2 * Performance counter core code
4 * Copyright(C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright(C) 2008 Red Hat, Inc., Ingo Molnar
7 * For licencing details see kernel-base/COPYING
11 #include <linux/cpu.h>
12 #include <linux/smp.h>
13 #include <linux/file.h>
14 #include <linux/poll.h>
15 #include <linux/sysfs.h>
16 #include <linux/ptrace.h>
17 #include <linux/percpu.h>
18 #include <linux/uaccess.h>
19 #include <linux/syscalls.h>
20 #include <linux/anon_inodes.h>
21 #include <linux/kernel_stat.h>
22 #include <linux/perf_counter.h>
24 #include <linux/vmstat.h>
25 #include <linux/rculist.h>
26 #include <linux/hardirq.h>
28 #include <asm/irq_regs.h>
31 * Each CPU has a list of per CPU counters:
33 DEFINE_PER_CPU(struct perf_cpu_context
, perf_cpu_context
);
35 int perf_max_counters __read_mostly
= 1;
36 static int perf_reserved_percpu __read_mostly
;
37 static int perf_overcommit __read_mostly
= 1;
40 * Mutex for (sysadmin-configurable) counter reservations:
42 static DEFINE_MUTEX(perf_resource_mutex
);
45 * Architecture provided APIs - weak aliases:
47 extern __weak
const struct hw_perf_counter_ops
*
48 hw_perf_counter_init(struct perf_counter
*counter
)
53 u64 __weak
hw_perf_save_disable(void) { return 0; }
54 void __weak
hw_perf_restore(u64 ctrl
) { barrier(); }
55 void __weak
hw_perf_counter_setup(int cpu
) { barrier(); }
56 int __weak
hw_perf_group_sched_in(struct perf_counter
*group_leader
,
57 struct perf_cpu_context
*cpuctx
,
58 struct perf_counter_context
*ctx
, int cpu
)
63 void __weak
perf_counter_print_debug(void) { }
66 list_add_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
68 struct perf_counter
*group_leader
= counter
->group_leader
;
71 * Depending on whether it is a standalone or sibling counter,
72 * add it straight to the context's counter list, or to the group
73 * leader's sibling list:
75 if (counter
->group_leader
== counter
)
76 list_add_tail(&counter
->list_entry
, &ctx
->counter_list
);
78 list_add_tail(&counter
->list_entry
, &group_leader
->sibling_list
);
80 list_add_rcu(&counter
->event_entry
, &ctx
->event_list
);
84 list_del_counter(struct perf_counter
*counter
, struct perf_counter_context
*ctx
)
86 struct perf_counter
*sibling
, *tmp
;
88 list_del_init(&counter
->list_entry
);
89 list_del_rcu(&counter
->event_entry
);
92 * If this was a group counter with sibling counters then
93 * upgrade the siblings to singleton counters by adding them
94 * to the context list directly:
96 list_for_each_entry_safe(sibling
, tmp
,
97 &counter
->sibling_list
, list_entry
) {
99 list_move_tail(&sibling
->list_entry
, &ctx
->counter_list
);
100 sibling
->group_leader
= sibling
;
105 counter_sched_out(struct perf_counter
*counter
,
106 struct perf_cpu_context
*cpuctx
,
107 struct perf_counter_context
*ctx
)
109 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
112 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
113 counter
->hw_ops
->disable(counter
);
116 if (!is_software_counter(counter
))
117 cpuctx
->active_oncpu
--;
119 if (counter
->hw_event
.exclusive
|| !cpuctx
->active_oncpu
)
120 cpuctx
->exclusive
= 0;
124 group_sched_out(struct perf_counter
*group_counter
,
125 struct perf_cpu_context
*cpuctx
,
126 struct perf_counter_context
*ctx
)
128 struct perf_counter
*counter
;
130 if (group_counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
133 counter_sched_out(group_counter
, cpuctx
, ctx
);
136 * Schedule out siblings (if any):
138 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
)
139 counter_sched_out(counter
, cpuctx
, ctx
);
141 if (group_counter
->hw_event
.exclusive
)
142 cpuctx
->exclusive
= 0;
146 * Cross CPU call to remove a performance counter
148 * We disable the counter on the hardware level first. After that we
149 * remove it from the context list.
151 static void __perf_counter_remove_from_context(void *info
)
153 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
154 struct perf_counter
*counter
= info
;
155 struct perf_counter_context
*ctx
= counter
->ctx
;
160 * If this is a task context, we need to check whether it is
161 * the current task context of this cpu. If not it has been
162 * scheduled out before the smp call arrived.
164 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
167 curr_rq_lock_irq_save(&flags
);
168 spin_lock(&ctx
->lock
);
170 counter_sched_out(counter
, cpuctx
, ctx
);
172 counter
->task
= NULL
;
176 * Protect the list operation against NMI by disabling the
177 * counters on a global level. NOP for non NMI based counters.
179 perf_flags
= hw_perf_save_disable();
180 list_del_counter(counter
, ctx
);
181 hw_perf_restore(perf_flags
);
185 * Allow more per task counters with respect to the
188 cpuctx
->max_pertask
=
189 min(perf_max_counters
- ctx
->nr_counters
,
190 perf_max_counters
- perf_reserved_percpu
);
193 spin_unlock(&ctx
->lock
);
194 curr_rq_unlock_irq_restore(&flags
);
199 * Remove the counter from a task's (or a CPU's) list of counters.
201 * Must be called with counter->mutex and ctx->mutex held.
203 * CPU counters are removed with a smp call. For task counters we only
204 * call when the task is on a CPU.
206 static void perf_counter_remove_from_context(struct perf_counter
*counter
)
208 struct perf_counter_context
*ctx
= counter
->ctx
;
209 struct task_struct
*task
= ctx
->task
;
213 * Per cpu counters are removed via an smp call and
214 * the removal is always sucessful.
216 smp_call_function_single(counter
->cpu
,
217 __perf_counter_remove_from_context
,
223 task_oncpu_function_call(task
, __perf_counter_remove_from_context
,
226 spin_lock_irq(&ctx
->lock
);
228 * If the context is active we need to retry the smp call.
230 if (ctx
->nr_active
&& !list_empty(&counter
->list_entry
)) {
231 spin_unlock_irq(&ctx
->lock
);
236 * The lock prevents that this context is scheduled in so we
237 * can remove the counter safely, if the call above did not
240 if (!list_empty(&counter
->list_entry
)) {
242 list_del_counter(counter
, ctx
);
243 counter
->task
= NULL
;
245 spin_unlock_irq(&ctx
->lock
);
249 * Cross CPU call to disable a performance counter
251 static void __perf_counter_disable(void *info
)
253 struct perf_counter
*counter
= info
;
254 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
255 struct perf_counter_context
*ctx
= counter
->ctx
;
259 * If this is a per-task counter, need to check whether this
260 * counter's task is the current task on this cpu.
262 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
265 curr_rq_lock_irq_save(&flags
);
266 spin_lock(&ctx
->lock
);
269 * If the counter is on, turn it off.
270 * If it is in error state, leave it in error state.
272 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
) {
273 if (counter
== counter
->group_leader
)
274 group_sched_out(counter
, cpuctx
, ctx
);
276 counter_sched_out(counter
, cpuctx
, ctx
);
277 counter
->state
= PERF_COUNTER_STATE_OFF
;
280 spin_unlock(&ctx
->lock
);
281 curr_rq_unlock_irq_restore(&flags
);
287 static void perf_counter_disable(struct perf_counter
*counter
)
289 struct perf_counter_context
*ctx
= counter
->ctx
;
290 struct task_struct
*task
= ctx
->task
;
294 * Disable the counter on the cpu that it's on
296 smp_call_function_single(counter
->cpu
, __perf_counter_disable
,
302 task_oncpu_function_call(task
, __perf_counter_disable
, counter
);
304 spin_lock_irq(&ctx
->lock
);
306 * If the counter is still active, we need to retry the cross-call.
308 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
309 spin_unlock_irq(&ctx
->lock
);
314 * Since we have the lock this context can't be scheduled
315 * in, so we can change the state safely.
317 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
)
318 counter
->state
= PERF_COUNTER_STATE_OFF
;
320 spin_unlock_irq(&ctx
->lock
);
324 * Disable a counter and all its children.
