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Commit c6a2a177 authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Thomas Gleixner
Browse files

hrtimer: Add tracepoint for hrtimers 



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

[ tglx: Fixed comments, made output conistent, easier to read and
  	parse. Fixed output for 32bit archs which do not use the
  	scalar representation of ktime_t. Hand current time to
  	trace_hrtimer_expiry_entry instead of calling get_time()
  	inside of the trace assignment. ]

Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Anton Blanchard <anton@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Zhaolei <zhaolei@cn.fujitsu.com>
LKML-Reference: <4A7F8B2B.5020908@cn.fujitsu.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 2b022e3d

include/trace/events/timer.h

+139 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#define _TRACE_TIMER_H



#include <linux/tracepoint.h>

#include <linux/hrtimer.h>

#include <linux/timer.h>



/**
@@ -131,6 +132,144 @@ TRACE_EVENT(timer_cancel, 
	TP_printk("timer %p", __entry->timer)

);



/**

 * hrtimer_init - called when the hrtimer is initialized

 * @timer:	pointer to struct hrtimer

 * @clockid:	the hrtimers clock

 * @mode:	the hrtimers mode

 */

TRACE_EVENT(hrtimer_init,



	TP_PROTO(struct hrtimer *timer, clockid_t clockid,

		 enum hrtimer_mode mode),



	TP_ARGS(timer, clockid, mode),



	TP_STRUCT__entry(

		__field( void *,		timer		)

		__field( clockid_t,		clockid		)

		__field( enum hrtimer_mode,	mode		)

	),



	TP_fast_assign(

		__entry->timer		= timer;

		__entry->clockid	= clockid;

		__entry->mode		= mode;

	),



	TP_printk("hrtimer %p, clockid %s, mode %s", __entry->timer,

		  __entry->clockid == CLOCK_REALTIME ?

			"CLOCK_REALTIME" : "CLOCK_MONOTONIC",

		  __entry->mode == HRTIMER_MODE_ABS ?

			"HRTIMER_MODE_ABS" : "HRTIMER_MODE_REL")

);



/**

 * hrtimer_start - called when the hrtimer is started

 * @timer: pointer to struct hrtimer

 */

TRACE_EVENT(hrtimer_start,



	TP_PROTO(struct hrtimer *timer),



	TP_ARGS(timer),



	TP_STRUCT__entry(

		__field( void *,	timer		)

		__field( void *,	function	)

		__field( s64,		expires		)

		__field( s64,		softexpires	)

	),



	TP_fast_assign(

		__entry->timer		= timer;

		__entry->function	= timer->function;

		__entry->expires	= hrtimer_get_expires(timer).tv64;

		__entry->softexpires	= hrtimer_get_softexpires(timer).tv64;

	),



	TP_printk("hrtimer %p, func %pf, expires %llu, softexpires %llu",

		  __entry->timer, __entry->function,

		  (unsigned long long)ktime_to_ns((ktime_t) {

				  .tv64 = __entry->expires }),

		  (unsigned long long)ktime_to_ns((ktime_t) {

				  .tv64 = __entry->softexpires }))

);



/**

 * htimmer_expire_entry - called immediately before the hrtimer callback

 * @timer:	pointer to struct hrtimer

 * @now:	pointer to variable which contains current time of the

 *		timers base.

 *

 * Allows to determine the timer latency.

 */

TRACE_EVENT(hrtimer_expire_entry,



	TP_PROTO(struct hrtimer *timer, ktime_t *now),



	TP_ARGS(timer, now),



	TP_STRUCT__entry(

		__field( void *,	timer	)

		__field( s64,		now	)

	),



	TP_fast_assign(

		__entry->timer	= timer;

		__entry->now	= now->tv64;

	),



	TP_printk("hrtimer %p, now %llu", __entry->timer,

		  (unsigned long long)ktime_to_ns((ktime_t) {

				  .tv64 = __entry->now }))

 );



/**

 * hrtimer_expire_exit - called immediately after the hrtimer callback returns

 * @timer:	pointer to struct hrtimer

 *

 * When used in combination with the hrtimer_expire_entry tracepoint we can

 * determine the runtime of the callback function.

