From 82f67cd9fca8c8762c15ba7ed0d5747588c1e221 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 16 Feb 2007 01:28:13 -0800 Subject: [PATCH] Add debugging feature /proc/timer_stat Add /proc/timer_stats support: debugging feature to profile timer expiration. Both the starting site, process/PID and the expiration function is captured. This allows the quick identification of timer event sources in a system. Sample output: # echo 1 > /proc/timer_stats # cat /proc/timer_stats Timer Stats Version: v0.1 Sample period: 4.010 s 24, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 11, 0 swapper sk_reset_timer (tcp_delack_timer) 6, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 17, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 4, 2050 pcscd do_nanosleep (hrtimer_wakeup) 5, 4179 sshd sk_reset_timer (tcp_write_timer) 4, 2248 yum-updatesd schedule_timeout (process_timeout) 18, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 3, 0 swapper sk_reset_timer (tcp_delack_timer) 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer) 2, 1 swapper e1000_up (e1000_watchdog) 1, 1 init schedule_timeout (process_timeout) 100 total events, 25.24 events/sec [ cleanups and hrtimers support from Thomas Gleixner ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Cc: john stultz Cc: Roman Zippel Cc: Andi Kleen Signed-off-by: Adrian Bunk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/timer.c | 31 +++++++++++++++++++++++++++++-- 1 file changed, 29 insertions(+), 2 deletions(-) (limited to 'kernel/timer.c') diff --git a/kernel/timer.c b/kernel/timer.c index f058e6cfd50c..c3c67f3c0190 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include @@ -263,6 +264,18 @@ static void internal_add_timer(tvec_base_t *base, struct timer_list *timer) list_add_tail(&timer->entry, vec); } +#ifdef CONFIG_TIMER_STATS +void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr) +{ + if (timer->start_site) + return; + + timer->start_site = addr; + memcpy(timer->start_comm, current->comm, TASK_COMM_LEN); + timer->start_pid = current->pid; +} +#endif + /** * init_timer - initialize a timer. * @timer: the timer to be initialized @@ -274,11 +287,16 @@ void fastcall init_timer(struct timer_list *timer) { timer->entry.next = NULL; timer->base = __raw_get_cpu_var(tvec_bases); +#ifdef CONFIG_TIMER_STATS + timer->start_site = NULL; + timer->start_pid = -1; + memset(timer->start_comm, 0, TASK_COMM_LEN); +#endif } EXPORT_SYMBOL(init_timer); static inline void detach_timer(struct timer_list *timer, - int clear_pending) + int clear_pending) { struct list_head *entry = &timer->entry; @@ -325,6 +343,7 @@ int __mod_timer(struct timer_list *timer, unsigned long expires) unsigned long flags; int ret = 0; + timer_stats_timer_set_start_info(timer); BUG_ON(!timer->function); base = lock_timer_base(timer, &flags); @@ -375,6 +394,7 @@ void add_timer_on(struct timer_list *timer, int cpu) tvec_base_t *base = per_cpu(tvec_bases, cpu); unsigned long flags; + timer_stats_timer_set_start_info(timer); BUG_ON(timer_pending(timer) || !timer->function); spin_lock_irqsave(&base->lock, flags); timer->base = base; @@ -407,6 +427,7 @@ int mod_timer(struct timer_list *timer, unsigned long expires) { BUG_ON(!timer->function); + timer_stats_timer_set_start_info(timer); /* * This is a common optimization triggered by the * networking code - if the timer is re-modified @@ -437,6 +458,7 @@ int del_timer(struct timer_list *timer) unsigned long flags; int ret = 0; + timer_stats_timer_clear_start_info(timer); if (timer_pending(timer)) { base = lock_timer_base(timer, &flags); if (timer_pending(timer)) { @@ -570,6 +592,8 @@ static inline void __run_timers(tvec_base_t *base) fn = timer->function; data = timer->data; + timer_stats_account_timer(timer); + set_running_timer(base, timer); detach_timer(timer, 1); spin_unlock_irq(&base->lock); @@ -1229,7 +1253,8 @@ static void run_timer_softirq(struct softirq_action *h) { tvec_base_t *base = __get_cpu_var(tvec_bases); - hrtimer_run_queues(); + hrtimer_run_queues(); + if (time_after_eq(jiffies, base->timer_jiffies)) __run_timers(base); } @@ -1675,6 +1700,8 @@ void __init init_timers(void) int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE, (void *)(long)smp_processor_id()); + init_timer_stats(); + BUG_ON(err == NOTIFY_BAD); register_cpu_notifier(&timers_nb); open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL); -- cgit v1.2.3-59-g8ed1b