include/linux/perf_counter.h

   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
  16 #include <linux/types.h>
  17 #include <linux/ioctl.h>
  18 #include <asm/byteorder.h>
  19
  20 /*
  21  * User-space ABI bits:
  22  */
  23
  24 /*
  25  * hw_event.type
  26  */
  27 enum perf_event_types {
  28         PERF_TYPE_HARDWARE              = 0,
  29         PERF_TYPE_SOFTWARE              = 1,
  30         PERF_TYPE_TRACEPOINT            = 2,
  31
  32         /*
  33          * available TYPE space, raw is the max value.
  34          */
  35
  36         PERF_TYPE_RAW                   = 128,
  37 };
  38
  39 /*
  40  * Generalized performance counter event types, used by the hw_event.event_id
  41  * parameter of the sys_perf_counter_open() syscall:
  42  */
  43 enum hw_event_ids {
  44         /*
  45          * Common hardware events, generalized by the kernel:
  46          */
  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 };
  57
  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  */
  64 enum 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,
  74 };
  75
  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
  96 /*
  97  * Bits that can be set in hw_event.record_type to request information
  98  * in the overflow packets.
  99  */
 100 enum perf_counter_record_format {
 101         PERF_RECORD_IP                  = 1U << 0,
 102         PERF_RECORD_TID                 = 1U << 1,
 103         PERF_RECORD_TIME                = 1U << 2,
 104         PERF_RECORD_ADDR                = 1U << 3,
 105         PERF_RECORD_GROUP               = 1U << 4,
 106         PERF_RECORD_CALLCHAIN           = 1U << 5,
 107         PERF_RECORD_CONFIG              = 1U << 6,
 108         PERF_RECORD_CPU                 = 1U << 7,
 109 };
 110
 111 /*
 112  * Bits that can be set in hw_event.read_format to request that
 113  * reads on the counter should return the indicated quantities,
 114  * in increasing order of bit value, after the counter value.
 115  */
 116 enum perf_counter_read_format {
 117         PERF_FORMAT_TOTAL_TIME_ENABLED  =  1,
 118         PERF_FORMAT_TOTAL_TIME_RUNNING  =  2,
 119 };
 120
 121 /*
 122  * Hardware event to monitor via a performance monitoring counter:
 123  */
 124 struct perf_counter_hw_event {
 125         /*
 126          * The MSB of the config word signifies if the rest contains cpu
 127          * specific (raw) counter configuration data, if unset, the next
 128          * 7 bits are an event type and the rest of the bits are the event
 129          * identifier.
 130          */
 131         __u64                   config;
 132
 133         union {
 134                 __u64           irq_period;
 135                 __u64           irq_freq;
 136         };
 137
 138         __u32                   record_type;
 139         __u32                   read_format;
 140
 141         __u64                   disabled       :  1, /* off by default        */
 142                                 nmi            :  1, /* NMI sampling          */
 143                                 inherit        :  1, /* children inherit it   */
 144                                 pinned         :  1, /* must always be on PMU */
 145                                 exclusive      :  1, /* only group on PMU     */
 146                                 exclude_user   :  1, /* don't count user      */
 147                                 exclude_kernel :  1, /* ditto kernel          */
 148                                 exclude_hv     :  1, /* ditto hypervisor      */
 149                                 exclude_idle   :  1, /* don't count when idle */
 150                                 mmap           :  1, /* include mmap data     */
 151                                 munmap         :  1, /* include munmap data   */
 152                                 comm           :  1, /* include comm data     */
 153                                 freq           :  1, /* use freq, not period  */
 154
 155                                 __reserved_1   : 51;
 156
 157         __u32                   wakeup_events;  /* wakeup every n events */
 158         __u32                   __reserved_2;
 159
 160         __u64                   __reserved_3;
 161         __u64                   __reserved_4;
 162 };
 163
 164 /*
 165  * Ioctls that can be done on a perf counter fd:
 166  */
 167 #define PERF_COUNTER_IOC_ENABLE         _IOW('$', 0, u32)
 168 #define PERF_COUNTER_IOC_DISABLE        _IOW('$', 1, u32)
 169 #define PERF_COUNTER_IOC_REFRESH        _IOW('$', 2, u32)
 170 #define PERF_COUNTER_IOC_RESET          _IOW('$', 3, u32)
 171
 172 enum perf_counter_ioc_flags {
 173         PERF_IOC_FLAG_GROUP             = 1U << 0,
 174 };
 175
 176 /*
 177  * Structure of the page that can be mapped via mmap
 178  */
 179 struct perf_counter_mmap_page {
 180         __u32   version;                /* version number of this structure */
 181         __u32   compat_version;         /* lowest version this is compat with */
 182
 183         /*
 184          * Bits needed to read the hw counters in user-space.