 */

TRACE_EVENT(hrtimer_expire_exit,



	TP_PROTO(struct hrtimer *timer),



	TP_ARGS(timer),



	TP_STRUCT__entry(

		__field( void *,	timer	)

	),



	TP_fast_assign(

		__entry->timer	= timer;

	),



	TP_printk("hrtimer %p", __entry->timer)

);



/**

 * hrtimer_cancel - called when the hrtimer is canceled

 * @timer:	pointer to struct hrtimer

 */

TRACE_EVENT(hrtimer_cancel,



	TP_PROTO(struct hrtimer *timer),



	TP_ARGS(timer),



	TP_STRUCT__entry(

		__field( void *,	timer	)

	),



	TP_fast_assign(

		__entry->timer	= timer;

	),



	TP_printk("hrtimer %p", __entry->timer)

);



#endif /*  _TRACE_TIMER_H */



/* This part must be outside protection */

kernel/hrtimer.c

+32 −8
Original line number Diff line number Diff line
@@ -48,6 +48,8 @@ 


#include <asm/uaccess.h>



#include <trace/events/timer.h>



/*

 * The timer bases:

 *
@@ -441,6 +443,26 @@ static inline void debug_hrtimer_activate(struct hrtimer *timer) { } 
static inline void debug_hrtimer_deactivate(struct hrtimer *timer) { }

#endif



static inline void

debug_init(struct hrtimer *timer, clockid_t clockid,

	   enum hrtimer_mode mode)

{

	debug_hrtimer_init(timer);

	trace_hrtimer_init(timer, clockid, mode);

}



static inline void debug_activate(struct hrtimer *timer)

{

	debug_hrtimer_activate(timer);

	trace_hrtimer_start(timer);

}



static inline void debug_deactivate(struct hrtimer *timer)

{

	debug_hrtimer_deactivate(timer);

	trace_hrtimer_cancel(timer);

}



/* High resolution timer related functions */

#ifdef CONFIG_HIGH_RES_TIMERS
@@ -797,7 +819,7 @@ static int enqueue_hrtimer(struct hrtimer *timer, 
	struct hrtimer *entry;

	int leftmost = 1;



	debug_hrtimer_activate(timer);

	debug_activate(timer);



	/*

	 * Find the right place in the rbtree:
@@ -883,7 +905,7 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base) 
		 * reprogramming happens in the interrupt handler. This is a

		 * rare case and less expensive than a smp call.

		 */

		debug_hrtimer_deactivate(timer);

		debug_deactivate(timer);

		timer_stats_hrtimer_clear_start_info(timer);

		reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);

		__remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE,
@@ -1116,7 +1138,7 @@ static void __hrtimer_init(struct hrtimer *timer, clockid_t clock_id, 
void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,

		  enum hrtimer_mode mode)

{

	debug_hrtimer_init(timer);

	debug_init(timer, clock_id, mode);

	__hrtimer_init(timer, clock_id, mode);

}

EXPORT_SYMBOL_GPL(hrtimer_init);
@@ -1140,7 +1162,7 @@ int hrtimer_get_res(const clockid_t which_clock, struct timespec *tp) 
}

EXPORT_SYMBOL_GPL(hrtimer_get_res);



static void __run_hrtimer(struct hrtimer *timer)

static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)

{

	struct hrtimer_clock_base *base = timer->base;

	struct hrtimer_cpu_base *cpu_base = base->cpu_base;
@@ -1149,7 +1171,7 @@ static void __run_hrtimer(struct hrtimer *timer) 


	WARN_ON(!irqs_disabled());



	debug_hrtimer_deactivate(timer);

	debug_deactivate(timer);

	__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);

	timer_stats_account_hrtimer(timer);

	fn = timer->function;
@@ -1160,7 +1182,9 @@ static void __run_hrtimer(struct hrtimer *timer) 
	 * the timer base.

	 */

	spin_unlock(&cpu_base->lock);

	trace_hrtimer_expire_entry(timer, now);

	restart = fn(timer);

	trace_hrtimer_expire_exit(timer);

	spin_lock(&cpu_base->lock);



	/*
@@ -1271,7 +1295,7 @@ void hrtimer_interrupt(struct clock_event_device *dev) 
				break;

			}



			__run_hrtimer(timer);

			__run_hrtimer(timer, &basenow);

		}

		base++;

	}
@@ -1393,7 +1417,7 @@ void hrtimer_run_queues(void) 
					hrtimer_get_expires_tv64(timer))

				break;



			__run_hrtimer(timer);

			__run_hrtimer(timer, &base->softirq_time);

		}

		spin_unlock(&cpu_base->lock);

	}
@@ -1569,7 +1593,7 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, 
	while ((node = rb_first(&old_base->active))) {

		timer = rb_entry(node, struct hrtimer, node);

		BUG_ON(hrtimer_callback_running(timer));

		debug_hrtimer_deactivate(timer);

		debug_deactivate(timer);



		/*

		 * Mark it as STATE_MIGRATE not INACTIVE otherwise the