[RFC][PATCH 2/2] [PATCH 2/2] tracing: Only trace sched_wakeup if it actually work something up

[Steven Rostedt <rostedt@goodmis.org>]

[-- Attachment #1: 0002-tracing-Only-trace-sched_wakeup-if-it-actually-work-.patch --]
[-- Type: text/plain, Size: 1976 bytes --]

From: Steven Rostedt <srostedt@redhat.com>

Currently the tracepoint sched_wakeup traces the wakeup event even
if the wakeup failed to wake anything up. This is quite stupid
but it happens because we did not want to add a conditional
to the core kernel code that would just slow down the wakeup events.

This patch changes the wakeup tracepoints to use the

 DECLARE_EVENT_CLASS_CONDITIONAL()

to test the "success" parameter and will only trace the event if
the wakeup was successfull.

The success field in the tracepoint is removed since it is no
longer needed.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/sched.h |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 67456f0..0807a25 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -52,17 +52,18 @@ TRACE_EVENT(sched_kthread_stop_ret,
 /*
  * Tracepoint for waking up a task:
  */
-DECLARE_EVENT_CLASS(sched_wakeup_template,
+DECLARE_EVENT_CLASS_CONDITION(sched_wakeup_template,
 
 	TP_PROTO(struct task_struct *p, int success),
 
 	TP_ARGS(p, success),
 
+	TP_CONDITION(success),
+
 	TP_STRUCT__entry(
 		__array(	char,	comm,	TASK_COMM_LEN	)
 		__field(	pid_t,	pid			)
 		__field(	int,	prio			)
-		__field(	int,	success			)
 		__field(	int,	target_cpu		)
 	),
 
@@ -70,13 +71,12 @@ 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->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)
 );
 
 DEFINE_EVENT(sched_wakeup_template, sched_wakeup,
-- 
1.7.2.3