 185          *
 186          *   u32 seq;
 187          *   s64 count;
 188          *
 189          *   do {
 190          *     seq = pc->lock;
 191          *
 192          *     barrier()
 193          *     if (pc->index) {
 194          *       count = pmc_read(pc->index - 1);
 195          *       count += pc->offset;
 196          *     } else
 197          *       goto regular_read;
 198          *
 199          *     barrier();
 200          *   } while (pc->lock != seq);
 201          *
 202          * NOTE: for obvious reason this only works on self-monitoring
 203          *       processes.
 204          */
 205         __u32   lock;                   /* seqlock for synchronization */
 206         __u32   index;                  /* hardware counter identifier */
 207         __s64   offset;                 /* add to hardware counter value */
 208
 209         /*
 210          * Control data for the mmap() data buffer.
 211          *
 212          * User-space reading this value should issue an rmb(), on SMP capable
 213          * platforms, after reading this value -- see perf_counter_wakeup().
 214          */
 215         __u32   data_head;              /* head in the data section */
 216 };
 217
 218 #define PERF_EVENT_MISC_CPUMODE_MASK    (3 << 0)
 219 #define PERF_EVENT_MISC_CPUMODE_UNKNOWN (0 << 0)
 220 #define PERF_EVENT_MISC_KERNEL          (1 << 0)
 221 #define PERF_EVENT_MISC_USER            (2 << 0)
 222 #define PERF_EVENT_MISC_HYPERVISOR      (3 << 0)
 223 #define PERF_EVENT_MISC_OVERFLOW        (1 << 2)
 224
 225 struct perf_event_header {
 226         __u32   type;
 227         __u16   misc;
 228         __u16   size;
 229 };
 230
 231 enum perf_event_type {
 232
 233         /*
 234          * The MMAP events record the PROT_EXEC mappings so that we can
 235          * correlate userspace IPs to code. They have the following structure:
 236          *
 237          * struct {
 238          *      struct perf_event_header        header;
 239          *
 240          *      u32                             pid, tid;
 241          *      u64                             addr;
 242          *      u64                             len;
 243          *      u64                             pgoff;
 244          *      char                            filename[];
 245          * };
 246          */
 247         PERF_EVENT_MMAP                 = 1,
 248         PERF_EVENT_MUNMAP               = 2,
 249
 250         /*
 251          * struct {
 252          *      struct perf_event_header        header;
 253          *
 254          *      u32                             pid, tid;
 255          *      char                            comm[];
 256          * };
 257          */
 258         PERF_EVENT_COMM                 = 3,
 259
 260         /*
 261          * struct {
 262          *      struct perf_event_header        header;
 263          *      u64                             time;
 264          *      u64                             irq_period;
 265          * };
 266          */
 267         PERF_EVENT_PERIOD               = 4,
 268
 269         /*
 270          * struct {
 271          *      struct perf_event_header        header;
 272          *      u64                             time;
 273          * };
 274          */
 275         PERF_EVENT_THROTTLE             = 5,
 276         PERF_EVENT_UNTHROTTLE           = 6,
 277
 278         /*
 279          * When header.misc & PERF_EVENT_MISC_OVERFLOW the event_type field
 280          * will be PERF_RECORD_*
 281          *
 282          * struct {
 283          *      struct perf_event_header        header;
 284          *
 285          *      { u64                   ip;       } && PERF_RECORD_IP
 286          *      { u32                   pid, tid; } && PERF_RECORD_TID
 287          *      { u64                   time;     } && PERF_RECORD_TIME
 288          *      { u64                   addr;     } && PERF_RECORD_ADDR
 289          *      { u64                   config;   } && PERF_RECORD_CONFIG
 290          *      { u32                   cpu, res; } && PERF_RECORD_CPU
 291          *
 292          *      { u64                   nr;
 293          *        { u64 event, val; }   cnt[nr];  } && PERF_RECORD_GROUP
 294          *
 295          *      { u16                   nr,
 296          *                              hv,
 297          *                              kernel,
 298          *                              user;
 299          *        u64                   ips[nr];  } && PERF_RECORD_CALLCHAIN
 300          * };
 301          */
 302 };
 303
 304 #ifdef __KERNEL__
 305 /*
 306  * Kernel-internal data types and definitions:
 307  */
 308
 309 #ifdef CONFIG_PERF_COUNTERS
 310 # include <asm/perf_counter.h>
 311 #endif
 312
 313 #include <linux/list.h>
