53 sd->lb_imbalance[itype],
54 sd->lb_gained[itype],
55 sd->lb_hot_gained[itype],
56 sd->lb_nobusyq[itype],
57 sd->lb_nobusyg[itype]);
58 }
59 seq_printf(seq,
60 " %u %u %u %u %u %u %u %u %u %u %u %u\n",
61 sd->alb_count, sd->alb_failed, sd->alb_pushed,
62 sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,
63 sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
64 sd->ttwu_wake_remote, sd->ttwu_move_affine,
65 sd->ttwu_move_balance);
66 }
67 preempt_enable();
68 #endif
69 }
70 kfree(mask_str);
71 return 0;
72 }
73
74 static int schedstat_open(struct inode *inode, struct file *file)
75 {
76 unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32);
77 char *buf = kmalloc(size, GFP_KERNEL);
78 struct seq_file *m;
79 int res;
80
81 if (!buf)
82 return -ENOMEM;
83 res = single_open(file, show_schedstat, NULL);
84 if (!res) {
85 m = file->private_data;
86 m->buf = buf;
87 m->size = size;
88 } else
89 kfree(buf);
90 return res;
91 }
92
93 static const struct file_operations proc_schedstat_operations = {
94 .open = schedstat_open,
95 .read = seq_read,
96 .llseek = seq_lseek,
97 .release = single_release,
98 };
99
100 static int __init proc_schedstat_init(void)
101 {
102 proc_create("schedstat", 0, NULL, &proc_schedstat_operations);
103 return 0;
104 }
105 module_init(proc_schedstat_init);
106
107 /*
108 * Expects runqueue lock to be held for atomicity of update
109 */
110 static inline void
111 rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
112 {
113 if (rq) {
114 rq->rq_sched_info.run_delay += delta;
115 rq->rq_sched_info.pcount++;
116 }
117 }
118
119 /*
120 * Expects runqueue lock to be held for atomicity of update
121 */
122 static inline void
123 rq_sched_info_depart(struct rq *rq, unsigned long long delta)
124 {
125 if (rq)
126 rq->rq_cpu_time += delta;
127 }
128
129 static inline void
130 rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
131 {
132 if (rq)
133 rq->rq_sched_info.run_delay += delta;
134 }
135 # define schedstat_inc(rq, field) do { (rq)->field++; } while (0)
136 # define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0)
137 # define schedstat_set(var, val) do { var = (val); } while (0)
138 #else /* !CONFIG_SCHEDSTATS */
139 static inline void
140 rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
141 {}
142 static inline void
143 rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
144 {}
145 static inline void
146 rq_sched_info_depart(struct rq *rq, unsigned long long delta)
147 {}
148 # define schedstat_inc(rq, field) do { } while (0)
149 # define schedstat_add(rq, field, amt) do { } while (0)
150 # define schedstat_set(var, val) do { } while (0)
151 #endif
152
153 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
154 static inline void sched_info_reset_dequeued(struct task_struct *t)
155 {
156 t->sched_info.last_queued = 0;
157 }
158
159 /*
160 * Called when a process is dequeued from the active array and given
161 * the cpu. We should note that with the exception of interactive
162 * tasks, the expired queue will become the active queue after the active
163 * queue is empty, without explicitly dequeuing and requeuing tasks in the
164 * expired queue. (Interactive tasks may be requeued directly to the
165 * active queue, thus delaying tasks in the expired queue from running;
166 * see scheduler_tick()).
167 *
168 * Though we are interested in knowing how long it was from the *first* time a
169 * task was queued to the time that it finally hit a cpu, we call this routine
170 * from dequeue_task() to account for possible rq->clock skew across cpus. The
171 * delta taken on each cpu would annul the skew.
172 */
173 static inline void sched_info_dequeued(struct task_struct *t)
174 {
175 unsigned long long now = task_rq(t)->clock, delta = 0;
176
177 if (unlikely(sched_info_on()))
178 if (t->sched_info.last_queued)
179 delta = now - t->sched_info.last_queued;
180 sched_info_reset_dequeued(t);
181 t->sched_info.run_delay += delta;
182
183 rq_sched_info_dequeued(task_rq(t), delta);
184 }
185
186 /*
187 * Called when a task finally hits the cpu. We can now calculate how
188 * long it was waiting to run. We also note when it began so that we
189 * can keep stats on how long its timeslice is.
190 */
191 static void sched_info_arrive(struct task_struct *t)
192 {
193 unsigned long long now = task_rq(t)->clock, delta = 0;
194
195 if (t->sched_info.last_queued)
196 delta = now - t->sched_info.last_queued;
197 sched_info_reset_dequeued(t);
198 t->sched_info.run_delay += delta;
199 t->sched_info.last_arrival = now;
200 t->sched_info.pcount++;
201
202 rq_sched_info_arrive(task_rq(t), delta);
203 }
204
205 /*
206 * Called when a process is queued into either the active or expired
207 * array. The time is noted and later used to determine how long we
208 * had to wait for us to reach the cpu. Since the expired queue will
209 * become the active queue after active queue is empty, without dequeuing
210 * and requeuing any tasks, we are interested in queuing to either. It
211 * is unusual but not impossible for tasks to be dequeued and immediately
212 * requeued in the same or another array: this can happen in sched_yield(),
213 * set_user_nice(), and even load_balance() as it moves tasks from runqueue
214 * to runqueue.
