Revision 7f453c24b95a085fc7bd35d53b33abc4dc5a048b authored by Peter Zijlstra on 21 July 2009, 11:19:40 UTC, committed by Peter Zijlstra on 22 July 2009, 16:05:56 UTC
Anton noted that for inherited counters the counter-id as provided by PERF_SAMPLE_ID isn't mappable to the id found through PERF_RECORD_ID because each inherited counter gets its own id. His suggestion was to always return the parent counter id, since that is the primary counter id as exposed. However, these inherited counters have a unique identifier so that events like PERF_EVENT_PERIOD and PERF_EVENT_THROTTLE can be specific about which counter gets modified, which is important when trying to normalize the sample streams. This patch removes PERF_EVENT_PERIOD in favour of PERF_SAMPLE_PERIOD, which is more useful anyway, since changing periods became a lot more common than initially thought -- rendering PERF_EVENT_PERIOD the less useful solution (also, PERF_SAMPLE_PERIOD reports the more accurate value, since it reports the value used to trigger the overflow, whereas PERF_EVENT_PERIOD simply reports the requested period changed, which might only take effect on the next cycle). This still leaves us PERF_EVENT_THROTTLE to consider, but since that _should_ be a rare occurrence, and linking it to a primary id is the most useful bit to diagnose the problem, we introduce a PERF_SAMPLE_STREAM_ID, for those few cases where the full reconstruction is important. [Does change the ABI a little, but I see no other way out] Suggested-by: Anton Blanchard <anton@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1248095846.15751.8781.camel@twins>
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sched_stats.h
#ifdef CONFIG_SCHEDSTATS
/*
* bump this up when changing the output format or the meaning of an existing
* format, so that tools can adapt (or abort)
*/
#define SCHEDSTAT_VERSION 15
static int show_schedstat(struct seq_file *seq, void *v)
{
int cpu;
int mask_len = DIV_ROUND_UP(NR_CPUS, 32) * 9;
char *mask_str = kmalloc(mask_len, GFP_KERNEL);
if (mask_str == NULL)
return -ENOMEM;
seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
seq_printf(seq, "timestamp %lu\n", jiffies);
for_each_online_cpu(cpu) {
struct rq *rq = cpu_rq(cpu);
#ifdef CONFIG_SMP
struct sched_domain *sd;
int dcount = 0;
#endif
/* runqueue-specific stats */
seq_printf(seq,
"cpu%d %u %u %u %u %u %u %llu %llu %lu",
cpu, rq->yld_count,
rq->sched_switch, rq->sched_count, rq->sched_goidle,
rq->ttwu_count, rq->ttwu_local,
rq->rq_cpu_time,
rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);
seq_printf(seq, "\n");
#ifdef CONFIG_SMP
/* domain-specific stats */
preempt_disable();
for_each_domain(cpu, sd) {
enum cpu_idle_type itype;
cpumask_scnprintf(mask_str, mask_len,
sched_domain_span(sd));
seq_printf(seq, "domain%d %s", dcount++, mask_str);
for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES;
itype++) {
seq_printf(seq, " %u %u %u %u %u %u %u %u",
sd->lb_count[itype],
sd->lb_balanced[itype],
sd->lb_failed[itype],
sd->lb_imbalance[itype],
sd->lb_gained[itype],
sd->lb_hot_gained[itype],
sd->lb_nobusyq[itype],
sd->lb_nobusyg[itype]);
}
seq_printf(seq,
" %u %u %u %u %u %u %u %u %u %u %u %u\n",
sd->alb_count, sd->alb_failed, sd->alb_pushed,
sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,
sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
sd->ttwu_wake_remote, sd->ttwu_move_affine,
sd->ttwu_move_balance);
}
preempt_enable();
#endif
}
kfree(mask_str);
return 0;
}
static int schedstat_open(struct inode *inode, struct file *file)
{
unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32);
char *buf = kmalloc(size, GFP_KERNEL);
struct seq_file *m;
int res;
if (!buf)
return -ENOMEM;
res = single_open(file, show_schedstat, NULL);
if (!res) {
m = file->private_data;
m->buf = buf;
m->size = size;
} else
kfree(buf);
return res;
}
static const struct file_operations proc_schedstat_operations = {
.open = schedstat_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int __init proc_schedstat_init(void)
{
proc_create("schedstat", 0, NULL, &proc_schedstat_operations);
