[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 <tglx@linutronix.de> ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Ingo Molnar
Linus Torvalds
parent
8bfd9a7a22
commit
82f67cd9fc
9 changed files with 650 additions and 4 deletions
68
Documentation/hrtimer/timer_stats.txt
Normal file
68
Documentation/hrtimer/timer_stats.txt
Normal file
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@ -0,0 +1,68 @@
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timer_stats - timer usage statistics
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------------------------------------
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timer_stats is a debugging facility to make the timer (ab)usage in a Linux
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system visible to kernel and userspace developers. It is not intended for
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production usage as it adds significant overhead to the (hr)timer code and the
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(hr)timer data structures.
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timer_stats should be used by kernel and userspace developers to verify that
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their code does not make unduly use of timers. This helps to avoid unnecessary
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wakeups, which should be avoided to optimize power consumption.
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It can be enabled by CONFIG_TIMER_STATS in the "Kernel hacking" configuration
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section.
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timer_stats collects information about the timer events which are fired in a
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Linux system over a sample period:
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- the pid of the task(process) which initialized the timer
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- the name of the process which initialized the timer
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- the function where the timer was intialized
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- the callback function which is associated to the timer
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- the number of events (callbacks)
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timer_stats adds an entry to /proc: /proc/timer_stats
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This entry is used to control the statistics functionality and to read out the
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sampled information.
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The timer_stats functionality is inactive on bootup.
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To activate a sample period issue:
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# echo 1 >/proc/timer_stats
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To stop a sample period issue:
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# echo 0 >/proc/timer_stats
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The statistics can be retrieved by:
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# cat /proc/timer_stats
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The readout of /proc/timer_stats automatically disables sampling. The sampled
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information is kept until a new sample period is started. This allows multiple
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readouts.
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Sample output of /proc/timer_stats:
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Timerstats sample period: 3.888770 s
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12, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick)
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15, 1 swapper hcd_submit_urb (rh_timer_func)
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4, 959 kedac schedule_timeout (process_timeout)
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1, 0 swapper page_writeback_init (wb_timer_fn)
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28, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick)
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22, 2948 IRQ 4 tty_flip_buffer_push (delayed_work_timer_fn)
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3, 3100 bash schedule_timeout (process_timeout)
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1, 1 swapper queue_delayed_work_on (delayed_work_timer_fn)
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1, 1 swapper queue_delayed_work_on (delayed_work_timer_fn)
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1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer)
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1, 2292 ip __netdev_watchdog_up (dev_watchdog)
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1, 23 events/1 do_cache_clean (delayed_work_timer_fn)
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90 total events, 30.0 events/sec
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The first column is the number of events, the second column the pid, the third
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column is the name of the process. The forth column shows the function which
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initialized the timer and in parantheses the callback function which was
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executed on expiry.
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Thomas, Ingo
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@ -119,6 +119,11 @@ struct hrtimer {
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enum hrtimer_cb_mode cb_mode;
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struct list_head cb_entry;
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#endif
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#ifdef CONFIG_TIMER_STATS
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void *start_site;
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char start_comm[16];
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int start_pid;
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#endif
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};
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/**
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@ -311,4 +316,44 @@ extern unsigned long ktime_divns(const ktime_t kt, s64 div);
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# define ktime_divns(kt, div) (unsigned long)((kt).tv64 / (div))
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#endif
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/*
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* Timer-statistics info:
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*/
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#ifdef CONFIG_TIMER_STATS
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extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
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void *timerf, char * comm);
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static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
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{
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timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
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timer->function, timer->start_comm);
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}
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extern void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer,
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void *addr);
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static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
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{
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__timer_stats_hrtimer_set_start_info(timer, __builtin_return_address(0));
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}
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static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
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{
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timer->start_site = NULL;
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}
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#else
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static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
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{
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}
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static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
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{
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}
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static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
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{
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}
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#endif
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#endif
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@ -2,6 +2,7 @@
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#define _LINUX_TIMER_H
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#include <linux/list.h>
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#include <linux/ktime.h>
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#include <linux/spinlock.h>
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#include <linux/stddef.h>
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@ -15,6 +16,11 @@ struct timer_list {
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unsigned long data;
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struct tvec_t_base_s *base;
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#ifdef CONFIG_TIMER_STATS
