perf_counter: add some comments
[deliverable/linux.git] / include / linux / perf_counter.h
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1/*
2 * Performance counters:
3 *
4 * Copyright(C) 2008, Thomas Gleixner <tglx@linutronix.de>
5 * Copyright(C) 2008, Red Hat, Inc., Ingo Molnar
6 *
7 * Data type definitions, declarations, prototypes.
8 *
9 * Started by: Thomas Gleixner and Ingo Molnar
10 *
11 * For licencing details see kernel-base/COPYING
12 */
13#ifndef _LINUX_PERF_COUNTER_H
14#define _LINUX_PERF_COUNTER_H
15
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16#include <linux/types.h>
17#include <linux/ioctl.h>
9aaa131a 18#include <asm/byteorder.h>
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19
20/*
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21 * User-space ABI bits:
22 */
23
24/*
b8e83514 25 * hw_event.type
0793a61d 26 */
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27enum perf_event_types {
28 PERF_TYPE_HARDWARE = 0,
29 PERF_TYPE_SOFTWARE = 1,
30 PERF_TYPE_TRACEPOINT = 2,
31
0793a61d 32 /*
b8e83514 33 * available TYPE space, raw is the max value.
0793a61d 34 */
9f66a381 35
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36 PERF_TYPE_RAW = 128,
37};
6c594c21 38
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39/*
40 * Generalized performance counter event types, used by the hw_event.event_id
41 * parameter of the sys_perf_counter_open() syscall:
42 */
43enum hw_event_ids {
9f66a381 44 /*
b8e83514 45 * Common hardware events, generalized by the kernel:
9f66a381 46 */
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47 PERF_COUNT_CPU_CYCLES = 0,
48 PERF_COUNT_INSTRUCTIONS = 1,
49 PERF_COUNT_CACHE_REFERENCES = 2,
50 PERF_COUNT_CACHE_MISSES = 3,
51 PERF_COUNT_BRANCH_INSTRUCTIONS = 4,
52 PERF_COUNT_BRANCH_MISSES = 5,
53 PERF_COUNT_BUS_CYCLES = 6,
54
55 PERF_HW_EVENTS_MAX = 7,
56};
e077df4f 57
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58/*
59 * Special "software" counters provided by the kernel, even if the hardware
60 * does not support performance counters. These counters measure various
61 * physical and sw events of the kernel (and allow the profiling of them as
62 * well):
63 */
64enum sw_event_ids {
65 PERF_COUNT_CPU_CLOCK = 0,
66 PERF_COUNT_TASK_CLOCK = 1,
67 PERF_COUNT_PAGE_FAULTS = 2,
68 PERF_COUNT_CONTEXT_SWITCHES = 3,
69 PERF_COUNT_CPU_MIGRATIONS = 4,
70 PERF_COUNT_PAGE_FAULTS_MIN = 5,
71 PERF_COUNT_PAGE_FAULTS_MAJ = 6,
72
73 PERF_SW_EVENTS_MAX = 7,
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74};
75
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76#define __PERF_COUNTER_MASK(name) \
77 (((1ULL << PERF_COUNTER_##name##_BITS) - 1) << \
78 PERF_COUNTER_##name##_SHIFT)
79
80#define PERF_COUNTER_RAW_BITS 1
81#define PERF_COUNTER_RAW_SHIFT 63
82#define PERF_COUNTER_RAW_MASK __PERF_COUNTER_MASK(RAW)
83
84#define PERF_COUNTER_CONFIG_BITS 63
85#define PERF_COUNTER_CONFIG_SHIFT 0
86#define PERF_COUNTER_CONFIG_MASK __PERF_COUNTER_MASK(CONFIG)
87
88#define PERF_COUNTER_TYPE_BITS 7
89#define PERF_COUNTER_TYPE_SHIFT 56
90#define PERF_COUNTER_TYPE_MASK __PERF_COUNTER_MASK(TYPE)
91
92#define PERF_COUNTER_EVENT_BITS 56
93#define PERF_COUNTER_EVENT_SHIFT 0
94#define PERF_COUNTER_EVENT_MASK __PERF_COUNTER_MASK(EVENT)
95
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96/*
97 * Bits that can be set in hw_event.record_type to request information
98 * in the overflow packets.