return 0;
}
module_init(proc_schedstat_init);
/*
* Expects runqueue lock to be held for atomicity of update
*/
static inline void
rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
{
if (rq) {
rq->rq_sched_info.run_delay += delta;
rq->rq_sched_info.pcount++;
}
}
/*
* Expects runqueue lock to be held for atomicity of update
*/
static inline void
rq_sched_info_depart(struct rq *rq, unsigned long long delta)
{
if (rq)
rq->rq_cpu_time += delta;
}
static inline void
rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
{
if (rq)
rq->rq_sched_info.run_delay += delta;
}
# define schedstat_inc(rq, field) do { (rq)->field++; } while (0)
# define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0)
# define schedstat_set(var, val) do { var = (val); } while (0)
#else /* !CONFIG_SCHEDSTATS */
static inline void
rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
{}
static inline void
rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
{}
static inline void
rq_sched_info_depart(struct rq *rq, unsigned long long delta)
{}
# define schedstat_inc(rq, field) do { } while (0)
# define schedstat_add(rq, field, amt) do { } while (0)
# define schedstat_set(var, val) do { } while (0)
#endif
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
static inline void sched_info_reset_dequeued(struct task_struct *t)
{
t->sched_info.last_queued = 0;
}
/*
* Called when a process is dequeued from the active array and given
* the cpu. We should note that with the exception of interactive
* tasks, the expired queue will become the active queue after the active
* queue is empty, without explicitly dequeuing and requeuing tasks in the
* expired queue. (Interactive tasks may be requeued directly to the
* active queue, thus delaying tasks in the expired queue from running;
* see scheduler_tick()).
*
* Though we are interested in knowing how long it was from the *first* time a
* task was queued to the time that it finally hit a cpu, we call this routine
* from dequeue_task() to account for possible rq->clock skew across cpus. The
* delta taken on each cpu would annul the skew.
*/
static inline void sched_info_dequeued(struct task_struct *t)
{
unsigned long long now = task_rq(t)->clock, delta = 0;
if (unlikely(sched_info_on()))
if (t->sched_info.last_queued)
delta = now - t->sched_info.last_queued;
sched_info_reset_dequeued(t);
t->sched_info.run_delay += delta;
rq_sched_info_dequeued(task_rq(t), delta);
}
/*
* Called when a task finally hits the cpu. We can now calculate how
* long it was waiting to run. We also note when it began so that we
* can keep stats on how long its timeslice is.
*/
static void sched_info_arrive(struct task_struct *t)
{
unsigned long long now = task_rq(t)->clock, delta = 0;
if (t->sched_info.last_queued)
delta = now - t->sched_info.last_queued;
sched_info_reset_dequeued(t);
t->sched_info.run_delay += delta;
t->sched_info.last_arrival = now;
t->sched_info.pcount++;
rq_sched_info_arrive(task_rq(t), delta);
}
/*
* Called when a process is queued into either the active or expired
* array. The time is noted and later used to determine how long we
* had to wait for us to reach the cpu. Since the expired queue will
* become the active queue after active queue is empty, without dequeuing
* and requeuing any tasks, we are interested in queuing to either. It
* is unusual but not impossible for tasks to be dequeued and immediately
* requeued in the same or another array: this can happen in sched_yield(),
* set_user_nice(), and even load_balance() as it moves tasks from runqueue
* to runqueue.
*
* This function is only called from enqueue_task(), but also only updates
* the timestamp if it is already not set. It's assumed that
* sched_info_dequeued() will clear that stamp when appropriate.
*/
static inline void sched_info_queued(struct task_struct *t)
{
if (unlikely(sched_info_on()))
if (!t->sched_info.last_queued)
t->sched_info.last_queued = task_rq(t)->clock;
}
/*
* Called when a process ceases being the active-running process, either
* voluntarily or involuntarily. Now we can calculate how long we ran.
