2005-04-16 22:20:36 +00:00
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#ifndef _LINUX_TIMER_H
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#define _LINUX_TIMER_H
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#include <linux/list.h>
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[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>
2007-02-16 09:28:13 +00:00
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#include <linux/ktime.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/stddef.h>
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2008-04-30 07:55:03 +00:00
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#include <linux/debugobjects.h>
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2009-01-29 15:03:20 +00:00
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#include <linux/stringify.h>
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2005-04-16 22:20:36 +00:00
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2008-01-30 12:30:00 +00:00
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struct tvec_base;
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2005-04-16 22:20:36 +00:00
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struct timer_list {
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2010-03-11 22:04:36 +00:00
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/*
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* All fields that change during normal runtime grouped to the
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* same cacheline
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*/
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2005-04-16 22:20:36 +00:00
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struct list_head entry;
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unsigned long expires;
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2010-03-11 22:04:36 +00:00
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struct tvec_base *base;
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2005-04-16 22:20:36 +00:00
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void (*function)(unsigned long);
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unsigned long data;
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2010-03-11 22:04:36 +00:00
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int slack;
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[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>
2007-02-16 09:28:13 +00:00
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#ifdef CONFIG_TIMER_STATS
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2010-10-20 22:57:30 +00:00
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int start_pid;
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[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>
2007-02-16 09:28:13 +00:00
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void *start_site;
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char start_comm[16];
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#endif
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2009-01-29 15:03:20 +00:00
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#ifdef CONFIG_LOCKDEP
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struct lockdep_map lockdep_map;
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#endif
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2005-04-16 22:20:36 +00:00
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};
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2008-01-30 12:30:00 +00:00
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extern struct tvec_base boot_tvec_bases;
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[PATCH] timers fixes/improvements
This patch tries to solve following problems:
1. del_timer_sync() is racy. The timer can be fired again after
del_timer_sync have checked all cpus and before it will recheck
timer_pending().
2. It has scalability problems. All cpus are scanned to determine
if the timer is running on that cpu.
With this patch del_timer_sync is O(1) and no slower than plain
del_timer(pending_timer), unless it has to actually wait for
completion of the currently running timer.
The only restriction is that the recurring timer should not use
add_timer_on().
3. The timers are not serialized wrt to itself.
If CPU_0 does mod_timer(jiffies+1) while the timer is currently
running on CPU 1, it is quite possible that local interrupt on
CPU_0 will start that timer before it finished on CPU_1.
4. The timers locking is suboptimal. __mod_timer() takes 3 locks
at once and still requires wmb() in del_timer/run_timers.
The new implementation takes 2 locks sequentially and does not
need memory barriers.
Currently ->base != NULL means that the timer is pending. In that case
->base.lock is used to lock the timer. __mod_timer also takes timer->lock
because ->base can be == NULL.
This patch uses timer->entry.next != NULL as indication that the timer is
pending. So it does __list_del(), entry->next = NULL instead of list_del()
when the timer is deleted.
The ->base field is used for hashed locking only, it is initialized
in init_timer() which sets ->base = per_cpu(tvec_bases). When the
tvec_bases.lock is locked, it means that all timers which are tied
to this base via timer->base are locked, and the base itself is locked
too.
So __run_timers/migrate_timers can safely modify all timers which could
be found on ->tvX lists (pending timers).
When the timer's base is locked, and the timer removed from ->entry list
(which means that _run_timers/migrate_timers can't see this timer), it is
possible to set timer->base = NULL and drop the lock: the timer remains
locked.
This patch adds lock_timer_base() helper, which waits for ->base != NULL,
locks the ->base, and checks it is still the same.
__mod_timer() schedules the timer on the local CPU and changes it's base.
However, it does not lock both old and new bases at once. It locks the
timer via lock_timer_base(), deletes the timer, sets ->base = NULL, and
unlocks old base. Then __mod_timer() locks new_base, sets ->base = new_base,
and adds this timer. This simplifies the code, because AB-BA deadlock is not
possible. __mod_timer() also ensures that the timer's base is not changed
while the timer's handler is running on the old base.
__run_timers(), del_timer() do not change ->base anymore, they only clear
pending flag.
So del_timer_sync() can test timer->base->running_timer == timer to detect
whether it is running or not.
