tools/perf/util/evlist.c

   1 /*
   2  * Copyright (C) 2011, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
   3  *
   4  * Parts came from builtin-{top,stat,record}.c, see those files for further
   5  * copyright notes.
   6  *
   7  * Released under the GPL v2. (and only v2, not any later version)
   8  */
   9 #include "util.h"
  10 #include <api/fs/debugfs.h>
  11 #include <poll.h>
  12 #include "cpumap.h"
  13 #include "thread_map.h"
  14 #include "target.h"
  15 #include "evlist.h"
  16 #include "evsel.h"
  17 #include "debug.h"
  18 #include <unistd.h>
  19
  20 #include "parse-events.h"
  21 #include "parse-options.h"
  22
  23 #include <sys/mman.h>
  24
  25 #include <linux/bitops.h>
  26 #include <linux/hash.h>
  27
  28 static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx);
  29 static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx);
  30
  31 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
  32 #define SID(e, x, y) xyarray__entry(e->sample_id, x, y)
  33
  34 void perf_evlist__init(struct perf_evlist *evlist, struct cpu_map *cpus,
  35                        struct thread_map *threads)
  36 {
  37         int i;
  38
  39         for (i = 0; i < PERF_EVLIST__HLIST_SIZE; ++i)
  40                 INIT_HLIST_HEAD(&evlist->heads[i]);
  41         INIT_LIST_HEAD(&evlist->entries);
  42         perf_evlist__set_maps(evlist, cpus, threads);
  43         fdarray__init(&evlist->pollfd, 64);
  44         evlist->workload.pid = -1;
  45 }
  46
  47 struct perf_evlist *perf_evlist__new(void)
  48 {
  49         struct perf_evlist *evlist = zalloc(sizeof(*evlist));
  50
  51         if (evlist != NULL)
  52                 perf_evlist__init(evlist, NULL, NULL);
  53
  54         return evlist;
  55 }
  56
  57 struct perf_evlist *perf_evlist__new_default(void)
  58 {
  59         struct perf_evlist *evlist = perf_evlist__new();
  60
  61         if (evlist && perf_evlist__add_default(evlist)) {
  62                 perf_evlist__delete(evlist);
  63                 evlist = NULL;
  64         }
  65
  66         return evlist;
  67 }
  68
  69 /**
  70  * perf_evlist__set_id_pos - set the positions of event ids.
  71  * @evlist: selected event list
  72  *
  73  * Events with compatible sample types all have the same id_pos
  74  * and is_pos.  For convenience, put a copy on evlist.
  75  */
  76 void perf_evlist__set_id_pos(struct perf_evlist *evlist)
  77 {
  78         struct perf_evsel *first = perf_evlist__first(evlist);
  79
  80         evlist->id_pos = first->id_pos;
  81         evlist->is_pos = first->is_pos;
  82 }
  83
  84 static void perf_evlist__update_id_pos(struct perf_evlist *evlist)
  85 {
  86         struct perf_evsel *evsel;
  87
  88         evlist__for_each(evlist, evsel)
  89                 perf_evsel__calc_id_pos(evsel);
  90
  91         perf_evlist__set_id_pos(evlist);
  92 }
  93
  94 static void perf_evlist__purge(struct perf_evlist *evlist)
  95 {
  96         struct perf_evsel *pos, *n;
  97
  98         evlist__for_each_safe(evlist, n, pos) {
  99                 list_del_init(&pos->node);
 100                 perf_evsel__delete(pos);
 101         }
 102
 103         evlist->nr_entries = 0;
 104 }
 105
 106 void perf_evlist__exit(struct perf_evlist *evlist)
 107 {
 108         zfree(&evlist->mmap);
 109         fdarray__exit(&evlist->pollfd);
 110 }
 111
 112 void perf_evlist__delete(struct perf_evlist *evlist)
 113 {
 114         perf_evlist__munmap(evlist);
 115         perf_evlist__close(evlist);
 116         cpu_map__delete(evlist->cpus);
 117         thread_map__delete(evlist->threads);
 118         evlist->cpus = NULL;
 119         evlist->threads = NULL;
 120         perf_evlist__purge(evlist);
 121         perf_evlist__exit(evlist);
 122         free(evlist);
 123 }
 124
 125 void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry)
 126 {
 127         list_add_tail(&entry->node, &evlist->entries);
 128         entry->idx = evlist->nr_entries;
 129         entry->tracking = !entry->idx;
 130
 131         if (!evlist->nr_entries++)
 132                 perf_evlist__set_id_pos(evlist);
 133 }
 134