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void *start_site;
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char start_comm[16];
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int start_pid;
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#endif
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};
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extern struct tvec_t_base_s boot_tvec_bases;
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@ -73,6 +79,54 @@ extern unsigned long next_timer_interrupt(void);
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*/
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extern unsigned long get_next_timer_interrupt(unsigned long now);
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/*
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* Timer-statistics info:
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*/
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#ifdef CONFIG_TIMER_STATS
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extern void init_timer_stats(void);
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extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
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void *timerf, char * comm);
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static inline void timer_stats_account_timer(struct timer_list *timer)
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{
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timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
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timer->function, timer->start_comm);
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}
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extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
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void *addr);
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static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
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{
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__timer_stats_timer_set_start_info(timer, __builtin_return_address(0));
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}
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static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
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{
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timer->start_site = NULL;
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}
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#else
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static inline void init_timer_stats(void)
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{
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}
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static inline void timer_stats_account_timer(struct timer_list *timer)
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{
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}
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static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
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{
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}
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static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
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{
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}
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#endif
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extern void delayed_work_timer_fn(unsigned long __data);
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/**
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* add_timer - start a timer
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* @timer: the timer to be added
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@ -585,6 +585,18 @@ static inline void hrtimer_init_timer_hres(struct hrtimer *timer) { }
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#endif /* CONFIG_HIGH_RES_TIMERS */
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#ifdef CONFIG_TIMER_STATS
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void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer, void *addr)
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{
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if (timer->start_site)
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return;
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timer->start_site = addr;
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memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
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timer->start_pid = current->pid;
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}
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#endif
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/*
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* Counterpart to lock_timer_base above:
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*/
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@ -743,6 +755,7 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
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* reprogramming happens in the interrupt handler. This is a
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* rare case and less expensive than a smp call.
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*/
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timer_stats_hrtimer_clear_start_info(timer);
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reprogram = base->cpu_base == &__get_cpu_var(hrtimer_bases);
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__remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE,
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reprogram);
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@ -791,6 +804,8 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
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}
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timer->expires = tim;
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timer_stats_hrtimer_set_start_info(timer);
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enqueue_hrtimer(timer, new_base, base == new_base);
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unlock_hrtimer_base(timer, &flags);
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@ -925,6 +940,12 @@ void hrtimer_init(struct hrtimer *timer, clockid_t clock_id,
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timer->base = &cpu_base->clock_base[clock_id];
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hrtimer_init_timer_hres(timer);
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#ifdef CONFIG_TIMER_STATS
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timer->start_site = NULL;
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timer->start_pid = -1;
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memset(timer->start_comm, 0, TASK_COMM_LEN);
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#endif
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}
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EXPORT_SYMBOL_GPL(hrtimer_init);
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@ -1006,6 +1027,7 @@ void hrtimer_interrupt(struct clock_event_device *dev)
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__remove_hrtimer(timer, base,
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HRTIMER_STATE_CALLBACK, 0);
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timer_stats_account_hrtimer(timer);
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/*
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* Note: We clear the CALLBACK bit after
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@ -1050,6 +1072,8 @@ static void run_hrtimer_softirq(struct softirq_action *h)
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timer = list_entry(cpu_base->cb_pending.next,
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struct hrtimer, cb_entry);
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timer_stats_account_hrtimer(timer);
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fn = timer->function;
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__remove_hrtimer(timer, timer->base, HRTIMER_STATE_CALLBACK, 0);
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spin_unlock_irq(&cpu_base->lock);
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@ -1106,6 +1130,8 @@ static inline void run_hrtimer_queue(struct hrtimer_cpu_base *cpu_base,
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if (base->softirq_time.tv64 <= timer->expires.tv64)
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break;
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timer_stats_account_hrtimer(timer);
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fn = timer->function;
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__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK, 0);
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spin_unlock_irq(&cpu_base->lock);
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@ -5,3 +5,4 @@ obj-$(CONFIG_GENERIC_CLOCKEVENTS) += tick-common.o
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obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) += tick-broadcast.o
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obj-$(CONFIG_TICK_ONESHOT) += tick-oneshot.o
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obj-$(CONFIG_TICK_ONESHOT) += tick-sched.o
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obj-$(CONFIG_TIMER_STATS) += timer_stats.o
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411
kernel/time/timer_stats.c
Normal file
411
kernel/time/timer_stats.c
Normal file
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@ -0,0 +1,411 @@
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/*
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* kernel/time/timer_stats.c
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*
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* Collect timer usage statistics.