We don't need timer_list->lock anymore, this patch kills it.
We also don't need barriers. del_timer() and __run_timers() used smp_wmb()
before clearing timer's pending flag. It was needed because __mod_timer()
did not lock old_base if the timer is not pending, so __mod_timer()->list_add()
could race with del_timer()->list_del(). With this patch these functions are
serialized through base->lock.
One problem. TIMER_INITIALIZER can't use per_cpu(tvec_bases). So this patch
adds global
struct timer_base_s {
spinlock_t lock;
struct timer_list *running_timer;
} __init_timer_base;
which is used by TIMER_INITIALIZER. The corresponding fields in tvec_t_base_s
struct are replaced by struct timer_base_s t_base.
It is indeed ugly. But this can't have scalability problems. The global
__init_timer_base.lock is used only when __mod_timer() is called for the first
time AND the timer was compile time initialized. After that the timer migrates
to the local CPU.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Renaud Lienhart <renaud.lienhart@free.fr>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 07:08:56 +00:00
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2009-01-29 15:03:20 +00:00
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#ifdef CONFIG_LOCKDEP
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/*
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* NB: because we have to copy the lockdep_map, setting the lockdep_map key
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* (second argument) here is required, otherwise it could be initialised to
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* the copy of the lockdep_map later! We use the pointer to and the string
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* "<file>:<line>" as the key resp. the name of the lockdep_map.
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*/
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#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn) \
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.lockdep_map = STATIC_LOCKDEP_MAP_INIT(_kn, &_kn),
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#else
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#define __TIMER_LOCKDEP_MAP_INITIALIZER(_kn)
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#endif
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2010-10-20 22:57:33 +00:00
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/*
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* Note that all tvec_bases are 2 byte aligned and lower bit of
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* base in timer_list is guaranteed to be zero. Use the LSB to
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* indicate whether the timer is deferrable.
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*
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* A deferrable timer will work normally when the system is busy, but
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* will not cause a CPU to come out of idle just to service it; instead,
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* the timer will be serviced when the CPU eventually wakes up with a
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* subsequent non-deferrable timer.
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*/
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#define TBASE_DEFERRABLE_FLAG (0x1)
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2005-04-16 22:20:36 +00:00
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#define TIMER_INITIALIZER(_function, _expires, _data) { \
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2008-04-30 07:55:03 +00:00
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.entry = { .prev = TIMER_ENTRY_STATIC }, \
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2005-04-16 22:20:36 +00:00
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.function = (_function), \
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.expires = (_expires), \
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.data = (_data), \
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2006-03-31 10:30:30 +00:00
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.base = &boot_tvec_bases, \
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2010-10-20 22:57:30 +00:00
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.slack = -1, \
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2009-01-29 15:03:20 +00:00
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__TIMER_LOCKDEP_MAP_INITIALIZER( \
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__FILE__ ":" __stringify(__LINE__)) \
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2005-04-16 22:20:36 +00:00
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}
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2010-10-20 22:57:33 +00:00
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#define TBASE_MAKE_DEFERRED(ptr) ((struct tvec_base *) \
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((unsigned char *)(ptr) + TBASE_DEFERRABLE_FLAG))
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#define TIMER_DEFERRED_INITIALIZER(_function, _expires, _data) {\
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.entry = { .prev = TIMER_ENTRY_STATIC }, \
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.function = (_function), \
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.expires = (_expires), \
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.data = (_data), \
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.base = TBASE_MAKE_DEFERRED(&boot_tvec_bases), \
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__TIMER_LOCKDEP_MAP_INITIALIZER( \
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__FILE__ ":" __stringify(__LINE__)) \
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}
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2005-09-09 20:10:40 +00:00
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#define DEFINE_TIMER(_name, _function, _expires, _data) \
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struct timer_list _name = \
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TIMER_INITIALIZER(_function, _expires, _data)
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2009-01-29 15:03:20 +00:00
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void init_timer_key(struct timer_list *timer,
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const char *name,
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struct lock_class_key *key);
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void init_timer_deferrable_key(struct timer_list *timer,
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const char *name,
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struct lock_class_key *key);
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#ifdef CONFIG_LOCKDEP
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#define init_timer(timer) \
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do { \
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static struct lock_class_key __key; \
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init_timer_key((timer), #timer, &__key); \
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} while (0)
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#define init_timer_deferrable(timer) \
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do { \
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static struct lock_class_key __key; \
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init_timer_deferrable_key((timer), #timer, &__key); \
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} while (0)
