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  * attr.type
  26  */
  27 enum perf_event_types {
  28         PERF_TYPE_HARDWARE              = 0,
  29         PERF_TYPE_SOFTWARE              = 1,
  30         PERF_TYPE_TRACEPOINT            = 2,
  31         PERF_TYPE_HW_CACHE              = 3,
  32
  33         /*
  34          * available TYPE space, raw is the max value.
  35          */
  36
  37         PERF_TYPE_RAW                   = 128,
  38 };
  39
  40 /*
  41  * Generalized performance counter event types, used by the attr.event_id
  42  * parameter of the sys_perf_counter_open() syscall:
  43  */
  44 enum attr_ids {
  45         /*
  46          * Common hardware events, generalized by the kernel:
  47          */
  48         PERF_COUNT_CPU_CYCLES           = 0,
  49         PERF_COUNT_INSTRUCTIONS         = 1,
  50         PERF_COUNT_CACHE_REFERENCES     = 2,
  51         PERF_COUNT_CACHE_MISSES         = 3,
  52         PERF_COUNT_BRANCH_INSTRUCTIONS  = 4,
  53         PERF_COUNT_BRANCH_MISSES        = 5,
  54         PERF_COUNT_BUS_CYCLES           = 6,
  55
  56         PERF_HW_EVENTS_MAX              = 7,
  57 };
  58
  59 /*
  60  * Generalized hardware cache counters:
  61  *
  62  *       { L1-D, L1-I, L2, LLC, ITLB, DTLB, BPU } x
  63  *       { read, write, prefetch } x
  64  *       { accesses, misses }
  65  */
  66 enum hw_cache_id {
  67         PERF_COUNT_HW_CACHE_L1D,
  68         PERF_COUNT_HW_CACHE_L1I,
  69         PERF_COUNT_HW_CACHE_L2,
  70         PERF_COUNT_HW_CACHE_DTLB,
  71         PERF_COUNT_HW_CACHE_ITLB,
  72         PERF_COUNT_HW_CACHE_BPU,
  73
  74         PERF_COUNT_HW_CACHE_MAX,
  75 };
  76
  77 enum hw_cache_op_id {
  78         PERF_COUNT_HW_CACHE_OP_READ,
  79         PERF_COUNT_HW_CACHE_OP_WRITE,
  80         PERF_COUNT_HW_CACHE_OP_PREFETCH,
  81
  82         PERF_COUNT_HW_CACHE_OP_MAX,
  83 };
  84
  85 enum hw_cache_op_result_id {
  86         PERF_COUNT_HW_CACHE_RESULT_ACCESS,
  87         PERF_COUNT_HW_CACHE_RESULT_MISS,
  88
  89         PERF_COUNT_HW_CACHE_RESULT_MAX,
  90 };
  91
  92 /*
  93  * Special "software" counters provided by the kernel, even if the hardware
  94  * does not support performance counters. These counters measure various
  95  * physical and sw events of the kernel (and allow the profiling of them as
  96  * well):
  97  */
  98 enum sw_event_ids {
  99         PERF_COUNT_CPU_CLOCK            = 0,
 100         PERF_COUNT_TASK_CLOCK           = 1,
 101         PERF_COUNT_PAGE_FAULTS          = 2,
 102         PERF_COUNT_CONTEXT_SWITCHES     = 3,
 103         PERF_COUNT_CPU_MIGRATIONS       = 4,
 104         PERF_COUNT_PAGE_FAULTS_MIN      = 5,
 105         PERF_COUNT_PAGE_FAULTS_MAJ      = 6,
 106
 107         PERF_SW_EVENTS_MAX              = 7,
 108 };
 109
 110 /*
 111  * Bits that can be set in attr.sample_type to request information
 112  * in the overflow packets.
 113  */
 114 enum perf_counter_sample_format {
 115         PERF_SAMPLE_IP                  = 1U << 0,
 116         PERF_SAMPLE_TID                 = 1U << 1,
 117         PERF_SAMPLE_TIME                = 1U << 2,
 118         PERF_SAMPLE_ADDR                = 1U << 3,
 119         PERF_SAMPLE_GROUP               = 1U << 4,
 120         PERF_SAMPLE_CALLCHAIN           = 1U << 5,
 121         PERF_SAMPLE_ID                  = 1U << 6,
 122         PERF_SAMPLE_CPU                 = 1U << 7,
 123         PERF_SAMPLE_PERIOD              = 1U << 8,
 124 };
 125
 126 /*
 127  * Bits that can be set in attr.read_format to request that
 128  * reads on the counter should return the indicated quantities,
 129  * in increasing order of bit value, after the counter value.
