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
show_schedstat(struct seq_file * seq,void * v)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 %u %u %u %llu %llu %lu",
30 cpu, rq->yld_both_empty,
31 rq->yld_act_empty, rq->yld_exp_empty, rq->yld_count,
32 rq->sched_switch, rq->sched_count, rq->sched_goidle,
33 rq->ttwu_count, rq->ttwu_local,
34 rq->rq_cpu_time,
35 rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);
36
37 seq_printf(seq, "\n");
38
39 #ifdef CONFIG_SMP
40 /* domain-specific stats */
41 preempt_disable();
42 for_each_domain(cpu, sd) {
43 enum cpu_idle_type itype;
44
45 cpumask_scnprintf(mask_str, mask_len,
46 sched_domain_span(sd));
47 seq_printf(seq, "domain%d %s", dcount++, mask_str);
48 for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES;
49 itype++) {
50 seq_printf(seq, " %u %u %u %u %u %u %u %u",
51 sd->lb_count[itype],
52 sd->lb_balanced[itype],
53 sd->lb_failed[itype],
54 sd->lb_imbalance[itype],
55 sd->lb_gained[itype],
56 sd->lb_hot_gained[itype],
57 sd->lb_nobusyq[itype],
58 sd->lb_nobusyg[itype]);
59 }
60 seq_printf(seq,
61 " %u %u %u %u %u %u %u %u %u %u %u %u\n",
62 sd->alb_count, sd->alb_failed, sd->alb_pushed,
63 sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,
64 sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
65 sd->ttwu_wake_remote, sd->ttwu_move_affine,
66 sd->ttwu_move_balance);
67 }
68 preempt_enable();
69 #endif
70 }
71 kfree(mask_str);
72 return 0;
73 }
74
schedstat_open(struct inode * inode,struct file * file)75 static int schedstat_open(struct inode *inode, struct file *file)
76 {
77 unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32);
78 char *buf = kmalloc(size, GFP_KERNEL);
79 struct seq_file *m;
80 int res;
81
82 if (!buf)
83 return -ENOMEM;
84 res = single_open(file, show_schedstat, NULL);
85 if (!res) {
86 m = file->private_data;
87 m->buf = buf;
88 m->size = size;
89 } else
90 kfree(buf);
91 return res;
92 }
93
94 static const struct file_operations proc_schedstat_operations = {
95 .open = schedstat_open,
96 .read = seq_read,
97 .llseek = seq_lseek,
98 .release = single_release,
99 };
100
proc_schedstat_init(void)101 static int __init proc_schedstat_init(void)
102 {
103 proc_create("schedstat", 0, NULL, &proc_schedstat_operations);
104 return 0;
105 }
106 module_init(proc_schedstat_init);
107
108 /*
109 * Expects runqueue lock to be held for atomicity of update
110 */
111 static inline void
rq_sched_info_arrive(struct rq * rq,unsigned long long delta)112 rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
113 {
114 if (rq) {
115 rq->rq_sched_info.run_delay += delta;
116 rq->rq_sched_info.pcount++;
117 }
118 }
119
120 /*
121 * Expects runqueue lock to be held for atomicity of update
122 */
123 static inline void
rq_sched_info_depart(struct rq * rq,unsigned long long delta)124 rq_sched_info_depart(struct rq *rq, unsigned long long delta)
125 {
126 if (rq)
127 rq->rq_cpu_time += delta;
128 }
129
130 static inline void
rq_sched_info_dequeued(struct rq * rq,unsigned long long delta)131 rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
132 {
133 if (rq)
134 rq->rq_sched_info.run_delay += delta;
135 }
136 # define schedstat_inc(rq, field) do { (rq)->field++; } while (0)
137 # define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0)
138 # define schedstat_set(var, val) do { var = (val); } while (0)
139 #else /* !CONFIG_SCHEDSTATS */
140 static inline void
rq_sched_info_arrive(struct rq * rq,unsigned long long delta)141 rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
142 {}
143 static inline void
rq_sched_info_dequeued(struct rq * rq,unsigned long long delta)144 rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
145 {}
146 static inline void
rq_sched_info_depart(struct rq * rq,unsigned long long delta)147 rq_sched_info_depart(struct rq *rq, unsigned long long delta)
148 {}
149 # define schedstat_inc(rq, field) do { } while (0)
150 # define schedstat_add(rq, field, amt) do { } while (0)
151 # define schedstat_set(var, val) do { } while (0)
152 #endif
153
154 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
sched_info_reset_dequeued(struct task_struct * t)155 static inline void sched_info_reset_dequeued(struct task_struct *t)
156 {
157 t->sched_info.last_queued = 0;
158 }
159
160 /*
161 * Called when a process is dequeued from the active array and given
162 * the cpu. We should note that with the exception of interactive
163 * tasks, the expired queue will become the active queue after the active
164 * queue is empty, without explicitly dequeuing and requeuing tasks in the
165 * expired queue. (Interactive tasks may be requeued directly to the
166 * active queue, thus delaying tasks in the expired queue from running;
167 * see scheduler_tick()).