326 static void perf_counter_disable_family(struct perf_counter
*counter
)
328 struct perf_counter
*child
;
330 perf_counter_disable(counter
);
333 * Lock the mutex to protect the list of children
335 mutex_lock(&counter
->mutex
);
336 list_for_each_entry(child
, &counter
->child_list
, child_list
)
337 perf_counter_disable(child
);
338 mutex_unlock(&counter
->mutex
);
342 counter_sched_in(struct perf_counter
*counter
,
343 struct perf_cpu_context
*cpuctx
,
344 struct perf_counter_context
*ctx
,
347 if (counter
->state
<= PERF_COUNTER_STATE_OFF
)
350 counter
->state
= PERF_COUNTER_STATE_ACTIVE
;
351 counter
->oncpu
= cpu
; /* TODO: put 'cpu' into cpuctx->cpu */
353 * The new state must be visible before we turn it on in the hardware:
357 if (counter
->hw_ops
->enable(counter
)) {
358 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
363 if (!is_software_counter(counter
))
364 cpuctx
->active_oncpu
++;
367 if (counter
->hw_event
.exclusive
)
368 cpuctx
->exclusive
= 1;
374 * Return 1 for a group consisting entirely of software counters,
375 * 0 if the group contains any hardware counters.
377 static int is_software_only_group(struct perf_counter
*leader
)
379 struct perf_counter
*counter
;
381 if (!is_software_counter(leader
))
383 list_for_each_entry(counter
, &leader
->sibling_list
, list_entry
)
384 if (!is_software_counter(counter
))
390 * Work out whether we can put this counter group on the CPU now.
392 static int group_can_go_on(struct perf_counter
*counter
,
393 struct perf_cpu_context
*cpuctx
,
397 * Groups consisting entirely of software counters can always go on.
399 if (is_software_only_group(counter
))
402 * If an exclusive group is already on, no other hardware
403 * counters can go on.
405 if (cpuctx
->exclusive
)
408 * If this group is exclusive and there are already
409 * counters on the CPU, it can't go on.
411 if (counter
->hw_event
.exclusive
&& cpuctx
->active_oncpu
)
414 * Otherwise, try to add it if all previous groups were able
421 * Cross CPU call to install and enable a performance counter
423 static void __perf_install_in_context(void *info
)
425 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
426 struct perf_counter
*counter
= info
;
427 struct perf_counter_context
*ctx
= counter
->ctx
;
428 struct perf_counter
*leader
= counter
->group_leader
;
429 int cpu
= smp_processor_id();
435 * If this is a task context, we need to check whether it is
436 * the current task context of this cpu. If not it has been
437 * scheduled out before the smp call arrived.
439 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
442 curr_rq_lock_irq_save(&flags
);
443 spin_lock(&ctx
->lock
);
446 * Protect the list operation against NMI by disabling the
447 * counters on a global level. NOP for non NMI based counters.
449 perf_flags
= hw_perf_save_disable();
451 list_add_counter(counter
, ctx
);
453 counter
->prev_state
= PERF_COUNTER_STATE_OFF
;
456 * Don't put the counter on if it is disabled or if
457 * it is in a group and the group isn't on.
459 if (counter
->state
!= PERF_COUNTER_STATE_INACTIVE
||
460 (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
))
464 * An exclusive counter can't go on if there are already active
465 * hardware counters, and no hardware counter can go on if there
466 * is already an exclusive counter on.
468 if (!group_can_go_on(counter
, cpuctx
, 1))
471 err
= counter_sched_in(counter
, cpuctx
, ctx
, cpu
);
475 * This counter couldn't go on. If it is in a group
476 * then we have to pull the whole group off.
477 * If the counter group is pinned then put it in error state.
479 if (leader
!= counter
)
480 group_sched_out(leader
, cpuctx
, ctx
);
481 if (leader
->hw_event
.pinned
)
482 leader
->state
= PERF_COUNTER_STATE_ERROR
;
485 if (!err
&& !ctx
->task
&& cpuctx
->max_pertask
)
486 cpuctx
->max_pertask
--;
489 hw_perf_restore(perf_flags
);
491 spin_unlock(&ctx
->lock
);
492 curr_rq_unlock_irq_restore(&flags
);
496 * Attach a performance counter to a context
498 * First we add the counter to the list with the hardware enable bit
499 * in counter->hw_config cleared.
501 * If the counter is attached to a task which is on a CPU we use a smp
502 * call to enable it in the task context. The task might have been
503 * scheduled away, but we check this in the smp call again.
505 * Must be called with ctx->mutex held.
508 perf_install_in_context(struct perf_counter_context
*ctx
,
509 struct perf_counter
*counter
,
512 struct task_struct
*task
= ctx
->task
;
516 * Per cpu counters are installed via an smp call and
517 * the install is always sucessful.
519 smp_call_function_single(cpu
, __perf_install_in_context
,
524 counter
->task
= task
;
526 task_oncpu_function_call(task
, __perf_install_in_context
,
529 spin_lock_irq(&ctx
->lock
);
531 * we need to retry the smp call.
533 if (ctx
->is_active
&& list_empty(&counter
->list_entry
)) {
534 spin_unlock_irq(&ctx
->lock
);
539 * The lock prevents that this context is scheduled in so we
540 * can add the counter safely, if it the call above did not
543 if (list_empty(&counter
->list_entry
)) {
544 list_add_counter(counter
, ctx
);
547 spin_unlock_irq(&ctx
->lock
);
551 * Cross CPU call to enable a performance counter
553 static void __perf_counter_enable(void *info
)
555 struct perf_counter
*counter
= info
;
556 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
557 struct perf_counter_context
*ctx
= counter
->ctx
;
558 struct perf_counter
*leader
= counter
->group_leader
;
563 * If this is a per-task counter, need to check whether this
564 * counter's task is the current task on this cpu.
566 if (ctx
->task
&& cpuctx
->task_ctx
!= ctx
)
569 curr_rq_lock_irq_save(&flags
);
570 spin_lock(&ctx
->lock
);
572 counter
->prev_state
= counter
->state
;
573 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
575 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
578 * If the counter is in a group and isn't the group leader,
579 * then don't put it on unless the group is on.
581 if (leader
!= counter
&& leader
->state
!= PERF_COUNTER_STATE_ACTIVE
)
584 if (!group_can_go_on(counter
, cpuctx
, 1))
587 err
= counter_sched_in(counter
, cpuctx
, ctx
,
592 * If this counter can't go on and it's part of a
593 * group, then the whole group has to come off.
595 if (leader
!= counter
)
596 group_sched_out(leader
, cpuctx
, ctx
);
597 if (leader
->hw_event
.pinned
)
598 leader
->state
= PERF_COUNTER_STATE_ERROR
;
602 spin_unlock(&ctx
->lock
);
603 curr_rq_unlock_irq_restore(&flags
);
609 static void perf_counter_enable(struct perf_counter
*counter
)
611 struct perf_counter_context
*ctx
= counter
->ctx
;
612 struct task_struct
*task
= ctx
->task
;
616 * Enable the counter on the cpu that it's on
618 smp_call_function_single(counter
->cpu
, __perf_counter_enable
,
623 spin_lock_irq(&ctx
->lock
);
624 if (counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
628 * If the counter is in error state, clear that first.
629 * That way, if we see the counter in error state below, we
630 * know that it has gone back into error state, as distinct
631 * from the task having been scheduled away before the
632 * cross-call arrived.
634 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
635 counter
->state
= PERF_COUNTER_STATE_OFF
;
638 spin_unlock_irq(&ctx
->lock
);
639 task_oncpu_function_call(task
, __perf_counter_enable
, counter
);
641 spin_lock_irq(&ctx
->lock
);
644 * If the context is active and the counter is still off,
645 * we need to retry the cross-call.
647 if (ctx
->is_active
&& counter
->state
== PERF_COUNTER_STATE_OFF
)
651 * Since we have the lock this context can't be scheduled
652 * in, so we can change the state safely.
654 if (counter
->state
== PERF_COUNTER_STATE_OFF
)
655 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
657 spin_unlock_irq(&ctx
->lock
);
661 * Enable a counter and all its children.
663 static void perf_counter_enable_family(struct perf_counter
*counter
)
665 struct perf_counter
*child
;
667 perf_counter_enable(counter
);
670 * Lock the mutex to protect the list of children
672 mutex_lock(&counter
->mutex
);
673 list_for_each_entry(child
, &counter
->child_list
, child_list
)
674 perf_counter_enable(child
);
675 mutex_unlock(&counter
->mutex
);
678 void __perf_counter_sched_out(struct perf_counter_context
*ctx
,
679 struct perf_cpu_context
*cpuctx
)
681 struct perf_counter
*counter
;
684 spin_lock(&ctx
->lock
);
686 if (likely(!ctx
->nr_counters
))
689 flags
= hw_perf_save_disable();
690 if (ctx
->nr_active
) {
691 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
)
692 group_sched_out(counter
, cpuctx
, ctx
);
694 hw_perf_restore(flags
);
696 spin_unlock(&ctx
->lock
);
700 * Called from scheduler to remove the counters of the current task,
701 * with interrupts disabled.