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*
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* Copyright(C) 2006, Red Hat, Inc., Ingo Molnar
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* Copyright(C) 2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
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*
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* timer_stats is based on timer_top, a similar functionality which was part of
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* Con Kolivas dyntick patch set. It was developed by Daniel Petrini at the
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* Instituto Nokia de Tecnologia - INdT - Manaus. timer_top's design was based
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* on dynamic allocation of the statistics entries and linear search based
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* lookup combined with a global lock, rather than the static array, hash
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* and per-CPU locking which is used by timer_stats. It was written for the
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* pre hrtimer kernel code and therefore did not take hrtimers into account.
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* Nevertheless it provided the base for the timer_stats implementation and
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* was a helpful source of inspiration. Kudos to Daniel and the Nokia folks
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* for this effort.
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*
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* timer_top.c is
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* Copyright (C) 2005 Instituto Nokia de Tecnologia - INdT - Manaus
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* Written by Daniel Petrini <d.pensator@gmail.com>
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* timer_top.c was released under the GNU General Public License version 2
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*
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* We export the addresses and counting of timer functions being called,
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* the pid and cmdline from the owner process if applicable.
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*
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* Start/stop data collection:
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* # echo 1[0] >/proc/timer_stats
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*
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* Display the information collected so far:
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* # cat /proc/timer_stats
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/proc_fs.h>
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#include <linux/module.h>
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#include <linux/spinlock.h>
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#include <linux/sched.h>
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#include <linux/seq_file.h>
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#include <linux/kallsyms.h>
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#include <asm/uaccess.h>
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/*
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* This is our basic unit of interest: a timer expiry event identified
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* by the timer, its start/expire functions and the PID of the task that
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* started the timer. We count the number of times an event happens:
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*/
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struct entry {
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/*
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* Hash list:
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*/
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struct entry *next;
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/*
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* Hash keys:
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*/
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void *timer;
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void *start_func;
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void *expire_func;
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pid_t pid;
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/*
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* Number of timeout events:
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*/
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unsigned long count;
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/*
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* We save the command-line string to preserve
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* this information past task exit:
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*/
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char comm[TASK_COMM_LEN + 1];
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} ____cacheline_aligned_in_smp;
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/*
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* Spinlock protecting the tables - not taken during lookup:
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*/
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static DEFINE_SPINLOCK(table_lock);
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/*
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* Per-CPU lookup locks for fast hash lookup:
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*/
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static DEFINE_PER_CPU(spinlock_t, lookup_lock);
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/*
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* Mutex to serialize state changes with show-stats activities:
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*/
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static DEFINE_MUTEX(show_mutex);
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/*
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* Collection status, active/inactive:
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*/
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static int __read_mostly active;
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/*
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* Beginning/end timestamps of measurement:
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*/
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static ktime_t time_start, time_stop;
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/*
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* tstat entry structs only get allocated while collection is
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* active and never freed during that time - this simplifies
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* things quite a bit.
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*
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* They get freed when a new collection period is started.
