kernel/sched_stats.h

   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 }