703 * We stop each counter and update the counter value in counter->count.
705 * This does not protect us against NMI, but disable()
706 * sets the disabled bit in the control field of counter _before_
707 * accessing the counter control register. If a NMI hits, then it will
708 * not restart the counter.
710 void perf_counter_task_sched_out(struct task_struct
*task
, int cpu
)
712 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
713 struct perf_counter_context
*ctx
= &task
->perf_counter_ctx
;
714 struct pt_regs
*regs
;
716 if (likely(!cpuctx
->task_ctx
))
719 regs
= task_pt_regs(task
);
720 perf_swcounter_event(PERF_COUNT_CONTEXT_SWITCHES
, 1, 1, regs
);
721 __perf_counter_sched_out(ctx
, cpuctx
);
723 cpuctx
->task_ctx
= NULL
;
726 static void perf_counter_cpu_sched_out(struct perf_cpu_context
*cpuctx
)
728 __perf_counter_sched_out(&cpuctx
->ctx
, cpuctx
);
732 group_sched_in(struct perf_counter
*group_counter
,
733 struct perf_cpu_context
*cpuctx
,
734 struct perf_counter_context
*ctx
,
737 struct perf_counter
*counter
, *partial_group
;
740 if (group_counter
->state
== PERF_COUNTER_STATE_OFF
)
743 ret
= hw_perf_group_sched_in(group_counter
, cpuctx
, ctx
, cpu
);
745 return ret
< 0 ? ret
: 0;
747 group_counter
->prev_state
= group_counter
->state
;
748 if (counter_sched_in(group_counter
, cpuctx
, ctx
, cpu
))
752 * Schedule in siblings as one group (if any):
754 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
755 counter
->prev_state
= counter
->state
;
756 if (counter_sched_in(counter
, cpuctx
, ctx
, cpu
)) {
757 partial_group
= counter
;
766 * Groups can be scheduled in as one unit only, so undo any
767 * partial group before returning:
769 list_for_each_entry(counter
, &group_counter
->sibling_list
, list_entry
) {
770 if (counter
== partial_group
)
772 counter_sched_out(counter
, cpuctx
, ctx
);
774 counter_sched_out(group_counter
, cpuctx
, ctx
);
780 __perf_counter_sched_in(struct perf_counter_context
*ctx
,
781 struct perf_cpu_context
*cpuctx
, int cpu
)
783 struct perf_counter
*counter
;
787 spin_lock(&ctx
->lock
);
789 if (likely(!ctx
->nr_counters
))
792 flags
= hw_perf_save_disable();
795 * First go through the list and put on any pinned groups
796 * in order to give them the best chance of going on.
798 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
799 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
800 !counter
->hw_event
.pinned
)
802 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
805 if (group_can_go_on(counter
, cpuctx
, 1))
806 group_sched_in(counter
, cpuctx
, ctx
, cpu
);
809 * If this pinned group hasn't been scheduled,
810 * put it in error state.
812 if (counter
->state
== PERF_COUNTER_STATE_INACTIVE
)
813 counter
->state
= PERF_COUNTER_STATE_ERROR
;
816 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
818 * Ignore counters in OFF or ERROR state, and
819 * ignore pinned counters since we did them already.
821 if (counter
->state
<= PERF_COUNTER_STATE_OFF
||
822 counter
->hw_event
.pinned
)
826 * Listen to the 'cpu' scheduling filter constraint
829 if (counter
->cpu
!= -1 && counter
->cpu
!= cpu
)
832 if (group_can_go_on(counter
, cpuctx
, can_add_hw
)) {
833 if (group_sched_in(counter
, cpuctx
, ctx
, cpu
))
837 hw_perf_restore(flags
);
839 spin_unlock(&ctx
->lock
);
843 * Called from scheduler to add the counters of the current task
844 * with interrupts disabled.
846 * We restore the counter value and then enable it.
848 * This does not protect us against NMI, but enable()
849 * sets the enabled bit in the control field of counter _before_
850 * accessing the counter control register. If a NMI hits, then it will
851 * keep the counter running.
853 void perf_counter_task_sched_in(struct task_struct
*task
, int cpu
)
855 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
856 struct perf_counter_context
*ctx
= &task
->perf_counter_ctx
;
858 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
859 cpuctx
->task_ctx
= ctx
;
862 static void perf_counter_cpu_sched_in(struct perf_cpu_context
*cpuctx
, int cpu
)
864 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
866 __perf_counter_sched_in(ctx
, cpuctx
, cpu
);
869 int perf_counter_task_disable(void)
871 struct task_struct
*curr
= current
;
872 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
873 struct perf_counter
*counter
;
878 if (likely(!ctx
->nr_counters
))
881 curr_rq_lock_irq_save(&flags
);
882 cpu
= smp_processor_id();
884 /* force the update of the task clock: */
885 __task_delta_exec(curr
, 1);
887 perf_counter_task_sched_out(curr
, cpu
);
889 spin_lock(&ctx
->lock
);
892 * Disable all the counters:
894 perf_flags
= hw_perf_save_disable();
896 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
897 if (counter
->state
!= PERF_COUNTER_STATE_ERROR
)
898 counter
->state
= PERF_COUNTER_STATE_OFF
;
901 hw_perf_restore(perf_flags
);
903 spin_unlock(&ctx
->lock
);
905 curr_rq_unlock_irq_restore(&flags
);
910 int perf_counter_task_enable(void)
912 struct task_struct
*curr
= current
;
913 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
914 struct perf_counter
*counter
;
919 if (likely(!ctx
->nr_counters
))
922 curr_rq_lock_irq_save(&flags
);
923 cpu
= smp_processor_id();
925 /* force the update of the task clock: */
926 __task_delta_exec(curr
, 1);
928 perf_counter_task_sched_out(curr
, cpu
);
930 spin_lock(&ctx
->lock
);
933 * Disable all the counters:
935 perf_flags
= hw_perf_save_disable();
937 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
938 if (counter
->state
> PERF_COUNTER_STATE_OFF
)
940 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
941 counter
->hw_event
.disabled
= 0;
943 hw_perf_restore(perf_flags
);
945 spin_unlock(&ctx
->lock
);
947 perf_counter_task_sched_in(curr
, cpu
);
949 curr_rq_unlock_irq_restore(&flags
);
955 * Round-robin a context's counters:
957 static void rotate_ctx(struct perf_counter_context
*ctx
)
959 struct perf_counter
*counter
;
962 if (!ctx
->nr_counters
)
965 spin_lock(&ctx
->lock
);
967 * Rotate the first entry last (works just fine for group counters too):
969 perf_flags
= hw_perf_save_disable();
970 list_for_each_entry(counter
, &ctx
->counter_list
, list_entry
) {
971 list_move_tail(&counter
->list_entry
, &ctx
->counter_list
);
974 hw_perf_restore(perf_flags
);
976 spin_unlock(&ctx
->lock
);
979 void perf_counter_task_tick(struct task_struct
*curr
, int cpu
)
981 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
982 struct perf_counter_context
*ctx
= &curr
->perf_counter_ctx
;
983 const int rotate_percpu
= 0;
986 perf_counter_cpu_sched_out(cpuctx
);
987 perf_counter_task_sched_out(curr
, cpu
);
990 rotate_ctx(&cpuctx
->ctx
);
994 perf_counter_cpu_sched_in(cpuctx
, cpu
);
995 perf_counter_task_sched_in(curr
, cpu
);
999 * Cross CPU call to read the hardware counter
1001 static void __read(void *info
)
1003 struct perf_counter
*counter
= info
;
1004 unsigned long flags
;
1006 curr_rq_lock_irq_save(&flags
);
1007 counter
->hw_ops
->read(counter
);
1008 curr_rq_unlock_irq_restore(&flags
);
1011 static u64
perf_counter_read(struct perf_counter
*counter
)
1014 * If counter is enabled and currently active on a CPU, update the
1015 * value in the counter structure:
1017 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
) {
1018 smp_call_function_single(counter
->oncpu
,
1019 __read
, counter
, 1);
1022 return atomic64_read(&counter
->count
);
1026 * Cross CPU call to switch performance data pointers
1028 static void __perf_switch_irq_data(void *info
)
1030 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
1031 struct perf_counter
*counter
= info
;
1032 struct perf_counter_context
*ctx
= counter
->ctx
;
1033 struct perf_data
*oldirqdata
= counter
->irqdata
;
1036 * If this is a task context, we need to check whether it is
1037 * the current task context of this cpu. If not it has been
1038 * scheduled out before the smp call arrived.