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#define init_timer_on_stack(timer) \
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do { \
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static struct lock_class_key __key; \
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init_timer_on_stack_key((timer), #timer, &__key); \
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} while (0)
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#define setup_timer(timer, fn, data) \
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do { \
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static struct lock_class_key __key; \
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setup_timer_key((timer), #timer, &__key, (fn), (data));\
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} while (0)
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#define setup_timer_on_stack(timer, fn, data) \
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do { \
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static struct lock_class_key __key; \
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setup_timer_on_stack_key((timer), #timer, &__key, \
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(fn), (data)); \
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} while (0)
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2010-05-10 21:26:20 +00:00
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#define setup_deferrable_timer_on_stack(timer, fn, data) \
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do { \
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static struct lock_class_key __key; \
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setup_deferrable_timer_on_stack_key((timer), #timer, \
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&__key, (fn), \
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(data)); \
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} while (0)
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2009-01-29 15:03:20 +00:00
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#else
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#define init_timer(timer)\
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init_timer_key((timer), NULL, NULL)
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#define init_timer_deferrable(timer)\
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init_timer_deferrable_key((timer), NULL, NULL)
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#define init_timer_on_stack(timer)\
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init_timer_on_stack_key((timer), NULL, NULL)
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#define setup_timer(timer, fn, data)\
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setup_timer_key((timer), NULL, NULL, (fn), (data))
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#define setup_timer_on_stack(timer, fn, data)\
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setup_timer_on_stack_key((timer), NULL, NULL, (fn), (data))
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2010-05-10 21:26:20 +00:00
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#define setup_deferrable_timer_on_stack(timer, fn, data)\
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setup_deferrable_timer_on_stack_key((timer), NULL, NULL, (fn), (data))
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2009-01-29 15:03:20 +00:00
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#endif
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2005-04-16 22:20:36 +00:00
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2008-04-30 07:55:03 +00:00
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#ifdef CONFIG_DEBUG_OBJECTS_TIMERS
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2009-01-29 15:03:20 +00:00
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extern void init_timer_on_stack_key(struct timer_list *timer,
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const char *name,
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struct lock_class_key *key);
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2008-04-30 07:55:03 +00:00
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extern void destroy_timer_on_stack(struct timer_list *timer);
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#else
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static inline void destroy_timer_on_stack(struct timer_list *timer) { }
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2009-01-29 15:03:20 +00:00
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static inline void init_timer_on_stack_key(struct timer_list *timer,
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const char *name,
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struct lock_class_key *key)
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2008-04-30 07:55:03 +00:00
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{
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2009-01-29 15:03:20 +00:00
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init_timer_key(timer, name, key);
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2008-04-30 07:55:03 +00:00
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}
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#endif
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2009-01-29 15:03:20 +00:00
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static inline void setup_timer_key(struct timer_list * timer,
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const char *name,
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struct lock_class_key *key,
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2005-10-30 23:01:38 +00:00
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void (*function)(unsigned long),
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unsigned long data)
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{
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timer->function = function;
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timer->data = data;
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2009-01-29 15:03:20 +00:00
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init_timer_key(timer, name, key);
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2005-10-30 23:01:38 +00:00
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}
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2009-01-29 15:03:20 +00:00
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static inline void setup_timer_on_stack_key(struct timer_list *timer,
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const char *name,
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struct lock_class_key *key,
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2008-04-30 07:55:03 +00:00
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void (*function)(unsigned long),
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unsigned long data)
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{
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timer->function = function;
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timer->data = data;
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2009-01-29 15:03:20 +00:00
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init_timer_on_stack_key(timer, name, key);
|
2008-04-30 07:55:03 +00:00
|
|
|
}
|
|
|
|
|
2010-05-10 21:26:20 +00:00
|
|
|
extern void setup_deferrable_timer_on_stack_key(struct timer_list *timer,
|
|
|
|
const char *name,
|
|
|
|
struct lock_class_key *key,
|
|
|
|
void (*function)(unsigned long),
|
|
|
|
unsigned long data);
|
|
|
|
|
2007-01-26 08:57:09 +00:00
|
|
|
/**
|
2005-04-16 22:20:36 +00:00
|
|
|
* timer_pending - is a timer pending?