99 */
100enum perf_counter_record_format {
101 PERF_RECORD_IP = 1U << 0,
102 PERF_RECORD_TID = 1U << 1,
103 PERF_RECORD_GROUP = 1U << 2,
104 PERF_RECORD_CALLCHAIN = 1U << 3,
339f7c90 105 PERF_RECORD_TIME = 1U << 4,
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106};
107
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108/*
109 * Bits that can be set in hw_event.read_format to request that
110 * reads on the counter should return the indicated quantities,
111 * in increasing order of bit value, after the counter value.
112 */
113enum perf_counter_read_format {
114 PERF_FORMAT_TOTAL_TIME_ENABLED = 1,
115 PERF_FORMAT_TOTAL_TIME_RUNNING = 2,
116};
117
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118/*
119 * Hardware event to monitor via a performance monitoring counter:
120 */
121struct perf_counter_hw_event {
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122 /*
123 * The MSB of the config word signifies if the rest contains cpu
124 * specific (raw) counter configuration data, if unset, the next
125 * 7 bits are an event type and the rest of the bits are the event
126 * identifier.
127 */
128 __u64 config;
9f66a381 129
f3dfd265 130 __u64 irq_period;
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131 __u32 record_type;
132 __u32 read_format;
9f66a381 133
2743a5b0 134 __u64 disabled : 1, /* off by default */
0475f9ea 135 nmi : 1, /* NMI sampling */
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136 inherit : 1, /* children inherit it */
137 pinned : 1, /* must always be on PMU */
138 exclusive : 1, /* only group on PMU */
139 exclude_user : 1, /* don't count user */
140 exclude_kernel : 1, /* ditto kernel */
141 exclude_hv : 1, /* ditto hypervisor */
2743a5b0 142 exclude_idle : 1, /* don't count when idle */
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143 mmap : 1, /* include mmap data */
144 munmap : 1, /* include munmap data */
0475f9ea 145
8a057d84 146 __reserved_1 : 53;
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147
148 __u32 extra_config_len;
c457810a 149 __u32 wakeup_events; /* wakeup every n events */
9f66a381 150
f3dfd265 151 __u64 __reserved_2;
2743a5b0 152 __u64 __reserved_3;
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153};
154
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155/*
156 * Ioctls that can be done on a perf counter fd:
157 */
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158#define PERF_COUNTER_IOC_ENABLE _IO ('$', 0)
159#define PERF_COUNTER_IOC_DISABLE _IO ('$', 1)
160#define PERF_COUNTER_IOC_REFRESH _IOW('$', 2, u32)
d859e29f 161
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162/*
163 * Structure of the page that can be mapped via mmap
164 */
165struct perf_counter_mmap_page {
166 __u32 version; /* version number of this structure */
167 __u32 compat_version; /* lowest version this is compat with */
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168
169 /*
170 * Bits needed to read the hw counters in user-space.
171 *
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172 * u32 seq;
173 * s64 count;
38ff667b 174 *
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175 * do {
176 * seq = pc->lock;
38ff667b 177 *
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178 * barrier()
179 * if (pc->index) {
180 * count = pmc_read(pc->index - 1);
181 * count += pc->offset;
182 * } else
183 * goto regular_read;
38ff667b 184 *
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185 * barrier();
186 * } while (pc->lock != seq);
38ff667b 187 *
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188 * NOTE: for obvious reason this only works on self-monitoring
189 * processes.
38ff667b 190 */
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191 __u32 lock; /* seqlock for synchronization */
192 __u32 index; /* hardware counter identifier */
193 __s64 offset; /* add to hardware counter value */
7b732a75 194
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195 /*
196 * Control data for the mmap() data buffer.
197 *
198 * User-space reading this value should issue an rmb(), on SMP capable
199 * platforms, after reading this value -- see perf_counter_wakeup().