 130  */
 131 enum perf_counter_read_format {
 132         PERF_FORMAT_TOTAL_TIME_ENABLED  =  1U << 0,
 133         PERF_FORMAT_TOTAL_TIME_RUNNING  =  1U << 1,
 134         PERF_FORMAT_ID                  =  1U << 2,
 135 };
 136
 137 /*
 138  * Hardware event to monitor via a performance monitoring counter:
 139  */
 140 struct perf_counter_attr {
 141         /*
 142          * Major type: hardware/software/tracepoint/etc.
 143          */
 144         __u32                   type;
 145         __u32                   __reserved_1;
 146
 147         /*
 148          * Type specific configuration information.
 149          */
 150         __u64                   config;
 151
 152         union {
 153                 __u64           sample_period;
 154                 __u64           sample_freq;
 155         };
 156
 157         __u64                   sample_type;
 158         __u64                   read_format;
 159
 160         __u64                   disabled       :  1, /* off by default        */
 161                                 inherit        :  1, /* children inherit it   */
 162                                 pinned         :  1, /* must always be on PMU */
 163                                 exclusive      :  1, /* only group on PMU     */
 164                                 exclude_user   :  1, /* don't count user      */
 165                                 exclude_kernel :  1, /* ditto kernel          */
 166                                 exclude_hv     :  1, /* ditto hypervisor      */
 167                                 exclude_idle   :  1, /* don't count when idle */
 168                                 mmap           :  1, /* include mmap data     */
 169                                 comm           :  1, /* include comm data     */
 170                                 freq           :  1, /* use freq, not period  */
 171
 172                                 __reserved_2   : 53;
 173
 174         __u32                   wakeup_events;  /* wakeup every n events */
 175         __u32                   __reserved_3;
 176
 177         __u64                   __reserved_4;
 178 };
 179
 180 /*
 181  * Ioctls that can be done on a perf counter fd:
 182  */
 183 #define PERF_COUNTER_IOC_ENABLE         _IO ('$', 0)
 184 #define PERF_COUNTER_IOC_DISABLE        _IO ('$', 1)
 185 #define PERF_COUNTER_IOC_REFRESH        _IO ('$', 2)
 186 #define PERF_COUNTER_IOC_RESET          _IO ('$', 3)
 187 #define PERF_COUNTER_IOC_PERIOD         _IOW('$', 4, u64)
 188
 189 enum perf_counter_ioc_flags {
 190         PERF_IOC_FLAG_GROUP             = 1U << 0,
 191 };
 192
 193 /*
 194  * Structure of the page that can be mapped via mmap
 195  */
 196 struct perf_counter_mmap_page {
 197         __u32   version;                /* version number of this structure */
 198         __u32   compat_version;         /* lowest version this is compat with */
 199
 200         /*
 201          * Bits needed to read the hw counters in user-space.
 202          *
 203          *   u32 seq;
 204          *   s64 count;
 205          *
 206          *   do {
 207          *     seq = pc->lock;
 208          *
 209          *     barrier()
 210          *     if (pc->index) {
 211          *       count = pmc_read(pc->index - 1);
 212          *       count += pc->offset;
 213          *     } else
 214          *       goto regular_read;
 215          *
 216          *     barrier();
 217          *   } while (pc->lock != seq);
 218          *
 219          * NOTE: for obvious reason this only works on self-monitoring
 220          *       processes.
 221          */
 222         __u32   lock;                   /* seqlock for synchronization */
 223         __u32   index;                  /* hardware counter identifier */
 224         __s64   offset;                 /* add to hardware counter value */
 225
 226         /*
 227          * Control data for the mmap() data buffer.
 228          *
 229          * User-space reading this value should issue an rmb(), on SMP capable
 230          * platforms, after reading this value -- see perf_counter_wakeup().