1041 if (cpuctx
->task_ctx
!= ctx
)
1043 spin_lock(&ctx
->lock
);
1046 /* Change the pointer NMI safe */
1047 atomic_long_set((atomic_long_t
*)&counter
->irqdata
,
1048 (unsigned long) counter
->usrdata
);
1049 counter
->usrdata
= oldirqdata
;
1052 spin_unlock(&ctx
->lock
);
1055 static struct perf_data
*perf_switch_irq_data(struct perf_counter
*counter
)
1057 struct perf_counter_context
*ctx
= counter
->ctx
;
1058 struct perf_data
*oldirqdata
= counter
->irqdata
;
1059 struct task_struct
*task
= ctx
->task
;
1062 smp_call_function_single(counter
->cpu
,
1063 __perf_switch_irq_data
,
1065 return counter
->usrdata
;
1069 spin_lock_irq(&ctx
->lock
);
1070 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
) {
1071 counter
->irqdata
= counter
->usrdata
;
1072 counter
->usrdata
= oldirqdata
;
1073 spin_unlock_irq(&ctx
->lock
);
1076 spin_unlock_irq(&ctx
->lock
);
1077 task_oncpu_function_call(task
, __perf_switch_irq_data
, counter
);
1078 /* Might have failed, because task was scheduled out */
1079 if (counter
->irqdata
== oldirqdata
)
1082 return counter
->usrdata
;
1085 static void put_context(struct perf_counter_context
*ctx
)
1088 put_task_struct(ctx
->task
);
1091 static struct perf_counter_context
*find_get_context(pid_t pid
, int cpu
)
1093 struct perf_cpu_context
*cpuctx
;
1094 struct perf_counter_context
*ctx
;
1095 struct task_struct
*task
;
1098 * If cpu is not a wildcard then this is a percpu counter:
1101 /* Must be root to operate on a CPU counter: */
1102 if (!capable(CAP_SYS_ADMIN
))
1103 return ERR_PTR(-EACCES
);
1105 if (cpu
< 0 || cpu
> num_possible_cpus())
1106 return ERR_PTR(-EINVAL
);
1109 * We could be clever and allow to attach a counter to an
1110 * offline CPU and activate it when the CPU comes up, but
1113 if (!cpu_isset(cpu
, cpu_online_map
))
1114 return ERR_PTR(-ENODEV
);
1116 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
1126 task
= find_task_by_vpid(pid
);
1128 get_task_struct(task
);
1132 return ERR_PTR(-ESRCH
);
1134 ctx
= &task
->perf_counter_ctx
;
1137 /* Reuse ptrace permission checks for now. */
1138 if (!ptrace_may_access(task
, PTRACE_MODE_READ
)) {
1140 return ERR_PTR(-EACCES
);
1146 static void free_counter_rcu(struct rcu_head
*head
)
1148 struct perf_counter
*counter
;
1150 counter
= container_of(head
, struct perf_counter
, rcu_head
);
1154 static void free_counter(struct perf_counter
*counter
)
1156 if (counter
->destroy
)
1157 counter
->destroy(counter
);
1159 call_rcu(&counter
->rcu_head
, free_counter_rcu
);
1163 * Called when the last reference to the file is gone.
1165 static int perf_release(struct inode
*inode
, struct file
*file
)
1167 struct perf_counter
*counter
= file
->private_data
;
1168 struct perf_counter_context
*ctx
= counter
->ctx
;
1170 file
->private_data
= NULL
;
1172 mutex_lock(&ctx
->mutex
);
1173 mutex_lock(&counter
->mutex
);
1175 perf_counter_remove_from_context(counter
);
1177 mutex_unlock(&counter
->mutex
);
1178 mutex_unlock(&ctx
->mutex
);
1180 free_page(counter
->user_page
);
1181 free_counter(counter
);
1188 * Read the performance counter - simple non blocking version for now
1191 perf_read_hw(struct perf_counter
*counter
, char __user
*buf
, size_t count
)
1195 if (count
!= sizeof(cntval
))
1199 * Return end-of-file for a read on a counter that is in
1200 * error state (i.e. because it was pinned but it couldn't be
1201 * scheduled on to the CPU at some point).
1203 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1206 mutex_lock(&counter
->mutex
);
1207 cntval
= perf_counter_read(counter
);
1208 mutex_unlock(&counter
->mutex
);
1210 return put_user(cntval
, (u64 __user
*) buf
) ? -EFAULT
: sizeof(cntval
);
1214 perf_copy_usrdata(struct perf_data
*usrdata
, char __user
*buf
, size_t count
)
1219 count
= min(count
, (size_t)usrdata
->len
);
1220 if (copy_to_user(buf
, usrdata
->data
+ usrdata
->rd_idx
, count
))
1223 /* Adjust the counters */
1224 usrdata
->len
-= count
;
1226 usrdata
->rd_idx
= 0;
1228 usrdata
->rd_idx
+= count
;
1234 perf_read_irq_data(struct perf_counter
*counter
,
1239 struct perf_data
*irqdata
, *usrdata
;
1240 DECLARE_WAITQUEUE(wait
, current
);
1243 irqdata
= counter
->irqdata
;
1244 usrdata
= counter
->usrdata
;
1246 if (usrdata
->len
+ irqdata
->len
>= count
)
1252 spin_lock_irq(&counter
->waitq
.lock
);
1253 __add_wait_queue(&counter
->waitq
, &wait
);
1255 set_current_state(TASK_INTERRUPTIBLE
);
1256 if (usrdata
->len
+ irqdata
->len
>= count
)
1259 if (signal_pending(current
))
1262 if (counter
->state
== PERF_COUNTER_STATE_ERROR
)
1265 spin_unlock_irq(&counter
->waitq
.lock
);
1267 spin_lock_irq(&counter
->waitq
.lock
);
1269 __remove_wait_queue(&counter
->waitq
, &wait
);
1270 __set_current_state(TASK_RUNNING
);
1271 spin_unlock_irq(&counter
->waitq
.lock
);
1273 if (usrdata
->len
+ irqdata
->len
< count
&&
1274 counter
->state
!= PERF_COUNTER_STATE_ERROR
)
1275 return -ERESTARTSYS
;
1277 mutex_lock(&counter
->mutex
);
1279 /* Drain pending data first: */
1280 res
= perf_copy_usrdata(usrdata
, buf
, count
);
1281 if (res
< 0 || res
== count
)
1284 /* Switch irq buffer: */
1285 usrdata
= perf_switch_irq_data(counter
);
1286 res2
= perf_copy_usrdata(usrdata
, buf
+ res
, count
- res
);
1294 mutex_unlock(&counter
->mutex
);
1300 perf_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
1302 struct perf_counter
*counter
= file
->private_data
;
1304 switch (counter
->hw_event
.record_type
) {
1305 case PERF_RECORD_SIMPLE
:
1306 return perf_read_hw(counter
, buf
, count
);
1308 case PERF_RECORD_IRQ
:
1309 case PERF_RECORD_GROUP
:
1310 return perf_read_irq_data(counter
, buf
, count
,
1311 file
->f_flags
& O_NONBLOCK
);
1316 static unsigned int perf_poll(struct file
*file
, poll_table
*wait
)
1318 struct perf_counter
*counter
= file
->private_data
;
1319 unsigned int events
= 0;
1320 unsigned long flags
;
1322 poll_wait(file
, &counter
->waitq
, wait
);
1324 spin_lock_irqsave(&counter
->waitq
.lock
, flags
);
1325 if (counter
->usrdata
->len
|| counter
->irqdata
->len
)
1327 spin_unlock_irqrestore(&counter
->waitq
.lock
, flags
);
1332 static long perf_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
1334 struct perf_counter
*counter
= file
->private_data
;
1338 case PERF_COUNTER_IOC_ENABLE
:
1339 perf_counter_enable_family(counter
);
1341 case PERF_COUNTER_IOC_DISABLE
:
1342 perf_counter_disable_family(counter
);
1350 void perf_counter_update_userpage(struct perf_counter
*counter
)
1352 struct perf_counter_mmap_page
*userpg
;
1354 if (!counter
->user_page
)
1356 userpg
= (struct perf_counter_mmap_page
*) counter
->user_page
;
1360 userpg
->index
= counter
->hw
.idx
;
1361 userpg
->offset
= atomic64_read(&counter
->count
);
1362 if (counter
->state
== PERF_COUNTER_STATE_ACTIVE
)
1363 userpg
->offset
-= atomic64_read(&counter
->hw
.prev_count
);
1368 static int perf_mmap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1370 struct perf_counter
*counter
= vma
->vm_file
->private_data
;
1372 if (!counter
->user_page
)
1373 return VM_FAULT_SIGBUS
;
1375 vmf
->page
= virt_to_page(counter
->user_page
);
1376 get_page(vmf
->page
);
1380 static struct vm_operations_struct perf_mmap_vmops
= {
1381 .fault
= perf_mmap_fault
,
1384 static int perf_mmap(struct file
*file
, struct vm_area_struct
*vma
)
1386 struct perf_counter
*counter
= file
->private_data
;
1387 unsigned long userpg
;
1389 if (!(vma
->vm_flags
& VM_SHARED
) || (vma
->vm_flags
& VM_WRITE
))
1391 if (vma
->vm_end
- vma
->vm_start
!= PAGE_SIZE
)
1395 * For now, restrict to the case of a hardware counter
1396 * on the current task.
