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sched/tracing: Add a new tracepoint for sleeptime 

If CONFIG_SCHEDSTATS is defined, the kernel maintains
information about how long the task was sleeping or
in the case of iowait, blocking in the kernel before
getting woken up.

This will be useful for sleep time profiling.

Note: this information is only provided for sched_fair.
Other scheduling classes may choose to provide this in
the future.

Note: the delay includes the time spent on the runqueue
as well.

Signed-off-by: Arun Sharma <asharma@fb.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Andrew Vagin <avagin@openvz.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1324512940-32060-2-git-send-email-asharma@fb.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Arun Sharma 2011-12-21 16:15:40 -08:00 committed by Ingo Molnar
parent 664dfa65e8
commit 1ac9bc6943
3 changed files with 51 additions and 2 deletions
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50
include/trace/events/sched.h
View File

@ -370,6 +370,56 @@ TRACE_EVENT(sched_stat_runtime,
(unsigned long long)__entry->vruntime)
);
#ifdef CREATE_TRACE_POINTS
static inline u64 trace_get_sleeptime(struct task_struct *tsk)
{
#ifdef CONFIG_SCHEDSTATS
u64 block, sleep;
block = tsk->se.statistics.block_start;
sleep = tsk->se.statistics.sleep_start;
tsk->se.statistics.block_start = 0;
tsk->se.statistics.sleep_start = 0;
return block ? block : sleep ? sleep : 0;
#else
return 0;
#endif
}
#endif
/*
* Tracepoint for accounting sleeptime (time the task is sleeping
* or waiting for I/O).
*/
TRACE_EVENT(sched_stat_sleeptime,
TP_PROTO(struct task_struct *tsk, u64 now),
TP_ARGS(tsk, now),
TP_STRUCT__entry(
__array( char, comm, TASK_COMM_LEN )
__field( pid_t, pid )
__field( u64, sleeptime )
),
TP_fast_assign(
memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
__entry->pid = tsk->pid;
__entry->sleeptime = trace_get_sleeptime(tsk);
__entry->sleeptime = __entry->sleeptime ?
now - __entry->sleeptime : 0;
)
TP_perf_assign(
__perf_count(__entry->sleeptime);
),
TP_printk("comm=%s pid=%d sleeptime=%Lu [ns]",
__entry->comm, __entry->pid,
(unsigned long long)__entry->sleeptime)
);
/*
* Tracepoint for showing priority inheritance modifying a tasks
* priority.

1
kernel/sched/core.c
View File

@ -1937,6 +1937,7 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
local_irq_enable();
#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
finish_lock_switch(rq, prev);
trace_sched_stat_sleeptime(current, rq->clock);
fire_sched_in_preempt_notifiers(current);
if (mm)

2
kernel/sched/fair.c
View File

@ -1003,7 +1003,6 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
if (unlikely(delta > se->statistics.sleep_max))
se->statistics.sleep_max = delta;
se->statistics.sleep_start = 0;
se->statistics.sum_sleep_runtime += delta;
if (tsk) {
@ -1020,7 +1019,6 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
if (unlikely(delta > se->statistics.block_max))
se->statistics.block_max = delta;
se->statistics.block_start = 0;
se->statistics.sum_sleep_runtime += delta;
if (tsk) {