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*/
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#define MAX_ENTRIES_BITS 10
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#define MAX_ENTRIES (1UL << MAX_ENTRIES_BITS)
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static unsigned long nr_entries;
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static struct entry entries[MAX_ENTRIES];
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static atomic_t overflow_count;
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static void reset_entries(void)
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{
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nr_entries = 0;
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memset(entries, 0, sizeof(entries));
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atomic_set(&overflow_count, 0);
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}
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static struct entry *alloc_entry(void)
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{
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if (nr_entries >= MAX_ENTRIES)
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return NULL;
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return entries + nr_entries++;
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}
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/*
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* The entries are in a hash-table, for fast lookup:
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*/
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#define TSTAT_HASH_BITS (MAX_ENTRIES_BITS - 1)
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#define TSTAT_HASH_SIZE (1UL << TSTAT_HASH_BITS)
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#define TSTAT_HASH_MASK (TSTAT_HASH_SIZE - 1)
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#define __tstat_hashfn(entry) \
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(((unsigned long)(entry)->timer ^ \
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(unsigned long)(entry)->start_func ^ \
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(unsigned long)(entry)->expire_func ^ \
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(unsigned long)(entry)->pid ) & TSTAT_HASH_MASK)
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#define tstat_hashentry(entry) (tstat_hash_table + __tstat_hashfn(entry))
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|
||||
static struct entry *tstat_hash_table[TSTAT_HASH_SIZE] __read_mostly;
|
||||
|
||||
static int match_entries(struct entry *entry1, struct entry *entry2)
|
||||
{
|
||||
return entry1->timer == entry2->timer &&
|
||||
entry1->start_func == entry2->start_func &&
|
||||
entry1->expire_func == entry2->expire_func &&
|
||||
entry1->pid == entry2->pid;
|
||||
}
|
||||
|
||||
/*
|
||||
* Look up whether an entry matching this item is present
|
||||
* in the hash already. Must be called with irqs off and the
|
||||
* lookup lock held:
|
||||
*/
|
||||
static struct entry *tstat_lookup(struct entry *entry, char *comm)
|
||||
{
|
||||
struct entry **head, *curr, *prev;
|
||||
|
||||
head = tstat_hashentry(entry);
|
||||
curr = *head;
|
||||
|
||||
/*
|
||||
* The fastpath is when the entry is already hashed,
|
||||
* we do this with the lookup lock held, but with the
|
||||
* table lock not held:
|
||||
*/
|
||||
while (curr) {
|
||||
if (match_entries(curr, entry))
|
||||
return curr;
|
||||
|
||||
curr = curr->next;
|
||||
}
|
||||
/*
|
||||
* Slowpath: allocate, set up and link a new hash entry:
|
||||
*/
|
||||
prev = NULL;
|
||||
curr = *head;
|
||||
|
||||
spin_lock(&table_lock);
|
||||
/*
|
||||
* Make sure we have not raced with another CPU:
|
||||
*/
|
||||
while (curr) {
|
||||
if (match_entries(curr, entry))
|
||||
goto out_unlock;
|
||||
|
||||
prev = curr;
|
||||
curr = curr->next;
|
||||
}
|
||||
|
||||
curr = alloc_entry();
|
||||
if (curr) {
|
||||
*curr = *entry;
|
||||
curr->count = 0;
|
||||
memcpy(curr->comm, comm, TASK_COMM_LEN);
|
||||
if (prev)
|
||||
prev->next = curr;
|
||||
else
|
||||
*head = curr;
|
||||
curr->next = NULL;
|
||||
}
|
||||
out_unlock:
|
||||
spin_unlock(&table_lock);
|
||||
|
||||
return curr;
|
||||
}
|
||||
|
||||
/**
|
||||
* timer_stats_update_stats - Update the statistics for a timer.
|
||||
* @timer: pointer to either a timer_list or a hrtimer
|
||||
* @pid: the pid of the task which set up the timer
|
||||
* @startf: pointer to the function which did the timer setup
|
||||
* @timerf: pointer to the timer callback function of the timer
|
||||
* @comm: name of the process which set up the timer
|
||||
*
|
||||
* When the timer is already registered, then the event counter is
|
||||
* incremented. Otherwise the timer is registered in a free slot.