 231          */
 232         __u64   data_head;              /* head in the data section */
 233 };
 234
 235 #define PERF_EVENT_MISC_CPUMODE_MASK    (3 << 0)
 236 #define PERF_EVENT_MISC_CPUMODE_UNKNOWN (0 << 0)
 237 #define PERF_EVENT_MISC_KERNEL          (1 << 0)
 238 #define PERF_EVENT_MISC_USER            (2 << 0)
 239 #define PERF_EVENT_MISC_HYPERVISOR      (3 << 0)
 240 #define PERF_EVENT_MISC_OVERFLOW        (1 << 2)
 241
 242 struct perf_event_header {
 243         __u32   type;
 244         __u16   misc;
 245         __u16   size;
 246 };
 247
 248 enum perf_event_type {
 249
 250         /*
 251          * The MMAP events record the PROT_EXEC mappings so that we can
 252          * correlate userspace IPs to code. They have the following structure:
 253          *
 254          * struct {
 255          *      struct perf_event_header        header;
 256          *
 257          *      u32                             pid, tid;
 258          *      u64                             addr;
 259          *      u64                             len;
 260          *      u64                             pgoff;
 261          *      char                            filename[];
 262          * };
 263          */
 264         PERF_EVENT_MMAP                 = 1,
 265
 266         /*
 267          * struct {
 268          *      struct perf_event_header        header;
 269          *
 270          *      u32                             pid, tid;
 271          *      char                            comm[];
 272          * };
 273          */
 274         PERF_EVENT_COMM                 = 3,
 275
 276         /*
 277          * struct {
 278          *      struct perf_event_header        header;
 279          *      u64                             time;
 280          *      u64                             id;
 281          *      u64                             sample_period;
 282          * };
 283          */
 284         PERF_EVENT_PERIOD               = 4,
 285
 286         /*
 287          * struct {
 288          *      struct perf_event_header        header;
 289          *      u64                             time;
 290          * };
 291          */
 292         PERF_EVENT_THROTTLE             = 5,
 293         PERF_EVENT_UNTHROTTLE           = 6,
 294
 295         /*
 296          * struct {
 297          *      struct perf_event_header        header;
 298          *      u32                             pid, ppid;
 299          * };
 300          */
 301         PERF_EVENT_FORK                 = 7,
 302
 303         /*
 304          * When header.misc & PERF_EVENT_MISC_OVERFLOW the event_type field
 305          * will be PERF_RECORD_*
 306          *
 307          * struct {
 308          *      struct perf_event_header        header;
 309          *
 310          *      { u64                   ip;       } && PERF_RECORD_IP
 311          *      { u32                   pid, tid; } && PERF_RECORD_TID
 312          *      { u64                   time;     } && PERF_RECORD_TIME
 313          *      { u64                   addr;     } && PERF_RECORD_ADDR
 314          *      { u64                   config;   } && PERF_RECORD_CONFIG
 315          *      { u32                   cpu, res; } && PERF_RECORD_CPU
 316          *
 317          *      { u64                   nr;
 318          *        { u64 id, val; }      cnt[nr];  } && PERF_RECORD_GROUP
 319          *
 320          *      { u16                   nr,
 321          *                              hv,
 322          *                              kernel,
 323          *                              user;
 324          *        u64                   ips[nr];  } && PERF_RECORD_CALLCHAIN
 325          * };
 326          */
 327 };
 328
 329 #ifdef __KERNEL__
 330 /*
 331  * Kernel-internal data types and definitions:
 332  */
 333
 334 #ifdef CONFIG_PERF_COUNTERS
 335 # include <asm/perf_counter.h>
 336 #endif
 337
 338 #include <linux/list.h>
 339 #include <linux/mutex.h>
 340 #include <linux/rculist.h>
 341 #include <linux/rcupdate.h>
 342 #include <linux/spinlock.h>
 343 #include <linux/hrtimer.h>
 344 #include <linux/fs.h>
 345 #include <linux/pid_namespace.h>
 346 #include <asm/atomic.h>
 347
 348 struct task_struct;
 349
 350 /**
 351  * struct hw_perf_counter - performance counter hardware details:
 352  */
 353 struct hw_perf_counter {
 354 #ifdef CONFIG_PERF_COUNTERS
 355         union {
 356                 struct { /* hardware */
 357                         u64                             config;
 358                         unsigned long                   config_base;
 359                         unsigned long                   counter_base;
 360                         int                             idx;
 361                 };
 362                 union { /* software */
 363                         atomic64_t                      count;