 314 #include <linux/mutex.h>
 315 #include <linux/rculist.h>
 316 #include <linux/rcupdate.h>
 317 #include <linux/spinlock.h>
 318 #include <linux/hrtimer.h>
 319 #include <linux/fs.h>
 320 #include <asm/atomic.h>
 321
 322 struct task_struct;
 323
 324 static inline u64 perf_event_raw(struct perf_counter_hw_event *hw_event)
 325 {
 326         return hw_event->config & PERF_COUNTER_RAW_MASK;
 327 }
 328
 329 static inline u64 perf_event_config(struct perf_counter_hw_event *hw_event)
 330 {
 331         return hw_event->config & PERF_COUNTER_CONFIG_MASK;
 332 }
 333
 334 static inline u64 perf_event_type(struct perf_counter_hw_event *hw_event)
 335 {
 336         return (hw_event->config & PERF_COUNTER_TYPE_MASK) >>
 337                 PERF_COUNTER_TYPE_SHIFT;
 338 }
 339
 340 static inline u64 perf_event_id(struct perf_counter_hw_event *hw_event)
 341 {
 342         return hw_event->config & PERF_COUNTER_EVENT_MASK;
 343 }
 344
 345 /**
 346  * struct hw_perf_counter - performance counter hardware details:
 347  */
 348 struct hw_perf_counter {
 349 #ifdef CONFIG_PERF_COUNTERS
 350         union {
 351                 struct { /* hardware */
 352                         u64                             config;
 353                         unsigned long                   config_base;
 354                         unsigned long                   counter_base;
 355                         int                             nmi;
 356                         int                             idx;
 357                 };
 358                 union { /* software */
 359                         atomic64_t                      count;
 360                         struct hrtimer                  hrtimer;
 361                 };
 362         };
 363         atomic64_t                      prev_count;
 364         u64                             irq_period;
 365         atomic64_t                      period_left;
 366         u64                             interrupts;
 367 #endif
 368 };
 369
 370 struct perf_counter;
 371
 372 /**
 373  * struct pmu - generic performance monitoring unit
 374  */
 375 struct pmu {
 376         int (*enable)                   (struct perf_counter *counter);
 377         void (*disable)                 (struct perf_counter *counter);
 378         void (*read)                    (struct perf_counter *counter);
 379         void (*unthrottle)              (struct perf_counter *counter);
 380 };
 381
 382 /**
 383  * enum perf_counter_active_state - the states of a counter
 384  */
 385 enum perf_counter_active_state {
 386         PERF_COUNTER_STATE_ERROR        = -2,
 387         PERF_COUNTER_STATE_OFF          = -1,
 388         PERF_COUNTER_STATE_INACTIVE     =  0,
 389         PERF_COUNTER_STATE_ACTIVE       =  1,
 390 };
 391
 392 struct file;
 393
 394 struct perf_mmap_data {
 395         struct rcu_head                 rcu_head;
 396         int                             nr_pages;       /* nr of data pages  */
 397         int                             nr_locked;      /* nr pages mlocked  */
 398
 399         atomic_t                        poll;           /* POLL_ for wakeups */
 400         atomic_t                        head;           /* write position    */
 401         atomic_t                        events;         /* event limit       */
 402
 403         atomic_t                        done_head;      /* completed head    */
 404         atomic_t                        lock;           /* concurrent writes */
 405
 406         atomic_t                        wakeup;         /* needs a wakeup    */
 407
 408         struct perf_counter_mmap_page   *user_page;
 409         void                            *data_pages[0];
 410 };
 411
 412 struct perf_pending_entry {
 413         struct perf_pending_entry *next;
 414         void (*func)(struct perf_pending_entry *);
 415 };
 416
 417 /**
 418  * struct perf_counter - performance counter kernel representation:
 419  */
 420 struct perf_counter {
 421 #ifdef CONFIG_PERF_COUNTERS
 422         struct list_head                list_entry;
 423         struct list_head                event_entry;
 424         struct list_head                sibling_list;
 425         int                             nr_siblings;
 426         struct perf_counter             *group_leader;
 427         const struct pmu                *pmu;
 428
 429         enum perf_counter_active_state  state;
 430         enum perf_counter_active_state  prev_state;
 431         atomic64_t                      count;
 432
 433         /*
 434          * These are the total time in nanoseconds that the counter
 435          * has been enabled (i.e. eligible to run, and the task has
 436          * been scheduled in, if this is a per-task counter)
 437          * and running (scheduled onto the CPU), respectively.