1398 if (is_software_counter(counter
) || counter
->task
!= current
)
1401 userpg
= counter
->user_page
;
1403 userpg
= get_zeroed_page(GFP_KERNEL
);
1404 mutex_lock(&counter
->mutex
);
1405 if (counter
->user_page
) {
1407 userpg
= counter
->user_page
;
1409 counter
->user_page
= userpg
;
1411 mutex_unlock(&counter
->mutex
);
1416 perf_counter_update_userpage(counter
);
1418 vma
->vm_flags
&= ~VM_MAYWRITE
;
1419 vma
->vm_flags
|= VM_RESERVED
;
1420 vma
->vm_ops
= &perf_mmap_vmops
;
1424 static const struct file_operations perf_fops
= {
1425 .release
= perf_release
,
1428 .unlocked_ioctl
= perf_ioctl
,
1429 .compat_ioctl
= perf_ioctl
,
1437 static void perf_counter_store_irq(struct perf_counter
*counter
, u64 data
)
1439 struct perf_data
*irqdata
= counter
->irqdata
;
1441 if (irqdata
->len
> PERF_DATA_BUFLEN
- sizeof(u64
)) {
1444 u64
*p
= (u64
*) &irqdata
->data
[irqdata
->len
];
1447 irqdata
->len
+= sizeof(u64
);
1451 static void perf_counter_handle_group(struct perf_counter
*counter
)
1453 struct perf_counter
*leader
, *sub
;
1455 leader
= counter
->group_leader
;
1456 list_for_each_entry(sub
, &leader
->sibling_list
, list_entry
) {
1458 sub
->hw_ops
->read(sub
);
1459 perf_counter_store_irq(counter
, sub
->hw_event
.config
);
1460 perf_counter_store_irq(counter
, atomic64_read(&sub
->count
));
1464 void perf_counter_output(struct perf_counter
*counter
,
1465 int nmi
, struct pt_regs
*regs
)
1467 switch (counter
->hw_event
.record_type
) {
1468 case PERF_RECORD_SIMPLE
:
1471 case PERF_RECORD_IRQ
:
1472 perf_counter_store_irq(counter
, instruction_pointer(regs
));
1475 case PERF_RECORD_GROUP
:
1476 perf_counter_handle_group(counter
);
1481 counter
->wakeup_pending
= 1;
1482 set_perf_counter_pending();
1484 wake_up(&counter
->waitq
);
1488 * Generic software counter infrastructure
1491 static void perf_swcounter_update(struct perf_counter
*counter
)
1493 struct hw_perf_counter
*hwc
= &counter
->hw
;
1498 prev
= atomic64_read(&hwc
->prev_count
);
1499 now
= atomic64_read(&hwc
->count
);
1500 if (atomic64_cmpxchg(&hwc
->prev_count
, prev
, now
) != prev
)
1505 atomic64_add(delta
, &counter
->count
);
1506 atomic64_sub(delta
, &hwc
->period_left
);
1509 static void perf_swcounter_set_period(struct perf_counter
*counter
)
1511 struct hw_perf_counter
*hwc
= &counter
->hw
;
1512 s64 left
= atomic64_read(&hwc
->period_left
);
1513 s64 period
= hwc
->irq_period
;
1515 if (unlikely(left
<= -period
)) {
1517 atomic64_set(&hwc
->period_left
, left
);
1520 if (unlikely(left
<= 0)) {
1522 atomic64_add(period
, &hwc
->period_left
);
1525 atomic64_set(&hwc
->prev_count
, -left
);
1526 atomic64_set(&hwc
->count
, -left
);
1529 static enum hrtimer_restart
perf_swcounter_hrtimer(struct hrtimer
*hrtimer
)
1531 struct perf_counter
*counter
;
1532 struct pt_regs
*regs
;
1534 counter
= container_of(hrtimer
, struct perf_counter
, hw
.hrtimer
);
1535 counter
->hw_ops
->read(counter
);
1537 regs
= get_irq_regs();
1539 * In case we exclude kernel IPs or are somehow not in interrupt
1540 * context, provide the next best thing, the user IP.
1542 if ((counter
->hw_event
.exclude_kernel
|| !regs
) &&
1543 !counter
->hw_event
.exclude_user
)
1544 regs
= task_pt_regs(current
);
1547 perf_counter_output(counter
, 0, regs
);
1549 hrtimer_forward_now(hrtimer
, ns_to_ktime(counter
->hw
.irq_period
));
1551 return HRTIMER_RESTART
;
1554 static void perf_swcounter_overflow(struct perf_counter
*counter
,
1555 int nmi
, struct pt_regs
*regs
)
1557 perf_swcounter_update(counter
);
1558 perf_swcounter_set_period(counter
);
1559 perf_counter_output(counter
, nmi
, regs
);
1562 static int perf_swcounter_match(struct perf_counter
*counter
,
1563 enum perf_event_types type
,
1564 u32 event
, struct pt_regs
*regs
)
1566 if (counter
->state
!= PERF_COUNTER_STATE_ACTIVE
)
1569 if (perf_event_raw(&counter
->hw_event
))
1572 if (perf_event_type(&counter
->hw_event
) != type
)
1575 if (perf_event_id(&counter
->hw_event
) != event
)
1578 if (counter
->hw_event
.exclude_user
&& user_mode(regs
))
1581 if (counter
->hw_event
.exclude_kernel
&& !user_mode(regs
))
1587 static void perf_swcounter_add(struct perf_counter
*counter
, u64 nr
,
1588 int nmi
, struct pt_regs
*regs
)
1590 int neg
= atomic64_add_negative(nr
, &counter
->hw
.count
);
1591 if (counter
->hw
.irq_period
&& !neg
)
1592 perf_swcounter_overflow(counter
, nmi
, regs
);
1595 static void perf_swcounter_ctx_event(struct perf_counter_context
*ctx
,
1596 enum perf_event_types type
, u32 event
,
1597 u64 nr
, int nmi
, struct pt_regs
*regs
)
1599 struct perf_counter
*counter
;
1601 if (system_state
!= SYSTEM_RUNNING
|| list_empty(&ctx
->event_list
))
1605 list_for_each_entry_rcu(counter
, &ctx
->event_list
, event_entry
) {
1606 if (perf_swcounter_match(counter
, type
, event
, regs
))
1607 perf_swcounter_add(counter
, nr
, nmi
, regs
);
1612 static int *perf_swcounter_recursion_context(struct perf_cpu_context
*cpuctx
)
1615 return &cpuctx
->recursion
[3];
1618 return &cpuctx
->recursion
[2];
1621 return &cpuctx
->recursion
[1];
1623 return &cpuctx
->recursion
[0];
1626 static void __perf_swcounter_event(enum perf_event_types type
, u32 event
,
1627 u64 nr
, int nmi
, struct pt_regs
*regs
)
1629 struct perf_cpu_context
*cpuctx
= &get_cpu_var(perf_cpu_context
);
1630 int *recursion
= perf_swcounter_recursion_context(cpuctx
);
1638 perf_swcounter_ctx_event(&cpuctx
->ctx
, type
, event
, nr
, nmi
, regs
);
1639 if (cpuctx
->task_ctx
) {
1640 perf_swcounter_ctx_event(cpuctx
->task_ctx
, type
, event
,
1648 put_cpu_var(perf_cpu_context
);
1651 void perf_swcounter_event(u32 event
, u64 nr
, int nmi
, struct pt_regs
*regs
)
1653 __perf_swcounter_event(PERF_TYPE_SOFTWARE
, event
, nr
, nmi
, regs
);
1656 static void perf_swcounter_read(struct perf_counter
*counter
)
1658 perf_swcounter_update(counter
);
1661 static int perf_swcounter_enable(struct perf_counter
*counter
)
1663 perf_swcounter_set_period(counter
);
1667 static void perf_swcounter_disable(struct perf_counter
*counter
)
1669 perf_swcounter_update(counter
);
1672 static const struct hw_perf_counter_ops perf_ops_generic
= {
1673 .enable
= perf_swcounter_enable
