LXR linux/kernel/sched

   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
 238