215 *
216 * This function is only called from enqueue_task(), but also only updates
217 * the timestamp if it is already not set. It's assumed that
218 * sched_info_dequeued() will clear that stamp when appropriate.
219 */
220 static inline void sched_info_queued(struct task_struct *t)
221 {
222 if (unlikely(sched_info_on()))
223 if (!t->sched_info.last_queued)
224 t->sched_info.last_queued = task_rq(t)->clock;
225 }
226
227 /*
228 * Called when a process ceases being the active-running process, either
229 * voluntarily or involuntarily. Now we can calculate how long we ran.
230 * Also, if the process is still in the TASK_RUNNING state, call
231 * sched_info_queued() to mark that it has now again started waiting on
232 * the runqueue.
233 */
234 static inline void sched_info_depart(struct task_struct *t)
235 {
236 unsigned long long delta = task_rq(t)->clock -
237 t->sched_info.last_arrival;
238
239 rq_sched_info_depart(task_rq(t), delta);
240
241 if (t->state == TASK_RUNNING)
242 sched_info_queued(t);
243 }
244
245 /*
246 * Called when tasks are switched involuntarily due, typically, to expiring
247 * their time slice. (This may also be called when switching to or from
248 * the idle task.) We are only called when prev != next.
249 */
250 static inline void
251 __sched_info_switch(struct task_struct *prev, struct task_struct *next)
252 {
253 struct rq *rq = task_rq(prev);
254
255 /*
256 * prev now departs the cpu. It's not interesting to record
257 * stats about how efficient we were at scheduling the idle
258 * process, however.
259 */
260 if (prev != rq->idle)
261 sched_info_depart(prev);
262
263 if (next != rq->idle)
264 sched_info_arrive(next);
265 }
266 static inline void
267 sched_info_switch(struct task_struct *prev, struct task_struct *next)
268 {
269 if (unlikely(sched_info_on()))
270 __sched_info_switch(prev, next);
271 }
272 #else
273 #define sched_info_queued(t) do { } while (0)
274 #define sched_info_reset_dequeued(t) do { } while (0)
275 #define sched_info_dequeued(t) do { } while (0)
276 #define sched_info_switch(t, next) do { } while (0)
277 #endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */
278
279 /*
280 * The following are functions that support scheduler-internal time accounting.
281 * These functions are generally called at the timer tick. None of this depends
282 * on CONFIG_SCHEDSTATS.
283 */
284
285 /**
286 * account_group_user_time - Maintain utime for a thread group.
287 *
288 * @tsk: Pointer to task structure.
289 * @cputime: Time value by which to increment the utime field of the
290 * thread_group_cputime structure.
291 *
292 * If thread group time is being maintained, get the structure for the
293 * running CPU and update the utime field there.
294 */
295 static inline void account_group_user_time(struct task_struct *tsk,
296 cputime_t cputime)
297 {
298 struct thread_group_cputimer *cputimer;
299
300 /* tsk == current, ensure it is safe to use ->signal */
301 if (unlikely(tsk->exit_state))
302 return;
303
304 cputimer = &tsk->signal->cputimer;
305
306 if (!cputimer->running)
307 return;
308
309 spin_lock(&cputimer->lock);
310 cputimer->cputime.utime =
311 cputime_add(cputimer->cputime.utime, cputime);
312 spin_unlock(&cputimer->lock);
313 }
314
315 /**
316 * account_group_system_time - Maintain stime for a thread group.
317 *
318 * @tsk: Pointer to task structure.
319 * @cputime: Time value by which to increment the stime field of the
320 * thread_group_cputime structure.
321 *
322 * If thread group time is being maintained, get the structure for the
323 * running CPU and update the stime field there.
324 */
325 static inline void account_group_system_time(struct task_struct *tsk,
326 cputime_t cputime)
327 {
328 struct thread_group_cputimer *cputimer;
329
330 /* tsk == current, ensure it is safe to use ->signal */
331 if (unlikely(tsk->exit_state))
332 return;
333
334 cputimer = &tsk->signal->cputimer;
335
336 if (!cputimer->running)
337 return;
338
339 spin_lock(&cputimer->lock);
340 cputimer->cputime.stime =
341 cputime_add(cputimer->cputime.stime, cputime);
342 spin_unlock(&cputimer->lock);
343 }
344
345 /**
346 * account_group_exec_runtime - Maintain exec runtime for a thread group.
347 *
348 * @tsk: Pointer to task structure.
349 * @ns: Time value by which to increment the sum_exec_runtime field
350 * of the thread_group_cputime structure.
351 *
352 * If thread group time is being maintained, get the structure for the
353 * running CPU and update the sum_exec_runtime field there.
354 */
355 static inline void account_group_exec_runtime(struct task_struct *tsk,
356 unsigned long long ns)
357 {
358 struct thread_group_cputimer *cputimer;
359 struct signal_struct *sig;
360
361 sig = tsk->signal;
362 /* see __exit_signal()->task_rq_unlock_wait() */
363 barrier();
364 if (unlikely(!sig))
365 return;
366
367 cputimer = &sig->cputimer;
368
369 if (!cputimer->running)
370 return;
371
372 spin_lock(&cputimer->lock);
373 cputimer->cputime.sum_exec_runtime += ns;
374 spin_unlock(&cputimer->lock);
375 }
376
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