 135 void perf_evlist__splice_list_tail(struct perf_evlist *evlist,
 136                                    struct list_head *list,
 137                                    int nr_entries)
 138 {
 139         bool set_id_pos = !evlist->nr_entries;
 140
 141         list_splice_tail(list, &evlist->entries);
 142         evlist->nr_entries += nr_entries;
 143         if (set_id_pos)
 144                 perf_evlist__set_id_pos(evlist);
 145 }
 146
 147 void __perf_evlist__set_leader(struct list_head *list)
 148 {
 149         struct perf_evsel *evsel, *leader;
 150
 151         leader = list_entry(list->next, struct perf_evsel, node);
 152         evsel = list_entry(list->prev, struct perf_evsel, node);
 153
 154         leader->nr_members = evsel->idx - leader->idx + 1;
 155
 156         __evlist__for_each(list, evsel) {
 157                 evsel->leader = leader;
 158         }
 159 }
 160
 161 void perf_evlist__set_leader(struct perf_evlist *evlist)
 162 {
 163         if (evlist->nr_entries) {
 164                 evlist->nr_groups = evlist->nr_entries > 1 ? 1 : 0;
 165                 __perf_evlist__set_leader(&evlist->entries);
 166         }
 167 }
 168
 169 int perf_evlist__add_default(struct perf_evlist *evlist)
 170 {
 171         struct perf_event_attr attr = {
 172                 .type = PERF_TYPE_HARDWARE,
 173                 .config = PERF_COUNT_HW_CPU_CYCLES,
 174         };
 175         struct perf_evsel *evsel;
 176
 177         event_attr_init(&attr);
 178
 179         evsel = perf_evsel__new(&attr);
 180         if (evsel == NULL)
 181                 goto error;
 182
 183         /* use strdup() because free(evsel) assumes name is allocated */
 184         evsel->name = strdup("cycles");
 185         if (!evsel->name)
 186                 goto error_free;
 187
 188         perf_evlist__add(evlist, evsel);
 189         return 0;
 190 error_free:
 191         perf_evsel__delete(evsel);
 192 error:
 193         return -ENOMEM;
 194 }
 195
 196 static int perf_evlist__add_attrs(struct perf_evlist *evlist,
 197                                   struct perf_event_attr *attrs, size_t nr_attrs)
 198 {
 199         struct perf_evsel *evsel, *n;
 200         LIST_HEAD(head);
 201         size_t i;
 202
 203         for (i = 0; i < nr_attrs; i++) {
 204                 evsel = perf_evsel__new_idx(attrs + i, evlist->nr_entries + i);
 205                 if (evsel == NULL)
 206                         goto out_delete_partial_list;
 207                 list_add_tail(&evsel->node, &head);
 208         }
 209
 210         perf_evlist__splice_list_tail(evlist, &head, nr_attrs);
 211
 212         return 0;
 213
 214 out_delete_partial_list:
 215         __evlist__for_each_safe(&head, n, evsel)
 216                 perf_evsel__delete(evsel);
 217         return -1;
 218 }
 219
 220 int __perf_evlist__add_default_attrs(struct perf_evlist *evlist,
 221                                      struct perf_event_attr *attrs, size_t nr_attrs)
 222 {
 223         size_t i;
 224
 225         for (i = 0; i < nr_attrs; i++)
 226                 event_attr_init(attrs + i);
 227
 228         return perf_evlist__add_attrs(evlist, attrs, nr_attrs);
 229 }
 230
 231 struct perf_evsel *
 232 perf_evlist__find_tracepoint_by_id(struct perf_evlist *evlist, int id)
 233 {
 234         struct perf_evsel *evsel;
 235
 236         evlist__for_each(evlist, evsel) {
 237                 if (evsel->attr.type   == PERF_TYPE_TRACEPOINT &&
 238                     (int)evsel->attr.config == id)
 239                         return evsel;
 240         }
 241
 242         return NULL;
 243 }
 244
 245 struct perf_evsel *
 246 perf_evlist__find_tracepoint_by_name(struct perf_evlist *evlist,
 247                                      const char *name)
 248 {
 249         struct perf_evsel *evsel;
 250
 251         evlist__for_each(evlist, evsel) {
 252                 if ((evsel->attr.type == PERF_TYPE_TRACEPOINT) &&
 253                     (strcmp(evsel->name, name) == 0))
 254                         return evsel;
 255         }
 256
 257         return NULL;
 258 }
 259
 260 int perf_evlist__add_newtp(struct perf_evlist *evlist,