,
1674 .disable
= perf_swcounter_disable
,
1675 .read
= perf_swcounter_read
,
1679 * Software counter: cpu wall time clock
1682 static void cpu_clock_perf_counter_update(struct perf_counter
*counter
)
1684 int cpu
= raw_smp_processor_id();
1688 now
= cpu_clock(cpu
);
1689 prev
= atomic64_read(&counter
->hw
.prev_count
);
1690 atomic64_set(&counter
->hw
.prev_count
, now
);
1691 atomic64_add(now
- prev
, &counter
->count
);
1694 static int cpu_clock_perf_counter_enable(struct perf_counter
*counter
)
1696 struct hw_perf_counter
*hwc
= &counter
->hw
;
1697 int cpu
= raw_smp_processor_id();
1699 atomic64_set(&hwc
->prev_count
, cpu_clock(cpu
));
1700 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1701 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
1702 if (hwc
->irq_period
) {
1703 __hrtimer_start_range_ns(&hwc
->hrtimer
,
1704 ns_to_ktime(hwc
->irq_period
), 0,
1705 HRTIMER_MODE_REL
, 0);
1711 static void cpu_clock_perf_counter_disable(struct perf_counter
*counter
)
1713 hrtimer_cancel(&counter
->hw
.hrtimer
);
1714 cpu_clock_perf_counter_update(counter
);
1717 static void cpu_clock_perf_counter_read(struct perf_counter
*counter
)
1719 cpu_clock_perf_counter_update(counter
);
1722 static const struct hw_perf_counter_ops perf_ops_cpu_clock
= {
1723 .enable
= cpu_clock_perf_counter_enable
,
1724 .disable
= cpu_clock_perf_counter_disable
,
1725 .read
= cpu_clock_perf_counter_read
,
1729 * Software counter: task time clock
1733 * Called from within the scheduler:
1735 static u64
task_clock_perf_counter_val(struct perf_counter
*counter
, int update
)
1737 struct task_struct
*curr
= counter
->task
;
1740 delta
= __task_delta_exec(curr
, update
);
1742 return curr
->se
.sum_exec_runtime
+ delta
;
1745 static void task_clock_perf_counter_update(struct perf_counter
*counter
, u64 now
)
1750 prev
= atomic64_read(&counter
->hw
.prev_count
);
1752 atomic64_set(&counter
->hw
.prev_count
, now
);
1756 atomic64_add(delta
, &counter
->count
);
1759 static int task_clock_perf_counter_enable(struct perf_counter
*counter
)
1761 struct hw_perf_counter
*hwc
= &counter
->hw
;
1763 atomic64_set(&hwc
->prev_count
, task_clock_perf_counter_val(counter
, 0));
1764 hrtimer_init(&hwc
->hrtimer
, CLOCK_MONOTONIC
, HRTIMER_MODE_REL
);
1765 hwc
->hrtimer
.function
= perf_swcounter_hrtimer
;
1766 if (hwc
->irq_period
) {
1767 __hrtimer_start_range_ns(&hwc
->hrtimer
,
1768 ns_to_ktime(hwc
->irq_period
), 0,
1769 HRTIMER_MODE_REL
, 0);
1775 static void task_clock_perf_counter_disable(struct perf_counter
*counter
)
1777 hrtimer_cancel(&counter
->hw
.hrtimer
);
1778 task_clock_perf_counter_update(counter
,
1779 task_clock_perf_counter_val(counter
, 0));
1782 static void task_clock_perf_counter_read(struct perf_counter
*counter
)
1784 task_clock_perf_counter_update(counter
,
1785 task_clock_perf_counter_val(counter
, 1));
1788 static const struct hw_perf_counter_ops perf_ops_task_clock
= {
1789 .enable
= task_clock_perf_counter_enable
,
1790 .disable
= task_clock_perf_counter_disable
,
1791 .read
= task_clock_perf_counter_read
,
1795 * Software counter: cpu migrations
1798 static inline u64
get_cpu_migrations(struct perf_counter
*counter
)
1800 struct task_struct
*curr
= counter
->ctx
->task
;
1803 return curr
->se
.nr_migrations
;
1804 return cpu_nr_migrations(smp_processor_id());
1807 static void cpu_migrations_perf_counter_update(struct perf_counter
*counter
)
1812 prev
= atomic64_read(&counter
->hw
.prev_count
);
1813 now
= get_cpu_migrations(counter
);
1815 atomic64_set(&counter
->hw
.prev_count
, now
);
1819 atomic64_add(delta
, &counter
->count
);
1822 static void cpu_migrations_perf_counter_read(struct perf_counter
*counter
)
1824 cpu_migrations_perf_counter_update(counter
);
1827 static int cpu_migrations_perf_counter_enable(struct perf_counter
*counter
)
1829 if (counter
->prev_state
<= PERF_COUNTER_STATE_OFF
)
1830 atomic64_set(&counter
->hw
.prev_count
,
1831 get_cpu_migrations(counter
));
1835 static void cpu_migrations_perf_counter_disable(struct perf_counter
*counter
)
1837 cpu_migrations_perf_counter_update(counter
);
1840 static const struct hw_perf_counter_ops perf_ops_cpu_migrations
= {
1841 .enable
= cpu_migrations_perf_counter_enable
,
1842 .disable
= cpu_migrations_perf_counter_disable
,
1843 .read
= cpu_migrations_perf_counter_read
,
1846 #ifdef CONFIG_EVENT_PROFILE
1847 void perf_tpcounter_event(int event_id
)
1849 struct pt_regs
*regs
= get_irq_regs();
1852 regs
= task_pt_regs(current
);
1854 __perf_swcounter_event(PERF_TYPE_TRACEPOINT
, event_id
, 1, 1, regs
);
1857 extern int ftrace_profile_enable(int);
1858 extern void ftrace_profile_disable(int);
1860 static void tp_perf_counter_destroy(struct perf_counter
*counter
)
1862 ftrace_profile_disable(perf_event_id(&counter
->hw_event
));
1865 static const struct hw_perf_counter_ops
*
1866 tp_perf_counter_init(struct perf_counter
*counter
)
1868 int event_id
= perf_event_id(&counter
->hw_event
);
1871 ret
= ftrace_profile_enable(event_id
);
1875 counter
->destroy
= tp_perf_counter_destroy
;
1876 counter
->hw
.irq_period
= counter
->hw_event
.irq_period
;
1878 return &perf_ops_generic
;
1881 static const struct hw_perf_counter_ops
*
1882 tp_perf_counter_init(struct perf_counter
*counter
)
1888 static const struct hw_perf_counter_ops
*
1889 sw_perf_counter_init(struct perf_counter
*counter
)
1891 struct perf_counter_hw_event
*hw_event
= &counter
->hw_event
;
1892 const struct hw_perf_counter_ops
*hw_ops
= NULL
;
1893 struct hw_perf_counter
*hwc
= &counter
->hw
;
1896 * Software counters (currently) can't in general distinguish
1897 * between user, kernel and hypervisor events.
1898 * However, context switches and cpu migrations are considered
1899 * to be kernel events, and page faults are never hypervisor
1902 switch (perf_event_id(&counter
->hw_event
)) {
1903 case PERF_COUNT_CPU_CLOCK
:
1904 hw_ops
= &perf_ops_cpu_clock
;
1906 if (hw_event
->irq_period
&& hw_event
->irq_period
< 10000)
1907 hw_event
->irq_period
= 10000;
1909 case PERF_COUNT_TASK_CLOCK
:
1911 * If the user instantiates this as a per-cpu counter,
1912 * use the cpu_clock counter instead.