|
||||
*/
|
||||
void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
|
||||
void *timerf, char * comm)
|
||||
{
|
||||
/*
|
||||
* It doesnt matter which lock we take:
|
||||
*/
|
||||
spinlock_t *lock = &per_cpu(lookup_lock, raw_smp_processor_id());
|
||||
struct entry *entry, input;
|
||||
unsigned long flags;
|
||||
|
||||
input.timer = timer;
|
||||
input.start_func = startf;
|
||||
input.expire_func = timerf;
|
||||
input.pid = pid;
|
||||
|
||||
spin_lock_irqsave(lock, flags);
|
||||
if (!active)
|
||||
goto out_unlock;
|
||||
|
||||
entry = tstat_lookup(&input, comm);
|
||||
if (likely(entry))
|
||||
entry->count++;
|
||||
else
|
||||
atomic_inc(&overflow_count);
|
||||
|
||||
out_unlock:
|
||||
spin_unlock_irqrestore(lock, flags);
|
||||
}
|
||||
|
||||
static void print_name_offset(struct seq_file *m, unsigned long addr)
|
||||
{
|
||||
char namebuf[KSYM_NAME_LEN+1];
|
||||
unsigned long size, offset;
|
||||
const char *sym_name;
|
||||
char *modname;
|
||||
|
||||
sym_name = kallsyms_lookup(addr, &size, &offset, &modname, namebuf);
|
||||
if (sym_name)
|
||||
seq_printf(m, "%s", sym_name);
|
||||
else
|
||||
seq_printf(m, "<%p>", (void *)addr);
|
||||
}
|
||||
|
||||
static int tstats_show(struct seq_file *m, void *v)
|
||||
{
|
||||
struct timespec period;
|
||||
struct entry *entry;
|
||||
unsigned long ms;
|
||||
long events = 0;
|
||||
ktime_t time;
|
||||
int i;
|
||||
|
||||
mutex_lock(&show_mutex);
|
||||
/*
|
||||
* If still active then calculate up to now:
|
||||
*/
|
||||
if (active)
|
||||
time_stop = ktime_get();
|
||||
|
||||
time = ktime_sub(time_stop, time_start);
|
||||
|
||||
period = ktime_to_timespec(time);
|
||||
ms = period.tv_nsec / 1000000;
|
||||
|
||||
seq_puts(m, "Timer Stats Version: v0.1\n");
|
||||
seq_printf(m, "Sample period: %ld.%03ld s\n", period.tv_sec, ms);
|
||||
if (atomic_read(&overflow_count))
|
||||
seq_printf(m, "Overflow: %d entries\n",
|
||||
atomic_read(&overflow_count));
|
||||
|
||||
for (i = 0; i < nr_entries; i++) {
|
||||
entry = entries + i;
|
||||
seq_printf(m, "%4lu, %5d %-16s ",
|
||||
entry->count, entry->pid, entry->comm);
|
||||
|
||||
print_name_offset(m, (unsigned long)entry->start_func);
|
||||
seq_puts(m, " (");
|
||||
print_name_offset(m, (unsigned long)entry->expire_func);
|
||||
seq_puts(m, ")\n");
|
||||
|
||||
events += entry->count;
|
||||
}
|
||||
|
||||
ms += period.tv_sec * 1000;
|
||||
if (!ms)
|
||||
ms = 1;
|
||||
|
||||
if (events && period.tv_sec)
|
||||
seq_printf(m, "%ld total events, %ld.%ld events/sec\n", events,
|
||||
events / period.tv_sec, events * 1000 / ms);
|
||||
else
|
||||
seq_printf(m, "%ld total events\n", events);
|
||||
|
||||
mutex_unlock(&show_mutex);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* After a state change, make sure all concurrent lookup/update
|
||||
* activities have stopped:
|
||||
*/
|
||||
static void sync_access(void)
|
||||
{
|
||||
unsigned long flags;
|
||||
int cpu;
|
||||
|
||||
for_each_online_cpu(cpu) {
|
||||
spin_lock_irqsave(&per_cpu(lookup_lock, cpu), flags);
|
||||
/* nothing */
|
||||
spin_unlock_irqrestore(&per_cpu(lookup_lock, cpu), flags);
|
||||
}
|
||||
}
|
||||
|
||||
static ssize_t tstats_write(struct file *file, const char __user *buf,
|
||||
size_t count, loff_t *offs)
|
||||
{
|
||||
char ctl[2];
|
||||
|
||||
if (count != 2 || *offs)
|
||||
return -EINVAL;
|
||||
|
||||
if (copy_from_user(ctl, buf, count))
|
||||
return -EFAULT;
|
||||
|
||||
mutex_lock(&show_mutex);
|
||||
switch (ctl[0]) {
|
||||
case '0':
|
||||
if (active) {
|
||||
active = 0;
|
||||
time_stop = ktime_get();