168 *
169 * Though we are interested in knowing how long it was from the *first* time a
170 * task was queued to the time that it finally hit a cpu, we call this routine
171 * from dequeue_task() to account for possible rq->clock skew across cpus. The
172 * delta taken on each cpu would annul the skew.
173 */
sched_info_dequeued(struct task_struct * t)174 static inline void sched_info_dequeued(struct task_struct *t)
175 {
176 unsigned long long now = task_rq(t)->clock, delta = 0;
177
178 if (unlikely(sched_info_on()))
179 if (t->sched_info.last_queued)
180 delta = now - t->sched_info.last_queued;
181 sched_info_reset_dequeued(t);
182 t->sched_info.run_delay += delta;
183
184 rq_sched_info_dequeued(task_rq(t), delta);
185 }
186
187 /*
188 * Called when a task finally hits the cpu. We can now calculate how
189 * long it was waiting to run. We also note when it began so that we
190 * can keep stats on how long its timeslice is.
191 */
sched_info_arrive(struct task_struct * t)192 static void sched_info_arrive(struct task_struct *t)
193 {
194 unsigned long long now = task_rq(t)->clock, delta = 0;
195
196 if (t->sched_info.last_queued)
197 delta = now - t->sched_info.last_queued;
198 sched_info_reset_dequeued(t);
199 t->sched_info.run_delay += delta;
200 t->sched_info.last_arrival = now;
201 t->sched_info.pcount++;
202
203 rq_sched_info_arrive(task_rq(t), delta);
204 }
205
206 /*
207 * Called when a process is queued into either the active or expired
208 * array. The time is noted and later used to determine how long we
209 * had to wait for us to reach the cpu. Since the expired queue will
210 * become the active queue after active queue is empty, without dequeuing
211 * and requeuing any tasks, we are interested in queuing to either. It
212 * is unusual but not impossible for tasks to be dequeued and immediately
213 * requeued in the same or another array: this can happen in sched_yield(),
214 * set_user_nice(), and even load_balance() as it moves tasks from runqueue
215 * to runqueue.
216 *
217 * This function is only called from enqueue_task(), but also only updates
218 * the timestamp if it is already not set. It's assumed that
219 * sched_info_dequeued() will clear that stamp when appropriate.
220 */
sched_info_queued(struct task_struct * t)221 static inline void sched_info_queued(struct task_struct *t)
222 {
223 if (unlikely(sched_info_on()))
224 if (!t->sched_info.last_queued)
225 t->sched_info.last_queued = task_rq(t)->clock;
226 }
227
228 /*
229 * Called when a process ceases being the active-running process, either
230 * voluntarily or involuntarily. Now we can calculate how long we ran.
231 * Also, if the process is still in the TASK_RUNNING state, call
232 * sched_info_queued() to mark that it has now again started waiting on
233 * the runqueue.
234 */
sched_info_depart(struct task_struct * t)235 static inline void sched_info_depart(struct task_struct *t)
236 {
237 unsigned long long delta = task_rq(t)->clock -
238 t->sched_info.last_arrival;
239
240 rq_sched_info_depart(task_rq(t), delta);
241
242 if (t->state == TASK_RUNNING)
243 sched_info_queued(t);
244 }
245
246 /*
247 * Called when tasks are switched involuntarily due, typically, to expiring
248 * their time slice. (This may also be called when switching to or from
249 * the idle task.) We are only called when prev != next.
