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Subject[tip:timers/tracing] timers: Add tracepoints for timer_list timers
Commit-ID:  2b022e3d4bf9885f781221c59d86283a2cdfc2ed
Gitweb: http://git.kernel.org/tip/2b022e3d4bf9885f781221c59d86283a2cdfc2ed
Author: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
AuthorDate: Mon, 10 Aug 2009 10:48:59 +0800
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sat, 29 Aug 2009 14:10:06 +0200

timers: Add tracepoints for timer_list timers

Add tracepoints which cover the timer life cycle. The tracepoints are
integrated with the already existing debug_object debug points as far
as possible.

Based on patches from
Mathieu: http://marc.info/?l=linux-kernel&m=123791201816247&w=2
and
Anton: http://marc.info/?l=linux-kernel&m=124331396919301&w=2

[ tglx: Fixed timeout value in timer_start tracepoint, massaged
comments and made the printk's more readable ]

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Zhaolei <zhaolei@cn.fujitsu.com>
LKML-Reference: <4A7F8A9B.3040201@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>


---
include/trace/events/timer.h | 137 ++++++++++++++++++++++++++++++++++++++++++
kernel/timer.c | 32 +++++++++-
2 files changed, 165 insertions(+), 4 deletions(-)

diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h
new file mode 100644
index 0000000..725892a
--- /dev/null
+++ b/include/trace/events/timer.h
@@ -0,0 +1,137 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM timer
+
+#if !defined(_TRACE_TIMER_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_TIMER_H
+
+#include <linux/tracepoint.h>
+#include <linux/timer.h>
+
+/**
+ * timer_init - called when the timer is initialized
+ * @timer: pointer to struct timer_list
+ */
+TRACE_EVENT(timer_init,
+
+ TP_PROTO(struct timer_list *timer),
+
+ TP_ARGS(timer),
+
+ TP_STRUCT__entry(
+ __field( void *, timer )
+ ),
+
+ TP_fast_assign(
+ __entry->timer = timer;
+ ),
+
+ TP_printk("timer %p", __entry->timer)
+);
+
+/**
+ * timer_start - called when the timer is started
+ * @timer: pointer to struct timer_list
+ * @expires: the timers expiry time
+ */
+TRACE_EVENT(timer_start,
+
+ TP_PROTO(struct timer_list *timer, unsigned long expires),
+
+ TP_ARGS(timer, expires),
+
+ TP_STRUCT__entry(
+ __field( void *, timer )
+ __field( void *, function )
+ __field( unsigned long, expires )
+ __field( unsigned long, now )
+ ),
+
+ TP_fast_assign(
+ __entry->timer = timer;
+ __entry->function = timer->function;
+ __entry->expires = expires;
+ __entry->now = jiffies;
+ ),
+
+ TP_printk("timer %p: func %pf, expires %lu, timeout %ld",
+ __entry->timer, __entry->function, __entry->expires,
+ (long)__entry->expires - __entry->now)
+);
+
+/**
+ * timer_expire_entry - called immediately before the timer callback
+ * @timer: pointer to struct timer_list
+ *
+ * Allows to determine the timer latency.
+ */
+TRACE_EVENT(timer_expire_entry,
+
+ TP_PROTO(struct timer_list *timer),
+
+ TP_ARGS(timer),
+
+ TP_STRUCT__entry(
+ __field( void *, timer )
+ __field( unsigned long, now )
+ ),
+
+ TP_fast_assign(
+ __entry->timer = timer;
+ __entry->now = jiffies;
+ ),
+
+ TP_printk("timer %p: now %lu", __entry->timer, __entry->now)
+);
+
+/**
+ * timer_expire_exit - called immediately after the timer callback returns
+ * @timer: pointer to struct timer_list
+ *
+ * When used in combination with the timer_expire_entry tracepoint we can
+ * determine the runtime of the timer callback function.
+ *
+ * NOTE: Do NOT derefernce timer in TP_fast_assign. The pointer might
+ * be invalid. We solely track the pointer.
+ */
+TRACE_EVENT(timer_expire_exit,
+
+ TP_PROTO(struct timer_list *timer),
+
+ TP_ARGS(timer),
+
+ TP_STRUCT__entry(
+ __field(void *, timer )
+ ),
+
+ TP_fast_assign(
+ __entry->timer = timer;
+ ),
+
+ TP_printk("timer %p", __entry->timer)
+);
+
+/**
+ * timer_cancel - called when the timer is canceled
+ * @timer: pointer to struct timer_list
+ */
+TRACE_EVENT(timer_cancel,
+
+ TP_PROTO(struct timer_list *timer),
+
+ TP_ARGS(timer),
+
+ TP_STRUCT__entry(
+ __field( void *, timer )
+ ),
+
+ TP_fast_assign(
+ __entry->timer = timer;
+ ),
+
+ TP_printk("timer %p", __entry->timer)
+);
+
+#endif /* _TRACE_TIMER_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/kernel/timer.c b/kernel/timer.c
index 8e92be6..a7352b0 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -46,6 +46,9 @@
#include <asm/timex.h>
#include <asm/io.h>

+#define CREATE_TRACE_POINTS
+#include <trace/events/timer.h>
+
u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;

EXPORT_SYMBOL(jiffies_64);
@@ -521,6 +524,25 @@ static inline void debug_timer_activate(struct timer_list *timer) { }
static inline void debug_timer_deactivate(struct timer_list *timer) { }
#endif

+static inline void debug_init(struct timer_list *timer)
+{
+ debug_timer_init(timer);
+ trace_timer_init(timer);
+}
+
+static inline void
+debug_activate(struct timer_list *timer, unsigned long expires)
+{
+ debug_timer_activate(timer);
+ trace_timer_start(timer, expires);
+}
+
+static inline void debug_deactivate(struct timer_list *timer)
+{
+ debug_timer_deactivate(timer);
+ trace_timer_cancel(timer);
+}
+
static void __init_timer(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
@@ -549,7 +571,7 @@ void init_timer_key(struct timer_list *timer,
const char *name,
struct lock_class_key *key)
{
- debug_timer_init(timer);
+ debug_init(timer);
__init_timer(timer, name, key);
}
EXPORT_SYMBOL(init_timer_key);
@@ -568,7 +590,7 @@ static inline void detach_timer(struct timer_list *timer,
{
struct list_head *entry = &timer->entry;

- debug_timer_deactivate(timer);
+ debug_deactivate(timer);

__list_del(entry->prev, entry->next);
if (clear_pending)
@@ -632,7 +654,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires,
goto out_unlock;
}

- debug_timer_activate(timer);
+ debug_activate(timer, expires);

new_base = __get_cpu_var(tvec_bases);

@@ -787,7 +809,7 @@ void add_timer_on(struct timer_list *timer, int cpu)
BUG_ON(timer_pending(timer) || !timer->function);
spin_lock_irqsave(&base->lock, flags);
timer_set_base(timer, base);
- debug_timer_activate(timer);
+ debug_activate(timer, timer->expires);
if (time_before(timer->expires, base->next_timer) &&
!tbase_get_deferrable(timer->base))
base->next_timer = timer->expires;
@@ -1000,7 +1022,9 @@ static inline void __run_timers(struct tvec_base *base)
*/
lock_map_acquire(&lockdep_map);

+ trace_timer_expire_entry(timer);
fn(data);
+ trace_timer_expire_exit(timer);

lock_map_release(&lockdep_map);


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