 364                         struct hrtimer                  hrtimer;
 365                 };
 366         };
 367         atomic64_t                      prev_count;
 368         u64                             sample_period;
 369         u64                             last_period;
 370         atomic64_t                      period_left;
 371         u64                             interrupts;
 372
 373         u64                             freq_count;
 374         u64                             freq_interrupts;
 375         u64                             freq_stamp;
 376 #endif
 377 };
 378
 379 struct perf_counter;
 380
 381 /**
 382  * struct pmu - generic performance monitoring unit
 383  */
 384 struct pmu {
 385         int (*enable)                   (struct perf_counter *counter);
 386         void (*disable)                 (struct perf_counter *counter);
 387         void (*read)                    (struct perf_counter *counter);
 388         void (*unthrottle)              (struct perf_counter *counter);
 389 };
 390
 391 /**
 392  * enum perf_counter_active_state - the states of a counter
 393  */
 394 enum perf_counter_active_state {
 395         PERF_COUNTER_STATE_ERROR        = -2,
 396         PERF_COUNTER_STATE_OFF          = -1,
 397         PERF_COUNTER_STATE_INACTIVE     =  0,
 398         PERF_COUNTER_STATE_ACTIVE       =  1,
 399 };
 400
 401 struct file;
 402
 403 struct perf_mmap_data {
 404         struct rcu_head                 rcu_head;
 405         int                             nr_pages;       /* nr of data pages  */
 406         int                             nr_locked;      /* nr pages mlocked  */
 407
 408         atomic_t                        poll;           /* POLL_ for wakeups */
 409         atomic_t                        events;         /* event limit       */
 410
 411         atomic_long_t                   head;           /* write position    */
 412         atomic_long_t                   done_head;      /* completed head    */
 413
 414         atomic_t                        lock;           /* concurrent writes */
 415
 416         atomic_t                        wakeup;         /* needs a wakeup    */
 417
 418         struct perf_counter_mmap_page   *user_page;
 419         void                            *data_pages[0];
 420 };
 421
 422 struct perf_pending_entry {
 423         struct perf_pending_entry *next;
 424         void (*func)(struct perf_pending_entry *);
 425 };
 426
 427 /**
 428  * struct perf_counter - performance counter kernel representation:
 429  */
 430 struct perf_counter {
 431 #ifdef CONFIG_PERF_COUNTERS
 432         struct list_head                list_entry;
 433         struct list_head                event_entry;
 434         struct list_head                sibling_list;
 435         int                             nr_siblings;
 436         struct perf_counter             *group_leader;
 437         const struct pmu                *pmu;
 438
 439         enum perf_counter_active_state  state;
 440         atomic64_t                      count;
 441
 442         /*
 443          * These are the total time in nanoseconds that the counter
 444          * has been enabled (i.e. eligible to run, and the task has
 445          * been scheduled in, if this is a per-task counter)
 446          * and running (scheduled onto the CPU), respectively.
 447          *
 448          * They are computed from tstamp_enabled, tstamp_running and
 449          * tstamp_stopped when the counter is in INACTIVE or ACTIVE state.
 450          */
 451         u64                             total_time_enabled;
 452         u64                             total_time_running;
 453
 454         /*
 455          * These are timestamps used for computing total_time_enabled
 456          * and total_time_running when the counter is in INACTIVE or
 457          * ACTIVE state, measured in nanoseconds from an arbitrary point
 458          * in time.
 459          * tstamp_enabled: the notional time when the counter was enabled
 460          * tstamp_running: the notional time when the counter was scheduled on
 461          * tstamp_stopped: in INACTIVE state, the notional time when the
 462          *      counter was scheduled off.
 463          */
 464         u64                             tstamp_enabled;
 465         u64                             tstamp_running;
 466         u64                             tstamp_stopped;
 467
 468         struct perf_counter_attr        attr;
 469         struct hw_perf_counter          hw;
 470
 471         struct perf_counter_context     *ctx;
 472         struct file                     *filp;
 473
 474         /*
 475          * These accumulate total time (in nanoseconds) that children
 476          * counters have been enabled and running, respectively.