|
|
|
|
* @timer: the timer in question
|
|
|
|
*
|
|
|
|
* timer_pending will tell whether a given timer is currently pending,
|
|
|
|
* or not. Callers must ensure serialization wrt. other operations done
|
|
|
|
* to this timer, eg. interrupt contexts, or other CPUs on SMP.
|
|
|
|
*
|
|
|
|
* return value: 1 if the timer is pending, 0 if not.
|
|
|
|
*/
|
|
|
|
static inline int timer_pending(const struct timer_list * timer)
|
|
|
|
{
|
[PATCH] timers fixes/improvements
This patch tries to solve following problems:
1. del_timer_sync() is racy. The timer can be fired again after
del_timer_sync have checked all cpus and before it will recheck
timer_pending().
2. It has scalability problems. All cpus are scanned to determine
if the timer is running on that cpu.
With this patch del_timer_sync is O(1) and no slower than plain
del_timer(pending_timer), unless it has to actually wait for
completion of the currently running timer.
The only restriction is that the recurring timer should not use
add_timer_on().
3. The timers are not serialized wrt to itself.
If CPU_0 does mod_timer(jiffies+1) while the timer is currently
running on CPU 1, it is quite possible that local interrupt on
CPU_0 will start that timer before it finished on CPU_1.
4. The timers locking is suboptimal. __mod_timer() takes 3 locks
at once and still requires wmb() in del_timer/run_timers.
The new implementation takes 2 locks sequentially and does not
need memory barriers.
Currently ->base != NULL means that the timer is pending. In that case
->base.lock is used to lock the timer. __mod_timer also takes timer->lock
because ->base can be == NULL.
This patch uses timer->entry.next != NULL as indication that the timer is
pending. So it does __list_del(), entry->next = NULL instead of list_del()
when the timer is deleted.
The ->base field is used for hashed locking only, it is initialized
in init_timer() which sets ->base = per_cpu(tvec_bases). When the
tvec_bases.lock is locked, it means that all timers which are tied
to this base via timer->base are locked, and the base itself is locked
too.
So __run_timers/migrate_timers can safely modify all timers which could
be found on ->tvX lists (pending timers).
When the timer's base is locked, and the timer removed from ->entry list
(which means that _run_timers/migrate_timers can't see this timer), it is
possible to set timer->base = NULL and drop the lock: the timer remains
locked.
This patch adds lock_timer_base() helper, which waits for ->base != NULL,
locks the ->base, and checks it is still the same.
__mod_timer() schedules the timer on the local CPU and changes it's base.
However, it does not lock both old and new bases at once. It locks the
timer via lock_timer_base(), deletes the timer, sets ->base = NULL, and
unlocks old base. Then __mod_timer() locks new_base, sets ->base = new_base,
and adds this timer. This simplifies the code, because AB-BA deadlock is not
possible. __mod_timer() also ensures that the timer's base is not changed
while the timer's handler is running on the old base.
__run_timers(), del_timer() do not change ->base anymore, they only clear
pending flag.
So del_timer_sync() can test timer->base->running_timer == timer to detect
whether it is running or not.
We don't need timer_list->lock anymore, this patch kills it.
We also don't need barriers. del_timer() and __run_timers() used smp_wmb()
before clearing timer's pending flag. It was needed because __mod_timer()
did not lock old_base if the timer is not pending, so __mod_timer()->list_add()
could race with del_timer()->list_del(). With this patch these functions are
serialized through base->lock.
One problem. TIMER_INITIALIZER can't use per_cpu(tvec_bases). So this patch
adds global
struct timer_base_s {
spinlock_t lock;
struct timer_list *running_timer;
} __init_timer_base;
which is used by TIMER_INITIALIZER. The corresponding fields in tvec_t_base_s
struct are replaced by struct timer_base_s t_base.