200 */
7b732a75 201 __u32 data_head; /* head in the data section */
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202};
203
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204#define PERF_EVENT_MISC_KERNEL (1 << 0)
205#define PERF_EVENT_MISC_USER (1 << 1)
206#define PERF_EVENT_MISC_OVERFLOW (1 << 2)
6fab0192 207
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208struct perf_event_header {
209 __u32 type;
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210 __u16 misc;
211 __u16 size;
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212};
213
214enum perf_event_type {
5ed00415 215
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216 /*
217 * The MMAP events record the PROT_EXEC mappings so that we can
218 * correlate userspace IPs to code. They have the following structure:
219 *
220 * struct {
221 * struct perf_event_header header;
222 *
223 * u32 pid, tid;
224 * u64 addr;
225 * u64 len;
226 * u64 pgoff;
227 * char filename[];
228 * };
229 */
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230 PERF_EVENT_MMAP = 1,
231 PERF_EVENT_MUNMAP = 2,
0a4a9391 232
8a057d84 233 /*
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234 * When header.misc & PERF_EVENT_MISC_OVERFLOW the event_type field
235 * will be PERF_RECORD_*
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236 *
237 * struct {
238 * struct perf_event_header header;
239 *
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240 * { u64 ip; } && PERF_RECORD_IP
241 * { u32 pid, tid; } && PERF_RECORD_TID
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242 *
243 * { u64 nr;
6b6e5486 244 * { u64 event, val; } cnt[nr]; } && PERF_RECORD_GROUP
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245 *
246 * { u16 nr,
247 * hv,
248 * kernel,
249 * user;
6b6e5486 250 * u64 ips[nr]; } && PERF_RECORD_CALLCHAIN
0c593b34 251 *
6b6e5486 252 * { u64 time; } && PERF_RECORD_TIME
0c593b34 253 * };
8a057d84 254 */
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255};
256
f3dfd265 257#ifdef __KERNEL__
9f66a381 258/*
f3dfd265 259 * Kernel-internal data types and definitions:
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260 */
261
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262#ifdef CONFIG_PERF_COUNTERS
263# include <asm/perf_counter.h>
264#endif
265
266#include <linux/list.h>
267#include <linux/mutex.h>
268#include <linux/rculist.h>
269#include <linux/rcupdate.h>
270#include <linux/spinlock.h>
d6d020e9 271#include <linux/hrtimer.h>
3c446b3d 272#include <linux/fs.h>
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273#include <asm/atomic.h>
274
275struct task_struct;
276
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277static inline u64 perf_event_raw(struct perf_counter_hw_event *hw_event)
278{
279 return hw_event->config & PERF_COUNTER_RAW_MASK;
280}
281
282static inline u64 perf_event_config(struct perf_counter_hw_event *hw_event)
283{
284 return hw_event->config & PERF_COUNTER_CONFIG_MASK;
285}
286
287static inline u64 perf_event_type(struct perf_counter_hw_event *hw_event)
288{
289 return (hw_event->config & PERF_COUNTER_TYPE_MASK) >>
290 PERF_COUNTER_TYPE_SHIFT;
291}
292
293static inline u64 perf_event_id(struct perf_counter_hw_event *hw_event)
294{
295 return hw_event->config & PERF_COUNTER_EVENT_MASK;
296}
297
0793a61d 298/**
9f66a381 299 * struct hw_perf_counter - performance counter hardware details:
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300 */
301struct hw_perf_counter {
ee06094f 302#ifdef CONFIG_PERF_COUNTERS
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303 union {
304 struct { /* hardware */
305 u64 config;
306 unsigned long config_base;
307 unsigned long counter_base;
308 int nmi;
309 unsigned int idx;
310 };
311 union { /* software */
312 atomic64_t count;
313 struct hrtimer hrtimer;
314 };
315 };
ee06094f 316 atomic64_t prev_count;
9f66a381 317 u64 irq_period;
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318 atomic64_t period_left;
319#endif
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320};
321
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322struct perf_counter;
323
324/**
325 * struct hw_perf_counter_ops - performance counter hw ops
326 */
327struct hw_perf_counter_ops {
95cdd2e7 328 int (*enable) (struct perf_counter *counter);
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329 void (*disable) (struct perf_counter *counter);
330 void (*read) (struct perf_counter *counter);
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331};
332
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333/**
334 * enum perf_counter_active_state - the states of a counter
335 */
336enum perf_counter_active_state {
3b6f9e5c 337 PERF_COUNTER_STATE_ERROR = -2,
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338 PERF_COUNTER_STATE_OFF = -1,
339 PERF_COUNTER_STATE_INACTIVE = 0,
340 PERF_COUNTER_STATE_ACTIVE = 1,
341};
342
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343struct file;
344
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345struct perf_mmap_data {
346 struct rcu_head rcu_head;
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347 int nr_pages; /* nr of data pages */
348
349 atomic_t wakeup; /* POLL_ for wakeups */
350 atomic_t head; /* write position */
351 atomic_t events; /* event limit */
352
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353 struct perf_counter_mmap_page *user_page;
354 void *data_pages[0];
355};
356
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357struct perf_pending_entry {
358 struct perf_pending_entry *next;
359 void (*func)(struct perf_pending_entry *);
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360};
361
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362/**
363 * struct perf_counter - performance counter kernel representation:
364 */
365struct perf_counter {
ee06094f 366#ifdef CONFIG_PERF_COUNTERS
04289bb9 367 struct list_head list_entry;
592903cd 368 struct list_head event_entry;
04289bb9 369 struct list_head sibling_list;
5c148194 370 int nr_siblings;
04289bb9 371 struct perf_counter *group_leader;
5c92d124 372 const struct hw_perf_counter_ops *hw_ops;
04289bb9 373
6a930700 374 enum perf_counter_active_state state;
c07c99b6 375 enum perf_counter_active_state prev_state;
0793a61d 376 atomic64_t count;
ee06094f 377
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378 /*
379 * These are the total time in nanoseconds that the counter
380 * has been enabled (i.e. eligible to run, and the task has
381 * been scheduled in, if this is a per-task counter)
382 * and running (scheduled onto the CPU), respectively.