|
||||
sync_access();
|
||||
}
|
||||
break;
|
||||
case '1':
|
||||
if (!active) {
|
||||
reset_entries();
|
||||
time_start = ktime_get();
|
||||
active = 1;
|
||||
}
|
||||
break;
|
||||
default:
|
||||
count = -EINVAL;
|
||||
}
|
||||
mutex_unlock(&show_mutex);
|
||||
|
||||
return count;
|
||||
}
|
||||
|
||||
static int tstats_open(struct inode *inode, struct file *filp)
|
||||
{
|
||||
return single_open(filp, tstats_show, NULL);
|
||||
}
|
||||
|
||||
static struct file_operations tstats_fops = {
|
||||
.open = tstats_open,
|
||||
.read = seq_read,
|
||||
.write = tstats_write,
|
||||
.llseek = seq_lseek,
|
||||
.release = seq_release,
|
||||
};
|
||||
|
||||
void __init init_timer_stats(void)
|
||||
{
|
||||
int cpu;
|
||||
|
||||
for_each_possible_cpu(cpu)
|
||||
spin_lock_init(&per_cpu(lookup_lock, cpu));
|
||||
}
|
||||
|
||||
static int __init init_tstats_procfs(void)
|
||||
{
|
||||
struct proc_dir_entry *pe;
|
||||
|
||||
pe = create_proc_entry("timer_stats", 0644, NULL);
|
||||
if (!pe)
|
||||
return -ENOMEM;
|
||||
|
||||
pe->proc_fops = &tstats_fops;
|
||||
|
||||
return 0;
|
||||
}
|
||||
__initcall(init_tstats_procfs);
|
||||
|
|
@ -35,6 +35,7 @@
|
|||
#include <linux/syscalls.h>
|
||||
#include <linux/delay.h>
|
||||
#include <linux/tick.h>
|
||||
#include <linux/kallsyms.h>
|
||||
|
||||
#include <asm/uaccess.h>
|
||||
#include <asm/unistd.h>
|
||||
|
|
@ -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);
|
||||
|
|
|
|||
|
|
@ -218,7 +218,7 @@ int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work)
|
|||
}
|
||||
EXPORT_SYMBOL_GPL(queue_work);
|
||||
|
||||
static void delayed_work_timer_fn(unsigned long __data)
|
||||
void delayed_work_timer_fn(unsigned long __data)
|
||||
{
|
||||
struct delayed_work *dwork = (struct delayed_work *)__data;
|
||||
struct workqueue_struct *wq = get_wq_data(&dwork->work);
|
||||
|
|
@ -245,6 +245,7 @@ int fastcall queue_delayed_work(struct workqueue_struct *wq,
|
|||
struct timer_list *timer = &dwork->timer;
|
||||
struct work_struct *work = &dwork->work;
|
||||
|
||||
timer_stats_timer_set_start_info(timer);
|
||||
if (delay == 0)
|
||||
return queue_work(wq, work);
|
||||
|
||||
|
|
@ -593,8 +594,10 @@ EXPORT_SYMBOL(schedule_work);
|
|||
* After waiting for a given time this puts a job in the kernel-global
|
||||
* workqueue.
|
||||
*/
|
||||
int fastcall schedule_delayed_work(struct delayed_work *dwork, unsigned long delay)
|
||||
int fastcall schedule_delayed_work(struct delayed_work *dwork,
|
||||
unsigned long delay)
|
||||
{
|
||||
timer_stats_timer_set_start_info(&dwork->timer);
|
||||
return queue_delayed_work(keventd_wq, dwork, delay);
|
||||
}
|
||||
EXPORT_SYMBOL(schedule_delayed_work);
|
||||
|
|
|
|||
|
|
@ -134,6 +134,17 @@ config SCHEDSTATS
|
|||
application, you can say N to avoid the very slight overhead
|
||||
this adds.
|
||||
|
||||
config TIMER_STATS
|
||||
bool "Collect kernel timers statistics"
|
||||
depends on DEBUG_KERNEL && PROC_FS
|
||||
help
|
||||
If you say Y here, additional code will be inserted into the
|
||||
timer routines to collect statistics about kernel timers being
|
||||
reprogrammed. The statistics can be read from /proc/timer_stats.
|
||||
The statistics collection is started by writing 1 to /proc/timer_stats,
|
||||
writing 0 stops it. This feature is useful to collect information
|
||||
about timer usage patterns in kernel and userspace.
|
||||
|
||||
config DEBUG_SLAB
|
||||
bool "Debug slab memory allocations"
|
||||
depends on DEBUG_KERNEL && SLAB
|
||||
|
|
|
|||
Loading…
Reference in a new issue