1914 if (counter
->ctx
->task
)
1915 hw_ops
= &perf_ops_task_clock
;
1917 hw_ops
= &perf_ops_cpu_clock
;
1919 if (hw_event
->irq_period
&& hw_event
->irq_period
< 10000)
1920 hw_event
->irq_period
= 10000;
1922 case PERF_COUNT_PAGE_FAULTS
:
1923 case PERF_COUNT_PAGE_FAULTS_MIN
:
1924 case PERF_COUNT_PAGE_FAULTS_MAJ
:
1925 case PERF_COUNT_CONTEXT_SWITCHES
:
1926 hw_ops
= &perf_ops_generic
;
1928 case PERF_COUNT_CPU_MIGRATIONS
:
1929 if (!counter
->hw_event
.exclude_kernel
)
1930 hw_ops
= &perf_ops_cpu_migrations
;
1935 hwc
->irq_period
= hw_event
->irq_period
;
1941 * Allocate and initialize a counter structure
1943 static struct perf_counter
*
1944 perf_counter_alloc(struct perf_counter_hw_event
*hw_event
,
1946 struct perf_counter_context
*ctx
,
1947 struct perf_counter
*group_leader
,
1950 const struct hw_perf_counter_ops
*hw_ops
;
1951 struct perf_counter
*counter
;
1953 counter
= kzalloc(sizeof(*counter
), gfpflags
);
1958 * Single counters are their own group leaders, with an
1959 * empty sibling list:
1962 group_leader
= counter
;
1964 mutex_init(&counter
->mutex
);
1965 INIT_LIST_HEAD(&counter
->list_entry
);
1966 INIT_LIST_HEAD(&counter
->event_entry
);
1967 INIT_LIST_HEAD(&counter
->sibling_list
);
1968 init_waitqueue_head(&counter
->waitq
);
1970 INIT_LIST_HEAD(&counter
->child_list
);
1972 counter
->irqdata
= &counter
->data
[0];
1973 counter
->usrdata
= &counter
->data
[1];
1975 counter
->hw_event
= *hw_event
;
1976 counter
->wakeup_pending
= 0;
1977 counter
->group_leader
= group_leader
;
1978 counter
->hw_ops
= NULL
;
1981 counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
1982 if (hw_event
->disabled
)
1983 counter
->state
= PERF_COUNTER_STATE_OFF
;
1987 if (perf_event_raw(hw_event
)) {
1988 hw_ops
= hw_perf_counter_init(counter
);
1992 switch (perf_event_type(hw_event
)) {
1993 case PERF_TYPE_HARDWARE
:
1994 hw_ops
= hw_perf_counter_init(counter
);
1997 case PERF_TYPE_SOFTWARE
:
1998 hw_ops
= sw_perf_counter_init(counter
);
2001 case PERF_TYPE_TRACEPOINT
:
2002 hw_ops
= tp_perf_counter_init(counter
);
2011 counter
->hw_ops
= hw_ops
;
2017 * sys_perf_counter_open - open a performance counter, associate it to a task/cpu
2019 * @hw_event_uptr: event type attributes for monitoring/sampling
2022 * @group_fd: group leader counter fd
2024 SYSCALL_DEFINE5(perf_counter_open
,
2025 const struct perf_counter_hw_event __user
*, hw_event_uptr
,
2026 pid_t
, pid
, int, cpu
, int, group_fd
, unsigned long, flags
)
2028 struct perf_counter
*counter
, *group_leader
;
2029 struct perf_counter_hw_event hw_event
;
2030 struct perf_counter_context
*ctx
;
2031 struct file
*counter_file
= NULL
;
2032 struct file
*group_file
= NULL
;
2033 int fput_needed
= 0;
2034 int fput_needed2
= 0;
2037 /* for future expandability... */
2041 if (copy_from_user(&hw_event
, hw_event_uptr
, sizeof(hw_event
)) != 0)
2045 * Get the target context (task or percpu):
2047 ctx
= find_get_context(pid
, cpu
);
2049 return PTR_ERR(ctx
);
2052 * Look up the group leader (we will attach this counter to it):
2054 group_leader
= NULL
;
2055 if (group_fd
!= -1) {
2057 group_file
= fget_light(group_fd
, &fput_needed
);
2059 goto err_put_context
;
2060 if (group_file
->f_op
!= &perf_fops
)
2061 goto err_put_context
;
2063 group_leader
= group_file
->private_data
;
2065 * Do not allow a recursive hierarchy (this new sibling
2066 * becoming part of another group-sibling):
2068 if (group_leader
->group_leader
!= group_leader
)
2069 goto err_put_context
;
2071 * Do not allow to attach to a group in a different
2072 * task or CPU context:
2074 if (group_leader
->ctx
!= ctx
)
2075 goto err_put_context
;
2077 * Only a group leader can be exclusive or pinned
2079 if (hw_event
.exclusive
|| hw_event
.pinned
)
2080 goto err_put_context
;
2084 counter
= perf_counter_alloc(&hw_event
, cpu
, ctx
, group_leader
,
2087 goto err_put_context
;
2089 ret
= anon_inode_getfd("[perf_counter]", &perf_fops
, counter
, 0);
2091 goto err_free_put_context
;
2093 counter_file
= fget_light(ret
, &fput_needed2
);
2095 goto err_free_put_context
;
2097 counter
->filp
= counter_file
;
2098 mutex_lock(&ctx
->mutex
);
2099 perf_install_in_context(ctx
, counter
, cpu
);
2100 mutex_unlock(&ctx
->mutex
);
2102 fput_light(counter_file
, fput_needed2
);
2105 fput_light(group_file
, fput_needed
);
2109 err_free_put_context
:
2119 * Initialize the perf_counter context in a task_struct:
2122 __perf_counter_init_context(struct perf_counter_context
*ctx
,
2123 struct task_struct
*task
)
2125 memset(ctx
, 0, sizeof(*ctx
));
2126 spin_lock_init(&ctx
->lock
);
2127 mutex_init(&ctx
->mutex
);
2128 INIT_LIST_HEAD(&ctx
->counter_list
);
2129 INIT_LIST_HEAD(&ctx
->event_list
);
2134 * inherit a counter from parent task to child task:
2136 static struct perf_counter
*
2137 inherit_counter(struct perf_counter
*parent_counter
,
2138 struct task_struct
*parent
,
2139 struct perf_counter_context
*parent_ctx
,
2140 struct task_struct
*child
,
2141 struct perf_counter
*group_leader
,
2142 struct perf_counter_context
*child_ctx
)
2144 struct perf_counter
*child_counter
;
2147 * Instead of creating recursive hierarchies of counters,
2148 * we link inherited counters back to the original parent,
2149 * which has a filp for sure, which we use as the reference
2152 if (parent_counter
->parent
)
2153 parent_counter
= parent_counter
->parent
;
2155 child_counter
= perf_counter_alloc(&parent_counter
->hw_event
,
2156 parent_counter
->cpu
, child_ctx
,
2157 group_leader
, GFP_KERNEL
);
2162 * Link it up in the child's context:
2164 child_counter
->task
= child
;
2165 list_add_counter(child_counter
, child_ctx
);
2166 child_ctx
->nr_counters
++;
2168 child_counter
->parent
= parent_counter
;
2170 * inherit into child's child as well:
2172 child_counter
->hw_event
.inherit
= 1;
2175 * Get a reference to the parent filp - we will fput it
2176 * when the child counter exits. This is safe to do because
2177 * we are in the parent and we know that the filp still
2178 * exists and has a nonzero count:
2180 atomic_long_inc(&parent_counter
->filp
->f_count
);
2183 * Link this into the parent counter's child list
2185 mutex_lock(&parent_counter
->mutex
);
2186 list_add_tail(&child_counter
->child_list
, &parent_counter
->child_list
);
2189 * Make the child state follow the state of the parent counter,
2190 * not its hw_event.disabled bit. We hold the parent's mutex,
2191 * so we won't race with perf_counter_{en,dis}able_family.
2193 if (parent_counter
->state
>= PERF_COUNTER_STATE_INACTIVE
)
2194 child_counter
->state
= PERF_COUNTER_STATE_INACTIVE
;
2196 child_counter
->state
= PERF_COUNTER_STATE_OFF
;
2198 mutex_unlock(&parent_counter
->mutex
);
2200 return child_counter
;
2203 static int inherit_group(struct perf_counter
*parent_counter
,
2204 struct task_struct
*parent
,
2205 struct perf_counter_context
*parent_ctx
,
2206 struct task_struct
*child
,
2207 struct perf_counter_context
*child_ctx
)
2209 struct perf_counter
*leader
;
2210 struct perf_counter
*sub
;
2212 leader
= inherit_counter(parent_counter
, parent
, parent_ctx
,
2213 child
, NULL
, child_ctx
);
2216 list_for_each_entry(sub
, &parent_counter
->sibling_list
, list_entry
) {
2217 if (!inherit_counter(sub
, parent
, parent_ctx
,
2218 child
, leader
, child_ctx
))
2224 static void sync_child_counter(struct perf_counter
*child_counter
,
2225 struct perf_counter
*parent_counter
)
2227 u64 parent_val
, child_val
;
2229 parent_val
= atomic64_read(&parent_counter
->count
);
2230 child_val
= atomic64_read(&child_counter
->count
);
2233 * Add back the child's count to the parent's count:
2235 atomic64_add(child_val
, &parent_counter
->count
);
2238 * Remove this counter from the parent's list
2240 mutex_lock(&parent_counter
->mutex
);
2241 list_del_init(&child_counter
->child_list
);
2242 mutex_unlock(&parent_counter
->mutex
);
2245 * Release the parent counter, if this was the last
2248 fput(parent_counter
->filp
);
2252 __perf_counter_exit_task(struct task_struct
*child
,
2253 struct perf_counter
*child_counter
,
2254 struct perf_counter_context
*child_ctx
)
2256 struct perf_counter
*parent_counter
;
2257 struct perf_counter
*sub
, *tmp
;
2260 * If we do not self-reap then we have to wait for the
2261 * child task to unschedule (it will happen for sure),
2262 * so that its counter is at its final count. (This
2263 * condition triggers rarely - child tasks usually get
2264 * off their CPU before the parent has a chance to
2265 * get this far into the reaping action)
2267 if (child
!= current
) {
2268 wait_task_inactive(child
, 0);
2269 list_del_init(&child_counter
->list_entry
);
2271 struct perf_cpu_context
*cpuctx
;
2272 unsigned long flags
;
2276 * Disable and unlink this counter.
