Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753933AbZG1Mn7 (ORCPT ); Tue, 28 Jul 2009 08:43:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751581AbZG1Mn6 (ORCPT ); Tue, 28 Jul 2009 08:43:58 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:60511 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751431AbZG1Mn5 (ORCPT ); Tue, 28 Jul 2009 08:43:57 -0400 Message-ID: <4A6EF27C.7010605@cn.fujitsu.com> Date: Tue, 28 Jul 2009 20:43:40 +0800 From: Xiao Guangrong User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: Ingo Molnar CC: Thomas Gleixner , Peter Zijlstra , Steven Rostedt , Frederic Weisbecker , Mathieu Desnoyers , Zhaolei , kosaki.motohiro@jp.fujitsu.com, Anton Blanchard , LKML Subject: [PATCH v4 1/3] ftrace: add tracepoint for timer Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7624 Lines: 281 This patch is modify from Mathieu's patch base on Ingo's suggestion, the original patch can be found here: http://marc.info/?l=linux-kernel&m=123791201816247&w=2 Great thanks to Thomas for giving me so many valuable advices. Those tracepoints are wanted and useful: 1: We can detect a timer's delay 2: We can monitor the lifecycle and behaviors of a timer Thus they help in analysing and debuging. Example ftrace output: insmod-1712 [000] 145.901459: timer_init: timer=d0ace4b4 insmod-1712 [000] 145.901469: timer_start: timer=d0ace4b4 func=timer_fun expires=4294813629 timeout=199 -0 [000] 146.100230: timer_cancel: timer=d0ace4b4 -0 [000] 146.100233: timer_expire: timer=d0ace4b4 jiffies=4294813629 -0 [000] 146.100627: timer_callback_done: func=d0ace4b4 We expect the timer expires at 4294813629, after 199 jiffies, actually the timer expires at 4294813629, so it is delayed by 0 jiffies. We also realize the timer's callback started at 146.100233, and it finished at 146.100627, so it's taking 146.100627-146.100233=0.4ms. Changelog: v1->v2: 1: Add jiffies info into timer 2: Combine debugobjects and trace as Thomas's suggestion v2->v3: 1: Remove function address from timer_expire and timer_cancel as Thomas's suggestion 2: Remove debug_and_trace_timer_expire() as Thomas's suggestion 3: Rename trace_timer_entry() and trace_timer_exit() to match this patch v3->v4: 1: Rename debug_and_trace_*() to debug_*() as Peter Zijlstra's suggestion 2: Integrate Anton Blanchard's patch, which can been found at: http://marc.info/?l=linux-kernel&m=124331396919301&w=2 Signed-off-by: Anton Blanchard Signed-off-by: Mathieu Desnoyers Signed-off-by: Xiao Guangrong --- include/trace/events/timer.h | 134 ++++++++++++++++++++++++++++++++++++++++++ kernel/timer.c | 32 +++++++++- 2 files changed, 162 insertions(+), 4 deletions(-) create mode 100644 include/trace/events/timer.h diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h new file mode 100644 index 0000000..a664afa --- /dev/null +++ b/include/trace/events/timer.h @@ -0,0 +1,134 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM timer + +#if !defined(_TRACE_TIMER_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_TIMER_H + +#include +#include + +/** + * 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 timer's expire 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( int, timeout ) + ), + + TP_fast_assign( + __entry->timer = timer; + __entry->function = timer->function; + __entry->expires = expires; + __entry->timeout = timer->expires - jiffies; + ), + + TP_printk("timer=%p func=%pf expires=%lu timeout=%d", __entry->timer, + __entry->function, __entry->expires, __entry->timeout) +); + +/** + * timer_expire - called immediately before the timer callback + * @timer: pointer to struct timer_list + * + * When used in combination with the timer_callback_done tracepoint we can + * determine the timer latency. + **/ +TRACE_EVENT(timer_expire, + + TP_PROTO(struct timer_list *timer), + + TP_ARGS(timer), + + TP_STRUCT__entry( + __field( void *, timer ) + __field( unsigned long, jiffies ) + ), + + TP_fast_assign( + __entry->timer = timer; + __entry->jiffies = jiffies; + ), + + TP_printk("timer=%p jiffies=%lu", __entry->timer, __entry->jiffies) +); + +/** + * timer_callback_done - called immediately after the timer callback returns + * @timer: pointer to struct timer_list + * + * When used in combination with the timer_expire tracepoint we can + * determine the timer latency. + **/ +TRACE_EVENT(timer_callback_done, + + TP_PROTO(struct timer_list *timer), + + TP_ARGS(timer), + + TP_STRUCT__entry( + __field(void *, timer ) + ), + + TP_fast_assign( + __entry->timer = timer; + ), + + TP_printk("func=%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 diff --git a/kernel/timer.c b/kernel/timer.c index a7f07d5..92ff6a7 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -46,6 +46,9 @@ #include #include +#define CREATE_TRACE_POINTS +#include + u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; EXPORT_SYMBOL(jiffies_64); @@ -520,6 +523,25 @@ 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) @@ -548,7 +570,7 @@ 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); @@ -567,7 +589,7 @@ 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) @@ -628,7 +650,7 @@ __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); @@ -780,7 +802,7 @@ 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); internal_add_timer(base, timer); /* * Check whether the other CPU is idle and needs to be @@ -984,7 +1006,9 @@ static inline void __run_timers(struct tvec_base *base) */ lock_map_acquire(&lockdep_map); + trace_timer_expire(timer); fn(data); + trace_timer_callback_done(timer); lock_map_release(&lockdep_map); -- 1.6.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/