 477          */
 478         atomic64_t                      child_total_time_enabled;
 479         atomic64_t                      child_total_time_running;
 480
 481         /*
 482          * Protect attach/detach and child_list:
 483          */
 484         struct mutex                    child_mutex;
 485         struct list_head                child_list;
 486         struct perf_counter             *parent;
 487
 488         int                             oncpu;
 489         int                             cpu;
 490
 491         struct list_head                owner_entry;
 492         struct task_struct              *owner;
 493
 494         /* mmap bits */
 495         struct mutex                    mmap_mutex;
 496         atomic_t                        mmap_count;
 497         struct perf_mmap_data           *data;
 498
 499         /* poll related */
 500         wait_queue_head_t               waitq;
 501         struct fasync_struct            *fasync;
 502
 503         /* delayed work for NMIs and such */
 504         int                             pending_wakeup;
 505         int                             pending_kill;
 506         int                             pending_disable;
 507         struct perf_pending_entry       pending;
 508
 509         atomic_t                        event_limit;
 510
 511         void (*destroy)(struct perf_counter *);
 512         struct rcu_head                 rcu_head;
 513
 514         struct pid_namespace            *ns;
 515         u64                             id;
 516 #endif
 517 };
 518
 519 /**
 520  * struct perf_counter_context - counter context structure
 521  *
 522  * Used as a container for task counters and CPU counters as well:
 523  */
 524 struct perf_counter_context {
 525         /*
 526          * Protect the states of the counters in the list,
 527          * nr_active, and the list:
 528          */
 529         spinlock_t              lock;
 530         /*
 531          * Protect the list of counters.  Locking either mutex or lock
 532          * is sufficient to ensure the list doesn't change; to change
 533          * the list you need to lock both the mutex and the spinlock.
 534          */
 535         struct mutex            mutex;
 536
 537         struct list_head        counter_list;
 538         struct list_head        event_list;
 539         int                     nr_counters;
 540         int                     nr_active;
 541         int                     is_active;
 542         atomic_t                refcount;
 543         struct task_struct      *task;
 544
 545         /*
 546          * Context clock, runs when context enabled.
 547          */
 548         u64                     time;
 549         u64                     timestamp;
 550
 551         /*
 552          * These fields let us detect when two contexts have both
 553          * been cloned (inherited) from a common ancestor.
 554          */
 555         struct perf_counter_context *parent_ctx;
 556         u64                     parent_gen;
 557         u64                     generation;
 558         int                     pin_count;
 559         struct rcu_head         rcu_head;
 560 };
 561
 562 /**
 563  * struct perf_counter_cpu_context - per cpu counter context structure
 564  */
 565 struct perf_cpu_context {
 566         struct perf_counter_context     ctx;
 567         struct perf_counter_context     *task_ctx;
 568         int                             active_oncpu;
 569         int                             max_pertask;
 570         int                             exclusive;
 571
 572         /*
 573          * Recursion avoidance:
 574          *
 575          * task, softirq, irq, nmi context
 576          */
 577         int                             recursion[4];
 578 };
 579
 580 #ifdef CONFIG_PERF_COUNTERS
 581
 582 /*
 583  * Set by architecture code:
 584  */
 585 extern int perf_max_counters;
 586
 587 extern const struct pmu *hw_perf_counter_init(struct perf_counter *counter);
 588
 589 extern void perf_counter_task_sched_in(struct task_struct *task, int cpu);
 590 extern void perf_counter_task_sched_out(struct task_struct *task,
 591                                         struct task_struct *next, int cpu);
 592 extern void perf_counter_task_tick(struct task_struct *task, int cpu);
 593 extern int perf_counter_init_task(struct task_struct *child);