It is indeed ugly. But this can't have scalability problems. The global
__init_timer_base.lock is used only when __mod_timer() is called for the first
time AND the timer was compile time initialized. After that the timer migrates
to the local CPU.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Renaud Lienhart <renaud.lienhart@free.fr>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 07:08:56 +00:00
|
|
|
return timer->entry.next != NULL;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
extern void add_timer_on(struct timer_list *timer, int cpu);
|
|
|
|
extern int del_timer(struct timer_list * timer);
|
|
|
|
extern int mod_timer(struct timer_list *timer, unsigned long expires);
|
2009-02-18 11:23:29 +00:00
|
|
|
extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
|
2009-04-16 06:43:26 +00:00
|
|
|
extern int mod_timer_pinned(struct timer_list *timer, unsigned long expires);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2010-03-11 22:04:36 +00:00
|
|
|
extern void set_timer_slack(struct timer_list *time, int slack_hz);
|
|
|
|
|
2009-04-16 06:43:26 +00:00
|
|
|
#define TIMER_NOT_PINNED 0
|
|
|
|
#define TIMER_PINNED 1
|
2007-05-29 21:47:39 +00:00
|
|
|
/*
|
|
|
|
* The jiffies value which is added to now, when there is no timer
|
|
|
|
* in the timer wheel:
|
|
|
|
*/
|
|
|
|
#define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1)
|
|
|
|
|
2007-02-16 09:27:47 +00:00
|
|
|
/*
|
|
|
|
* Return when the next timer-wheel timeout occurs (in absolute jiffies),
|
|
|
|
* locks the timer base and does the comparison against the given
|
|
|
|
* jiffie.
|
|
|
|
*/
|
|
|
|
extern unsigned long get_next_timer_interrupt(unsigned long now);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
[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>
2007-02-16 09:28:13 +00:00
|
|
|
/*
|
|
|
|
* Timer-statistics info:
|
|
|
|
*/
|
|
|
|
#ifdef CONFIG_TIMER_STATS
|
|
|
|
|
2009-06-23 15:38:15 +00:00
|
|
|
extern int timer_stats_active;
|
|
|
|
|
2007-07-16 06:40:30 +00:00
|
|
|
#define TIMER_STATS_FLAG_DEFERRABLE 0x1
|
|
|
|
|
[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>
2007-02-16 09:28:13 +00:00
|
|
|
extern void init_timer_stats(void);
|
|
|
|
|
|
|
|
extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
|
2007-07-16 06:40:30 +00:00
|
|
|
void *timerf, char *comm,
|
|
|
|
unsigned int timer_flag);
|
[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>
2007-02-16 09:28:13 +00:00
|
|
|
|
|
|
|
extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
|
|
|
|
void *addr);
|
|
|
|
|
|
|
|
static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
|
|
|
|
{
|
2009-06-23 15:38:15 +00:00
|
|
|
if (likely(!timer_stats_active))
|
|
|
|
return;
|
[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>
2007-02-16 09:28:13 +00:00
|
|
|
__timer_stats_timer_set_start_info(timer, __builtin_return_address(0));
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
|
|
|
|
{
|
|
|
|
timer->start_site = NULL;
|
|
|
|
}
|
|
|
|
#else
|
|
|
|
static inline void init_timer_stats(void)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
2009-02-18 11:23:29 +00:00
|
|
|
extern void add_timer(struct timer_list *timer);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2010-10-20 22:57:31 +00:00
|
|
|
extern int try_to_del_timer_sync(struct timer_list *timer);
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
extern int del_timer_sync(struct timer_list *timer);
|
|
|
|
#else
|
2005-06-23 07:08:59 +00:00
|
|
|
# define del_timer_sync(t) del_timer(t)
|
2005-04-16 22:20:36 +00:00
|
|
|
#endif
|
|
|
|
|
[PATCH] timers fixes/improvements
This patch tries to solve following problems:
1. del_timer_sync() is racy. The timer can be fired again after
del_timer_sync have checked all cpus and before it will recheck
timer_pending().
2. It has scalability problems. All cpus are scanned to determine
if the timer is running on that cpu.
With this patch del_timer_sync is O(1) and no slower than plain
del_timer(pending_timer), unless it has to actually wait for
completion of the currently running timer.
The only restriction is that the recurring timer should not use
add_timer_on().