2278 * Be careful about zapping the list - IRQ/NMI context
2279 * could still be processing it:
2281 curr_rq_lock_irq_save(&flags
);
2282 perf_flags
= hw_perf_save_disable();
2284 cpuctx
= &__get_cpu_var(perf_cpu_context
);
2286 group_sched_out(child_counter
, cpuctx
, child_ctx
);
2288 list_del_init(&child_counter
->list_entry
);
2290 child_ctx
->nr_counters
--;
2292 hw_perf_restore(perf_flags
);
2293 curr_rq_unlock_irq_restore(&flags
);
2296 parent_counter
= child_counter
->parent
;
2298 * It can happen that parent exits first, and has counters
2299 * that are still around due to the child reference. These
2300 * counters need to be zapped - but otherwise linger.
2302 if (parent_counter
) {
2303 sync_child_counter(child_counter
, parent_counter
);
2304 list_for_each_entry_safe(sub
, tmp
, &child_counter
->sibling_list
,
2307 sync_child_counter(sub
, sub
->parent
);
2311 free_counter(child_counter
);
2316 * When a child task exits, feed back counter values to parent counters.
2318 * Note: we may be running in child context, but the PID is not hashed
2319 * anymore so new counters will not be added.
2321 void perf_counter_exit_task(struct task_struct
*child
)
2323 struct perf_counter
*child_counter
, *tmp
;
2324 struct perf_counter_context
*child_ctx
;
2326 child_ctx
= &child
->perf_counter_ctx
;
2328 if (likely(!child_ctx
->nr_counters
))
2331 list_for_each_entry_safe(child_counter
, tmp
, &child_ctx
->counter_list
,
2333 __perf_counter_exit_task(child
, child_counter
, child_ctx
);
2337 * Initialize the perf_counter context in task_struct
2339 void perf_counter_init_task(struct task_struct
*child
)
2341 struct perf_counter_context
*child_ctx
, *parent_ctx
;
2342 struct perf_counter
*counter
;
2343 struct task_struct
*parent
= current
;
2345 child_ctx
= &child
->perf_counter_ctx
;
2346 parent_ctx
= &parent
->perf_counter_ctx
;
2348 __perf_counter_init_context(child_ctx
, child
);
2351 * This is executed from the parent task context, so inherit
2352 * counters that have been marked for cloning:
2355 if (likely(!parent_ctx
->nr_counters
))
2359 * Lock the parent list. No need to lock the child - not PID
2360 * hashed yet and not running, so nobody can access it.
2362 mutex_lock(&parent_ctx
->mutex
);
2365 * We dont have to disable NMIs - we are only looking at
2366 * the list, not manipulating it:
2368 list_for_each_entry(counter
, &parent_ctx
->counter_list
, list_entry
) {
2369 if (!counter
->hw_event
.inherit
)
2372 if (inherit_group(counter
, parent
,
2373 parent_ctx
, child
, child_ctx
))
2377 mutex_unlock(&parent_ctx
->mutex
);
2380 static void __cpuinit
perf_counter_init_cpu(int cpu
)
2382 struct perf_cpu_context
*cpuctx
;
2384 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
2385 __perf_counter_init_context(&cpuctx
->ctx
, NULL
);
2387 mutex_lock(&perf_resource_mutex
);
2388 cpuctx
->max_pertask
= perf_max_counters
- perf_reserved_percpu
;
2389 mutex_unlock(&perf_resource_mutex
);
2391 hw_perf_counter_setup(cpu
);
2394 #ifdef CONFIG_HOTPLUG_CPU
2395 static void __perf_counter_exit_cpu(void *info
)
2397 struct perf_cpu_context
*cpuctx
= &__get_cpu_var(perf_cpu_context
);
2398 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
2399 struct perf_counter
*counter
, *tmp
;
2401 list_for_each_entry_safe(counter
, tmp
, &ctx
->counter_list
, list_entry
)
2402 __perf_counter_remove_from_context(counter
);
2404 static void perf_counter_exit_cpu(int cpu
)
2406 struct perf_cpu_context
*cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
2407 struct perf_counter_context
*ctx
= &cpuctx
->ctx
;
2409 mutex_lock(&ctx
->mutex
);
2410 smp_call_function_single(cpu
, __perf_counter_exit_cpu
, NULL
, 1);
2411 mutex_unlock(&ctx
->mutex
);
2414 static inline void perf_counter_exit_cpu(int cpu
) { }
2417 static int __cpuinit
2418 perf_cpu_notify(struct notifier_block
*self
, unsigned long action
, void *hcpu
)
2420 unsigned int cpu
= (long)hcpu
;
2424 case CPU_UP_PREPARE
:
2425 case CPU_UP_PREPARE_FROZEN
:
2426 perf_counter_init_cpu(cpu
);
2429 case CPU_DOWN_PREPARE
:
2430 case CPU_DOWN_PREPARE_FROZEN
:
2431 perf_counter_exit_cpu(cpu
);
2441 static struct notifier_block __cpuinitdata perf_cpu_nb
= {
2442 .notifier_call
= perf_cpu_notify
,
2445 static int __init
perf_counter_init(void)
2447 perf_cpu_notify(&perf_cpu_nb
, (unsigned long)CPU_UP_PREPARE
,
2448 (void *)(long)smp_processor_id());
2449 register_cpu_notifier(&perf_cpu_nb
);
2453 early_initcall(perf_counter_init
);
2455 static ssize_t
perf_show_reserve_percpu(struct sysdev_class
*class, char *buf
)
2457 return sprintf(buf
, "%d\n", perf_reserved_percpu
);
2461 perf_set_reserve_percpu(struct sysdev_class
*class,
2465 struct perf_cpu_context
*cpuctx
;
2469 err
= strict_strtoul(buf
, 10, &val
);
2472 if (val
> perf_max_counters
)
2475 mutex_lock(&perf_resource_mutex
);
2476 perf_reserved_percpu
= val
;
2477 for_each_online_cpu(cpu
) {
2478 cpuctx
= &per_cpu(perf_cpu_context
, cpu
);
2479 spin_lock_irq(&cpuctx
->ctx
.lock
);
2480 mpt
= min(perf_max_counters
- cpuctx
->ctx
.nr_counters
,
2481 perf_max_counters
- perf_reserved_percpu
);
2482 cpuctx
->max_pertask
= mpt
;
2483 spin_unlock_irq(&cpuctx
->ctx
.lock
);
2485 mutex_unlock(&perf_resource_mutex
);
2490 static ssize_t
perf_show_overcommit(struct sysdev_class
*class, char *buf
)
2492 return sprintf(buf
, "%d\n", perf_overcommit
);
2496 perf_set_overcommit(struct sysdev_class
*class, const char *buf
, size_t count
)
2501 err
= strict_strtoul(buf
, 10, &val
);
2507 mutex_lock(&perf_resource_mutex
);
2508 perf_overcommit
= val
;
2509 mutex_unlock(&perf_resource_mutex
);
2514 static SYSDEV_CLASS_ATTR(
2517 perf_show_reserve_percpu
,
2518 perf_set_reserve_percpu
2521 static SYSDEV_CLASS_ATTR(
2524 perf_show_overcommit
,
2528 static struct attribute
*perfclass_attrs
[] = {
2529 &attr_reserve_percpu
.attr
,
2530 &attr_overcommit
.attr
,
2534 static struct attribute_group perfclass_attr_group
= {
2535 .attrs
= perfclass_attrs
,
2536 .name
= "perf_counters",
2539 static int __init
perf_counter_sysfs_init(void)
2541 return sysfs_create_group(&cpu_sysdev_class
.kset
.kobj
,
2542 &perfclass_attr_group
);
2544 device_initcall(perf_counter_sysfs_init
);