* Also, if the process is still in the TASK_RUNNING state, call
* sched_info_queued() to mark that it has now again started waiting on
* the runqueue.
*/
static inline void sched_info_depart(struct task_struct *t)
{
unsigned long long delta = task_rq(t)->clock -
t->sched_info.last_arrival;
rq_sched_info_depart(task_rq(t), delta);
if (t->state == TASK_RUNNING)
sched_info_queued(t);
}
/*
* Called when tasks are switched involuntarily due, typically, to expiring
* their time slice. (This may also be called when switching to or from
* the idle task.) We are only called when prev != next.
*/
static inline void
__sched_info_switch(struct task_struct *prev, struct task_struct *next)
{
struct rq *rq = task_rq(prev);
/*
* prev now departs the cpu. It's not interesting to record
* stats about how efficient we were at scheduling the idle
* process, however.
*/
if (prev != rq->idle)
sched_info_depart(prev);
if (next != rq->idle)
sched_info_arrive(next);
}
static inline void
sched_info_switch(struct task_struct *prev, struct task_struct *next)
{
if (unlikely(sched_info_on()))
__sched_info_switch(prev, next);
}
#else
#define sched_info_queued(t) do { } while (0)
#define sched_info_reset_dequeued(t) do { } while (0)
#define sched_info_dequeued(t) do { } while (0)
#define sched_info_switch(t, next) do { } while (0)
#endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */
/*
* The following are functions that support scheduler-internal time accounting.
* These functions are generally called at the timer tick. None of this depends
* on CONFIG_SCHEDSTATS.
*/
/**
* account_group_user_time - Maintain utime for a thread group.
*
* @tsk: Pointer to task structure.
* @cputime: Time value by which to increment the utime field of the
* thread_group_cputime structure.
*
* If thread group time is being maintained, get the structure for the
* running CPU and update the utime field there.
*/
static inline void account_group_user_time(struct task_struct *tsk,
cputime_t cputime)
{
struct thread_group_cputimer *cputimer;
/* tsk == current, ensure it is safe to use ->signal */
if (unlikely(tsk->exit_state))
return;
cputimer = &tsk->signal->cputimer;
if (!cputimer->running)
return;
spin_lock(&cputimer->lock);
cputimer->cputime.utime =
cputime_add(cputimer->cputime.utime, cputime);
spin_unlock(&cputimer->lock);
}
/**
* account_group_system_time - Maintain stime for a thread group.
*
* @tsk: Pointer to task structure.
* @cputime: Time value by which to increment the stime field of the
* thread_group_cputime structure.
*
* If thread group time is being maintained, get the structure for the
* running CPU and update the stime field there.
*/
static inline void account_group_system_time(struct task_struct *tsk,
cputime_t cputime)
{
struct thread_group_cputimer *cputimer;
/* tsk == current, ensure it is safe to use ->signal */
if (unlikely(tsk->exit_state))
return;
cputimer = &tsk->signal->cputimer;
if (!cputimer->running)
return;
spin_lock(&cputimer->lock);
cputimer->cputime.stime =
cputime_add(cputimer->cputime.stime, cputime);
spin_unlock(&cputimer->lock);
}
/**
* account_group_exec_runtime - Maintain exec runtime for a thread group.
*
* @tsk: Pointer to task structure.
* @ns: Time value by which to increment the sum_exec_runtime field
* of the thread_group_cputime structure.
*
* If thread group time is being maintained, get the structure for the
* running CPU and update the sum_exec_runtime field there.
*/
static inline void account_group_exec_runtime(struct task_struct *tsk,
unsigned long long ns)
{
struct thread_group_cputimer *cputimer;
struct signal_struct *sig;
sig = tsk->signal;
/* see __exit_signal()->task_rq_unlock_wait() */
barrier();
if (unlikely(!sig))
return;
cputimer = &sig->cputimer;
if (!cputimer->running)
return;
spin_lock(&cputimer->lock);
cputimer->cputime.sum_exec_runtime += ns;
spin_unlock(&cputimer->lock);
}
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