250 */
251 static inline void
__sched_info_switch(struct task_struct * prev,struct task_struct * next)252 __sched_info_switch(struct task_struct *prev, struct task_struct *next)
253 {
254 struct rq *rq = task_rq(prev);
255
256 /*
257 * prev now departs the cpu. It's not interesting to record
258 * stats about how efficient we were at scheduling the idle
259 * process, however.
260 */
261 if (prev != rq->idle)
262 sched_info_depart(prev);
263
264 if (next != rq->idle)
265 sched_info_arrive(next);
266 }
267 static inline void
sched_info_switch(struct task_struct * prev,struct task_struct * next)268 sched_info_switch(struct task_struct *prev, struct task_struct *next)
269 {
270 if (unlikely(sched_info_on()))
271 __sched_info_switch(prev, next);
272 }
273 #else
274 #define sched_info_queued(t) do { } while (0)
275 #define sched_info_reset_dequeued(t) do { } while (0)
276 #define sched_info_dequeued(t) do { } while (0)
277 #define sched_info_switch(t, next) do { } while (0)
278 #endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */
279
280 /*
281 * The following are functions that support scheduler-internal time accounting.
282 * These functions are generally called at the timer tick. None of this depends
283 * on CONFIG_SCHEDSTATS.
284 */
285
286 /**
287 * account_group_user_time - Maintain utime for a thread group.
288 *
289 * @tsk: Pointer to task structure.
290 * @cputime: Time value by which to increment the utime field of the
291 * thread_group_cputime structure.
292 *
293 * If thread group time is being maintained, get the structure for the
294 * running CPU and update the utime field there.
295 */
account_group_user_time(struct task_struct * tsk,cputime_t cputime)296 static inline void account_group_user_time(struct task_struct *tsk,
297 cputime_t cputime)
298 {
299 struct thread_group_cputimer *cputimer;
300
301 /* tsk == current, ensure it is safe to use ->signal */
302 if (unlikely(tsk->exit_state))
303 return;
304
305 cputimer = &tsk->signal->cputimer;
306
307 if (!cputimer->running)
308 return;
309
310 spin_lock(&cputimer->lock);
311 cputimer->cputime.utime =
312 cputime_add(cputimer->cputime.utime, cputime);
313 spin_unlock(&cputimer->lock);
314 }
315
316 /**
317 * account_group_system_time - Maintain stime for a thread group.
318 *
319 * @tsk: Pointer to task structure.
320 * @cputime: Time value by which to increment the stime field of the
321 * thread_group_cputime structure.
322 *
323 * If thread group time is being maintained, get the structure for the
324 * running CPU and update the stime field there.
325 */
account_group_system_time(struct task_struct * tsk,cputime_t cputime)326 static inline void account_group_system_time(struct task_struct *tsk,
327 cputime_t cputime)
328 {
329 struct thread_group_cputimer *cputimer;
330
331 /* tsk == current, ensure it is safe to use ->signal */
332 if (unlikely(tsk->exit_state))
333 return;
334
335 cputimer = &tsk->signal->cputimer;
336
337 if (!cputimer->running)
338 return;
339
340 spin_lock(&cputimer->lock);
341 cputimer->cputime.stime =
342 cputime_add(cputimer->cputime.stime, cputime);
343 spin_unlock(&cputimer->lock);
344 }
345
346 /**
347 * account_group_exec_runtime - Maintain exec runtime for a thread group.
348 *
349 * @tsk: Pointer to task structure.
350 * @ns: Time value by which to increment the sum_exec_runtime field
351 * of the thread_group_cputime structure.
352 *
353 * If thread group time is being maintained, get the structure for the
354 * running CPU and update the sum_exec_runtime field there.
355 */
account_group_exec_runtime(struct task_struct * tsk,unsigned long long ns)356 static inline void account_group_exec_runtime(struct task_struct *tsk,
357 unsigned long long ns)
358 {
359 struct thread_group_cputimer *cputimer;
360 struct signal_struct *sig;
361
362 sig = tsk->signal;
363 /* see __exit_signal()->task_rq_unlock_wait() */
364 barrier();
365 if (unlikely(!sig))
366 return;
367
368 cputimer = &sig->cputimer;
369
370 if (!cputimer->running)
371 return;
372
373 spin_lock(&cputimer->lock);
374 cputimer->cputime.sum_exec_runtime += ns;
375 spin_unlock(&cputimer->lock);
376 }
377