3. The timers are not serialized wrt to itself.
If CPU_0 does mod_timer(jiffies+1) while the timer is currently
running on CPU 1, it is quite possible that local interrupt on
CPU_0 will start that timer before it finished on CPU_1.
4. The timers locking is suboptimal. __mod_timer() takes 3 locks
at once and still requires wmb() in del_timer/run_timers.
The new implementation takes 2 locks sequentially and does not
need memory barriers.
Currently ->base != NULL means that the timer is pending. In that case
->base.lock is used to lock the timer. __mod_timer also takes timer->lock
because ->base can be == NULL.
This patch uses timer->entry.next != NULL as indication that the timer is
pending. So it does __list_del(), entry->next = NULL instead of list_del()
when the timer is deleted.
The ->base field is used for hashed locking only, it is initialized
in init_timer() which sets ->base = per_cpu(tvec_bases). When the
tvec_bases.lock is locked, it means that all timers which are tied
to this base via timer->base are locked, and the base itself is locked
too.
So __run_timers/migrate_timers can safely modify all timers which could
be found on ->tvX lists (pending timers).
When the timer's base is locked, and the timer removed from ->entry list
(which means that _run_timers/migrate_timers can't see this timer), it is
possible to set timer->base = NULL and drop the lock: the timer remains
locked.
This patch adds lock_timer_base() helper, which waits for ->base != NULL,
locks the ->base, and checks it is still the same.
__mod_timer() schedules the timer on the local CPU and changes it's base.
However, it does not lock both old and new bases at once. It locks the
timer via lock_timer_base(), deletes the timer, sets ->base = NULL, and
unlocks old base. Then __mod_timer() locks new_base, sets ->base = new_base,
and adds this timer. This simplifies the code, because AB-BA deadlock is not
possible. __mod_timer() also ensures that the timer's base is not changed
while the timer's handler is running on the old base.
__run_timers(), del_timer() do not change ->base anymore, they only clear
pending flag.
So del_timer_sync() can test timer->base->running_timer == timer to detect
whether it is running or not.
We don't need timer_list->lock anymore, this patch kills it.
We also don't need barriers. del_timer() and __run_timers() used smp_wmb()
before clearing timer's pending flag. It was needed because __mod_timer()
did not lock old_base if the timer is not pending, so __mod_timer()->list_add()
could race with del_timer()->list_del(). With this patch these functions are
serialized through base->lock.
One problem. TIMER_INITIALIZER can't use per_cpu(tvec_bases). So this patch
adds global
struct timer_base_s {
spinlock_t lock;
struct timer_list *running_timer;
} __init_timer_base;
which is used by TIMER_INITIALIZER. The corresponding fields in tvec_t_base_s
struct are replaced by struct timer_base_s t_base.
It is indeed ugly. But this can't have scalability problems. The global
__init_timer_base.lock is used only when __mod_timer() is called for the first
time AND the timer was compile time initialized. After that the timer migrates
to the local CPU.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Renaud Lienhart <renaud.lienhart@free.fr>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-23 07:08:56 +00:00
|
|
|
#define del_singleshot_timer_sync(t) del_timer_sync(t)
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
extern void init_timers(void);
|
|
|
|
extern void run_local_timers(void);
|
2006-03-26 09:38:12 +00:00
|
|
|
struct hrtimer;
|
2007-02-16 09:27:49 +00:00
|
|
|
extern enum hrtimer_restart it_real_fn(struct hrtimer *);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2006-12-10 10:21:24 +00:00
|
|
|
unsigned long __round_jiffies(unsigned long j, int cpu);
|
|
|
|
unsigned long __round_jiffies_relative(unsigned long j, int cpu);
|
|
|
|
unsigned long round_jiffies(unsigned long j);
|
|
|
|
unsigned long round_jiffies_relative(unsigned long j);
|
|
|
|
|
2008-11-06 07:42:48 +00:00
|
|
|
unsigned long __round_jiffies_up(unsigned long j, int cpu);
|
|
|
|
unsigned long __round_jiffies_up_relative(unsigned long j, int cpu);
|
|
|
|
unsigned long round_jiffies_up(unsigned long j);
|
|
|
|
unsigned long round_jiffies_up_relative(unsigned long j);
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
#endif
|