 438          *
 439          * They are computed from tstamp_enabled, tstamp_running and
 440          * tstamp_stopped when the counter is in INACTIVE or ACTIVE state.
 441          */
 442         u64                             total_time_enabled;
 443         u64                             total_time_running;
 444
 445         /*
 446          * These are timestamps used for computing total_time_enabled
 447          * and total_time_running when the counter is in INACTIVE or
 448          * ACTIVE state, measured in nanoseconds from an arbitrary point
 449          * in time.
 450          * tstamp_enabled: the notional time when the counter was enabled
 451          * tstamp_running: the notional time when the counter was scheduled on
 452          * tstamp_stopped: in INACTIVE state, the notional time when the
 453          *      counter was scheduled off.
 454          */
 455         u64                             tstamp_enabled;
 456         u64                             tstamp_running;
 457         u64                             tstamp_stopped;
 458
 459         struct perf_counter_hw_event    hw_event;
 460         struct hw_perf_counter          hw;
 461
 462         struct perf_counter_context     *ctx;
 463         struct file                     *filp;
 464
 465         /*
 466          * These accumulate total time (in nanoseconds) that children
 467          * counters have been enabled and running, respectively.
 468          */
 469         atomic64_t                      child_total_time_enabled;
 470         atomic64_t                      child_total_time_running;
 471
 472         /*
 473          * Protect attach/detach and child_list:
 474          */
 475         struct mutex                    child_mutex;
 476         struct list_head                child_list;
 477         struct perf_counter             *parent;
 478
 479         int                             oncpu;
 480         int                             cpu;
 481
 482         struct list_head                owner_entry;
 483         struct task_struct              *owner;
 484
 485         /* mmap bits */
 486         struct mutex                    mmap_mutex;
 487         atomic_t                        mmap_count;
 488         struct perf_mmap_data           *data;
 489
 490         /* poll related */
 491         wait_queue_head_t               waitq;
 492         struct fasync_struct            *fasync;
 493
 494         /* delayed work for NMIs and such */
 495         int                             pending_wakeup;
 496         int                             pending_kill;
 497         int                             pending_disable;
 498         struct perf_pending_entry       pending;
 499
 500         atomic_t                        event_limit;
 501
 502         void (*destroy)(struct perf_counter *);
 503         struct rcu_head                 rcu_head;
 504 #endif
 505 };
 506
 507 /**
 508  * struct perf_counter_context - counter context structure
 509  *
 510  * Used as a container for task counters and CPU counters as well:
 511  */
 512 struct perf_counter_context {
 513         /*
 514          * Protect the states of the counters in the list,
 515          * nr_active, and the list:
 516          */
 517         spinlock_t              lock;
 518         /*
 519          * Protect the list of counters.  Locking either mutex or lock
 520          * is sufficient to ensure the list doesn't change; to change
 521          * the list you need to lock both the mutex and the spinlock.
 522          */
 523         struct mutex            mutex;
 524
 525         struct list_head        counter_list;
 526         struct list_head        event_list;
 527         int                     nr_counters;
 528         int                     nr_active;
 529         int                     is_active;
 530         atomic_t                refcount;
 531         struct task_struct      *task;
 532
 533         /*
 534          * Context clock, runs when context enabled.
 535          */
 536         u64                     time;
 537         u64                     timestamp;
 538
 539         /*
 540          * These fields let us detect when two contexts have both
 541          * been cloned (inherited) from a common ancestor.