 594 extern void perf_counter_exit_task(struct task_struct *child);
 595 extern void perf_counter_free_task(struct task_struct *task);
 596 extern void perf_counter_do_pending(void);
 597 extern void perf_counter_print_debug(void);
 598 extern void __perf_disable(void);
 599 extern bool __perf_enable(void);
 600 extern void perf_disable(void);
 601 extern void perf_enable(void);
 602 extern int perf_counter_task_disable(void);
 603 extern int perf_counter_task_enable(void);
 604 extern int hw_perf_group_sched_in(struct perf_counter *group_leader,
 605                struct perf_cpu_context *cpuctx,
 606                struct perf_counter_context *ctx, int cpu);
 607 extern void perf_counter_update_userpage(struct perf_counter *counter);
 608
 609 struct perf_sample_data {
 610         struct pt_regs          *regs;
 611         u64                     addr;
 612         u64                     period;
 613 };
 614
 615 extern int perf_counter_overflow(struct perf_counter *counter, int nmi,
 616                                  struct perf_sample_data *data);
 617
 618 /*
 619  * Return 1 for a software counter, 0 for a hardware counter
 620  */
 621 static inline int is_software_counter(struct perf_counter *counter)
 622 {
 623         return (counter->attr.type != PERF_TYPE_RAW) &&
 624                 (counter->attr.type != PERF_TYPE_HARDWARE);
 625 }
 626
 627 extern void perf_swcounter_event(u32, u64, int, struct pt_regs *, u64);
 628
 629 extern void __perf_counter_mmap(struct vm_area_struct *vma);
 630
 631 static inline void perf_counter_mmap(struct vm_area_struct *vma)
 632 {
 633         if (vma->vm_flags & VM_EXEC)
 634                 __perf_counter_mmap(vma);
 635 }
 636
 637 extern void perf_counter_comm(struct task_struct *tsk);
 638 extern void perf_counter_fork(struct task_struct *tsk);
 639
 640 extern void perf_counter_task_migration(struct task_struct *task, int cpu);
 641
 642 #define MAX_STACK_DEPTH         255
 643
 644 struct perf_callchain_entry {
 645         u16     nr, hv, kernel, user;
 646         u64     ip[MAX_STACK_DEPTH];
 647 };
 648
 649 extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
 650
 651 extern int sysctl_perf_counter_paranoid;
 652 extern int sysctl_perf_counter_mlock;
 653 extern int sysctl_perf_counter_limit;
 654
 655 extern void perf_counter_init(void);
 656
 657 #ifndef perf_misc_flags
 658 #define perf_misc_flags(regs)   (user_mode(regs) ? PERF_EVENT_MISC_USER : \
 659                                  PERF_EVENT_MISC_KERNEL)
 660 #define perf_instruction_pointer(regs)  instruction_pointer(regs)
 661 #endif
 662
 663 #else
 664 static inline void
 665 perf_counter_task_sched_in(struct task_struct *task, int cpu)           { }
 666 static inline void
 667 perf_counter_task_sched_out(struct task_struct *task,
 668                             struct task_struct *next, int cpu)          { }
 669 static inline void
 670 perf_counter_task_tick(struct task_struct *task, int cpu)               { }
 671 static inline int perf_counter_init_task(struct task_struct *child)     { return 0; }
 672 static inline void perf_counter_exit_task(struct task_struct *child)    { }
 673 static inline void perf_counter_free_task(struct task_struct *task)     { }
 674 static inline void perf_counter_do_pending(void)                        { }
 675 static inline void perf_counter_print_debug(void)                       { }
 676 static inline void perf_disable(void)                                   { }
 677 static inline void perf_enable(void)                                    { }
 678 static inline int perf_counter_task_disable(void)       { return -EINVAL; }
 679 static inline int perf_counter_task_enable(void)        { return -EINVAL; }
 680
 681 static inline void
 682 perf_swcounter_event(u32 event, u64 nr, int nmi,
 683                      struct pt_regs *regs, u64 addr)                    { }
 684
 685 static inline void perf_counter_mmap(struct vm_area_struct *vma)        { }
 686 static inline void perf_counter_comm(struct task_struct *tsk)           { }
 687 static inline void perf_counter_fork(struct task_struct *tsk)           { }
 688 static inline void perf_counter_init(void)                              { }
 689 static inline void perf_counter_task_migration(struct task_struct *task,
 690                                                int cpu)                 { }
 691 #endif
 692
 693 #endif /* __KERNEL__ */
 694 #endif /* _LINUX_PERF_COUNTER_H */