383 *
384 * They are computed from tstamp_enabled, tstamp_running and
385 * tstamp_stopped when the counter is in INACTIVE or ACTIVE state.
386 */
387 u64 total_time_enabled;
388 u64 total_time_running;
389
390 /*
391 * These are timestamps used for computing total_time_enabled
392 * and total_time_running when the counter is in INACTIVE or
393 * ACTIVE state, measured in nanoseconds from an arbitrary point
394 * in time.
395 * tstamp_enabled: the notional time when the counter was enabled
396 * tstamp_running: the notional time when the counter was scheduled on
397 * tstamp_stopped: in INACTIVE state, the notional time when the
398 * counter was scheduled off.
399 */
400 u64 tstamp_enabled;
401 u64 tstamp_running;
402 u64 tstamp_stopped;
403
9f66a381 404 struct perf_counter_hw_event hw_event;
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405 struct hw_perf_counter hw;
406
407 struct perf_counter_context *ctx;
408 struct task_struct *task;
9b51f66d 409 struct file *filp;
0793a61d 410
9b51f66d 411 struct perf_counter *parent;
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412 struct list_head child_list;
413
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414 /*
415 * These accumulate total time (in nanoseconds) that children
416 * counters have been enabled and running, respectively.
417 */
418 atomic64_t child_total_time_enabled;
419 atomic64_t child_total_time_running;
420
0793a61d 421 /*
d859e29f 422 * Protect attach/detach and child_list:
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423 */
424 struct mutex mutex;
425
426 int oncpu;
427 int cpu;
428
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429 /* mmap bits */
430 struct mutex mmap_mutex;
431 atomic_t mmap_count;
432 struct perf_mmap_data *data;
37d81828 433
7b732a75 434 /* poll related */
0793a61d 435 wait_queue_head_t waitq;
3c446b3d 436 struct fasync_struct *fasync;
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437
438 /* delayed work for NMIs and such */
439 int pending_wakeup;
4c9e2542 440 int pending_kill;
79f14641 441 int pending_disable;
671dec5d 442 struct perf_pending_entry pending;
592903cd 443
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444 atomic_t event_limit;
445
e077df4f 446 void (*destroy)(struct perf_counter *);
592903cd 447 struct rcu_head rcu_head;
ee06094f 448#endif
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449};
450
451/**
452 * struct perf_counter_context - counter context structure
453 *
454 * Used as a container for task counters and CPU counters as well:
455 */
456struct perf_counter_context {
457#ifdef CONFIG_PERF_COUNTERS
458 /*
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459 * Protect the states of the counters in the list,
460 * nr_active, and the list:
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461 */
462 spinlock_t lock;
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463 /*
464 * Protect the list of counters. Locking either mutex or lock
465 * is sufficient to ensure the list doesn't change; to change
466 * the list you need to lock both the mutex and the spinlock.
467 */
468 struct mutex mutex;
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469
470 struct list_head counter_list;
592903cd 471 struct list_head event_list;
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472 int nr_counters;
473 int nr_active;
d859e29f 474 int is_active;
0793a61d 475 struct task_struct *task;
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476
477 /*
4af4998b 478 * Context clock, runs when context enabled.