 542          */
 543         struct perf_counter_context *parent_ctx;
 544         u64                     parent_gen;
 545         u64                     generation;
 546         struct rcu_head         rcu_head;
 547 };
 548
 549 /**
 550  * struct perf_counter_cpu_context - per cpu counter context structure
 551  */
 552 struct perf_cpu_context {
 553         struct perf_counter_context     ctx;
 554         struct perf_counter_context     *task_ctx;
 555         int                             active_oncpu;
 556         int                             max_pertask;
 557         int                             exclusive;
 558
 559         /*
 560          * Recursion avoidance:
 561          *
 562          * task, softirq, irq, nmi context
 563          */
 564         int                     recursion[4];
 565 };
 566
 567 #ifdef CONFIG_PERF_COUNTERS
 568
 569 /*
 570  * Set by architecture code:
 571  */
 572 extern int perf_max_counters;
 573
 574 extern const struct pmu *hw_perf_counter_init(struct perf_counter *counter);
 575
 576 extern void perf_counter_task_sched_in(struct task_struct *task, int cpu);
 577 extern void perf_counter_task_sched_out(struct task_struct *task,
 578                                         struct task_struct *next, int cpu);
 579 extern void perf_counter_task_tick(struct task_struct *task, int cpu);
 580 extern int perf_counter_init_task(struct task_struct *child);
 581 extern void perf_counter_exit_task(struct task_struct *child);
 582 extern void perf_counter_do_pending(void);
 583 extern void perf_counter_print_debug(void);
 584 extern void __perf_disable(void);
 585 extern bool __perf_enable(void);
 586 extern void perf_disable(void);
 587 extern void perf_enable(void);
 588 extern int perf_counter_task_disable(void);
 589 extern int perf_counter_task_enable(void);
 590 extern int hw_perf_group_sched_in(struct perf_counter *group_leader,
 591                struct perf_cpu_context *cpuctx,
 592                struct perf_counter_context *ctx, int cpu);
 593 extern void perf_counter_update_userpage(struct perf_counter *counter);
 594
 595 extern int perf_counter_overflow(struct perf_counter *counter,
 596                                  int nmi, struct pt_regs *regs, u64 addr);
 597 /*
 598  * Return 1 for a software counter, 0 for a hardware counter
 599  */
 600 static inline int is_software_counter(struct perf_counter *counter)
 601 {
 602         return !perf_event_raw(&counter->hw_event) &&
 603                 perf_event_type(&counter->hw_event) != PERF_TYPE_HARDWARE;
 604 }
 605
 606 extern void perf_swcounter_event(u32, u64, int, struct pt_regs *, u64);
 607
 608 extern void perf_counter_mmap(unsigned long addr, unsigned long len,
 609                               unsigned long pgoff, struct file *file);
 610
 611 extern void perf_counter_munmap(unsigned long addr, unsigned long len,
 612                                 unsigned long pgoff, struct file *file);
 613
 614 extern void perf_counter_comm(struct task_struct *tsk);
 615
 616 #define MAX_STACK_DEPTH         255
 617
 618 struct perf_callchain_entry {
 619         u16     nr, hv, kernel, user;
 620         u64     ip[MAX_STACK_DEPTH];
 621 };
 622
 623 extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
 624
 625 extern int sysctl_perf_counter_priv;
 626 extern int sysctl_perf_counter_mlock;
 627 extern int sysctl_perf_counter_limit;
 628
 629 extern void perf_counter_init(void);
 630
 631 #ifndef perf_misc_flags
 632 #define perf_misc_flags(regs)   (user_mode(regs) ? PERF_EVENT_MISC_USER : \
 633                                  PERF_EVENT_MISC_KERNEL)
 634 #define perf_instruction_pointer(regs)  instruction_pointer(regs)
 635 #endif
 636
 637 #else
 638 static inline void
 639 perf_counter_task_sched_in(struct task_struct *task, int cpu)           { }
 640 static inline void
 641 perf_counter_task_sched_out(struct task_struct *task,
 642                             struct task_struct *next, int cpu)          { }
 643 static inline void
 644 perf_counter_task_tick(struct task_struct *task, int cpu)               { }
 645 static inline int perf_counter_init_task(struct task_struct *child)     { return 0; }
 646 static inline void perf_counter_exit_task(struct task_struct *child)    { }
 647 static inline void perf_counter_do_pending(void)                        { }
 648 static inline void perf_counter_print_debug(void)                       { }
 649 static inline void perf_disable(void)                                   { }
 650 static inline void perf_enable(void)                                    { }
 651 static inline int perf_counter_task_disable(void)       { return -EINVAL; }
 652 static inline int perf_counter_task_enable(void)        { return -EINVAL; }
 653
 654 static inline void
 655 perf_swcounter_event(u32 event, u64 nr, int nmi,
 656                      struct pt_regs *regs, u64 addr)                    { }
 657
 658 static inline void
 659 perf_counter_mmap(unsigned long addr, unsigned long len,
 660                   unsigned long pgoff, struct file *file)               { }
 661
 662 static inline void
 663 perf_counter_munmap(unsigned long addr, unsigned long len,
 664                     unsigned long pgoff, struct file *file)             { }
 665
 666 static inline void perf_counter_comm(struct task_struct *tsk)           { }
 667 static inline void perf_counter_init(void)                              { }
 668 #endif
 669
 670 #endif /* __KERNEL__ */
 671 #endif /* _LINUX_PERF_COUNTER_H */