Messages in this thread Patch in this message | | | From | Arun Sharma <> | Subject | [PATCH 2/2] tracing, sched: Add a new tracepoint for sleeptime | Date | Tue, 20 Dec 2011 10:09:18 -0800 |
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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.
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> Cc: 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> Cc: Ingo Molnar <mingo@elte.hu> Cc: linux-kernel@vger.kernel.org --- include/trace/events/sched.h | 48 ++++++++++++++++++++++++++++++++++++++++++ kernel/sched/core.c | 1 + 2 files changed, 49 insertions(+), 0 deletions(-)
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index 959ff18..5189220 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -363,6 +363,54 @@ 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; + + 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. diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ca8fd44..172e6ee 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1899,6 +1899,7 @@ 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) -- 1.7.4
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