53cfbf59 479 */
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480 u64 time;
481 u64 timestamp;
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482#endif
483};
484
485/**
486 * struct perf_counter_cpu_context - per cpu counter context structure
487 */
488struct perf_cpu_context {
489 struct perf_counter_context ctx;
490 struct perf_counter_context *task_ctx;
491 int active_oncpu;
492 int max_pertask;
3b6f9e5c 493 int exclusive;
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494
495 /*
496 * Recursion avoidance:
497 *
498 * task, softirq, irq, nmi context
499 */
500 int recursion[4];
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501};
502
503/*
504 * Set by architecture code:
505 */
506extern int perf_max_counters;
507
508#ifdef CONFIG_PERF_COUNTERS
5c92d124 509extern const struct hw_perf_counter_ops *
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510hw_perf_counter_init(struct perf_counter *counter);
511
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512extern void perf_counter_task_sched_in(struct task_struct *task, int cpu);
513extern void perf_counter_task_sched_out(struct task_struct *task, int cpu);
514extern void perf_counter_task_tick(struct task_struct *task, int cpu);
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515extern void perf_counter_init_task(struct task_struct *child);
516extern void perf_counter_exit_task(struct task_struct *child);
925d519a 517extern void perf_counter_do_pending(void);
0793a61d 518extern void perf_counter_print_debug(void);
1b023a96 519extern void perf_counter_unthrottle(void);
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520extern u64 hw_perf_save_disable(void);
521extern void hw_perf_restore(u64 ctrl);
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522extern int perf_counter_task_disable(void);
523extern int perf_counter_task_enable(void);
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524extern int hw_perf_group_sched_in(struct perf_counter *group_leader,
525 struct perf_cpu_context *cpuctx,
526 struct perf_counter_context *ctx, int cpu);
37d81828 527extern void perf_counter_update_userpage(struct perf_counter *counter);
5c92d124 528
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529extern int perf_counter_overflow(struct perf_counter *counter,
530 int nmi, struct pt_regs *regs);
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531/*
532 * Return 1 for a software counter, 0 for a hardware counter
533 */
534static inline int is_software_counter(struct perf_counter *counter)
535{
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536 return !perf_event_raw(&counter->hw_event) &&
537 perf_event_type(&counter->hw_event) != PERF_TYPE_HARDWARE;
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538}
539
b8e83514 540extern void perf_swcounter_event(u32, u64, int, struct pt_regs *);
15dbf27c 541
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542extern void perf_counter_mmap(unsigned long addr, unsigned long len,
543 unsigned long pgoff, struct file *file);
544
545extern void perf_counter_munmap(unsigned long addr, unsigned long len,
546 unsigned long pgoff, struct file *file);
547
9c03d88e 548#define MAX_STACK_DEPTH 255
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549
550struct perf_callchain_entry {
9c03d88e 551 u16 nr, hv, kernel, user;
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552 u64 ip[MAX_STACK_DEPTH];
553};
554
555extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
556
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557#else
558static inline void
559perf_counter_task_sched_in(struct task_struct *task, int cpu) { }
560static inline void
561perf_counter_task_sched_out(struct task_struct *task, int cpu) { }
562static inline void
563perf_counter_task_tick(struct task_struct *task, int cpu) { }
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564static inline void perf_counter_init_task(struct task_struct *child) { }
565static inline void perf_counter_exit_task(struct task_struct *child) { }
925d519a 566static inline void perf_counter_do_pending(void) { }
0793a61d 567static inline void perf_counter_print_debug(void) { }
1b023a96 568static inline void perf_counter_unthrottle(void) { }
15dbf27c 569static inline void hw_perf_restore(u64 ctrl) { }
01b2838c 570static inline u64 hw_perf_save_disable(void) { return 0; }
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571static inline int perf_counter_task_disable(void) { return -EINVAL; }
572static inline int perf_counter_task_enable(void) { return -EINVAL; }
15dbf27c 573
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574static inline void
575perf_swcounter_event(u32 event, u64 nr, int nmi, struct pt_regs *regs) { }
576
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577
578static inline void
579perf_counter_mmap(unsigned long addr, unsigned long len,
580 unsigned long pgoff, struct file *file) { }
581
582static inline void
583perf_counter_munmap(unsigned long addr, unsigned long len,
584 unsigned long pgoff, struct file *file) { }
585
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586#endif
587
f3dfd265 588#endif /* __KERNEL__ */
0793a61d 589#endif /* _LINUX_PERF_COUNTER_H */
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