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authorPeter Zijlstra <peterz@infradead.org>2015-06-09 11:13:36 +0200
committerIngo Molnar <mingo@kernel.org>2015-08-03 12:21:22 +0200
commitfbd705a0c6184580d0e2fbcbd47a37b6e5822511 (patch)
treec6e2e4369726d453bf695784c2d41528be909a50 /include/trace/events/sched.h
parent9d7fb04276481c59610983362d8e023d262b58ca (diff)
sched: Introduce the 'trace_sched_waking' tracepoint
Mathieu reported that since 317f394160e9 ("sched: Move the second half of ttwu() to the remote cpu") trace_sched_wakeup() can happen out of context of the waker. This is a problem when you want to analyse wakeup paths because it is now very hard to correlate the wakeup event to whoever issued the wakeup. OTOH trace_sched_wakeup() is issued at the point where we set p->state = TASK_RUNNING, which is right were we hand the task off to the scheduler, so this is an important point when looking at scheduling behaviour, up to here its been the wakeup path everything hereafter is due to scheduler policy. To bridge this gap, introduce a second tracepoint: trace_sched_waking. It is guaranteed to be called in the waker context. Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Francis Giraldeau <francis.giraldeau@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150609091336.GQ3644@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/trace/events/sched.h')
-rw-r--r--include/trace/events/sched.h30
1 files changed, 21 insertions, 9 deletions
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index d57a575fe31f..539d6bc3216a 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -55,9 +55,9 @@ TRACE_EVENT(sched_kthread_stop_ret,
*/
DECLARE_EVENT_CLASS(sched_wakeup_template,
- TP_PROTO(struct task_struct *p, int success),
+ TP_PROTO(struct task_struct *p),
- TP_ARGS(__perf_task(p), success),
+ TP_ARGS(__perf_task(p)),
TP_STRUCT__entry(
__array( char, comm, TASK_COMM_LEN )
@@ -71,25 +71,37 @@ DECLARE_EVENT_CLASS(sched_wakeup_template,
memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
__entry->pid = p->pid;
__entry->prio = p->prio;
- __entry->success = success;
+ __entry->success = 1; /* rudiment, kill when possible */
__entry->target_cpu = task_cpu(p);
),
- TP_printk("comm=%s pid=%d prio=%d success=%d target_cpu=%03d",
+ TP_printk("comm=%s pid=%d prio=%d target_cpu=%03d",
__entry->comm, __entry->pid, __entry->prio,
- __entry->success, __entry->target_cpu)
+ __entry->target_cpu)
);
+/*
+ * Tracepoint called when waking a task; this tracepoint is guaranteed to be
+ * called from the waking context.
+ */
+DEFINE_EVENT(sched_wakeup_template, sched_waking,
+ TP_PROTO(struct task_struct *p),
+ TP_ARGS(p));
+
+/*
+ * Tracepoint called when the task is actually woken; p->state == TASK_RUNNNG.
+ * It it not always called from the waking context.
+ */
DEFINE_EVENT(sched_wakeup_template, sched_wakeup,
- TP_PROTO(struct task_struct *p, int success),
- TP_ARGS(p, success));
+ TP_PROTO(struct task_struct *p),
+ TP_ARGS(p));
/*
* Tracepoint for waking up a new task:
*/
DEFINE_EVENT(sched_wakeup_template, sched_wakeup_new,
- TP_PROTO(struct task_struct *p, int success),
- TP_ARGS(p, success));
+ TP_PROTO(struct task_struct *p),
+ TP_ARGS(p));
#ifdef CREATE_TRACE_POINTS
static inline long __trace_sched_switch_state(struct task_struct *p)