 261                            const char *sys, const char *name, void *handler)
 262 {
 263         struct perf_evsel *evsel = perf_evsel__newtp(sys, name);
 264
 265         if (evsel == NULL)
 266                 return -1;
 267
 268         evsel->handler = handler;
 269         perf_evlist__add(evlist, evsel);
 270         return 0;
 271 }
 272
 273 static int perf_evlist__nr_threads(struct perf_evlist *evlist,
 274                                    struct perf_evsel *evsel)
 275 {
 276         if (evsel->system_wide)
 277                 return 1;
 278         else
 279                 return thread_map__nr(evlist->threads);
 280 }
 281
 282 void perf_evlist__disable(struct perf_evlist *evlist)
 283 {
 284         int cpu, thread;
 285         struct perf_evsel *pos;
 286         int nr_cpus = cpu_map__nr(evlist->cpus);
 287         int nr_threads;
 288
 289         for (cpu = 0; cpu < nr_cpus; cpu++) {
 290                 evlist__for_each(evlist, pos) {
 291                         if (!perf_evsel__is_group_leader(pos) || !pos->fd)
 292                                 continue;
 293                         nr_threads = perf_evlist__nr_threads(evlist, pos);
 294                         for (thread = 0; thread < nr_threads; thread++)
 295                                 ioctl(FD(pos, cpu, thread),
 296                                       PERF_EVENT_IOC_DISABLE, 0);
 297                 }
 298         }
 299 }
 300
 301 void perf_evlist__enable(struct perf_evlist *evlist)
 302 {
 303         int cpu, thread;
 304         struct perf_evsel *pos;
 305         int nr_cpus = cpu_map__nr(evlist->cpus);
 306         int nr_threads;
 307
 308         for (cpu = 0; cpu < nr_cpus; cpu++) {
 309                 evlist__for_each(evlist, pos) {
 310                         if (!perf_evsel__is_group_leader(pos) || !pos->fd)
 311                                 continue;
 312                         nr_threads = perf_evlist__nr_threads(evlist, pos);
 313                         for (thread = 0; thread < nr_threads; thread++)
 314                                 ioctl(FD(pos, cpu, thread),
 315                                       PERF_EVENT_IOC_ENABLE, 0);
 316                 }
 317         }
 318 }
 319
 320 int perf_evlist__disable_event(struct perf_evlist *evlist,
 321                                struct perf_evsel *evsel)
 322 {
 323         int cpu, thread, err;
 324         int nr_cpus = cpu_map__nr(evlist->cpus);
 325         int nr_threads = perf_evlist__nr_threads(evlist, evsel);
 326
 327         if (!evsel->fd)
 328                 return 0;
 329
 330         for (cpu = 0; cpu < nr_cpus; cpu++) {
 331                 for (thread = 0; thread < nr_threads; thread++) {
 332                         err = ioctl(FD(evsel, cpu, thread),
 333                                     PERF_EVENT_IOC_DISABLE, 0);
 334                         if (err)
 335                                 return err;
 336                 }
 337         }
 338         return 0;
 339 }
 340
 341 int perf_evlist__enable_event(struct perf_evlist *evlist,
 342                               struct perf_evsel *evsel)
 343 {
 344         int cpu, thread, err;
 345         int nr_cpus = cpu_map__nr(evlist->cpus);
 346         int nr_threads = perf_evlist__nr_threads(evlist, evsel);
 347
 348         if (!evsel->fd)
 349                 return -EINVAL;
 350
 351         for (cpu = 0; cpu < nr_cpus; cpu++) {
 352                 for (thread = 0; thread < nr_threads; thread++) {
 353                         err = ioctl(FD(evsel, cpu, thread),
 354                                     PERF_EVENT_IOC_ENABLE, 0);
 355                         if (err)
 356                                 return err;
 357                 }
 358         }
 359         return 0;
 360 }
 361
 362 static int perf_evlist__enable_event_cpu(struct perf_evlist *evlist,
 363                                          struct perf_evsel *evsel, int cpu)
 364 {
 365         int thread, err;
 366         int nr_threads = perf_evlist__nr_threads(evlist, evsel);
 367
 368         if (!evsel->fd)
 369                 return -EINVAL;
 370
 371         for (thread = 0; thread < nr_threads; thread++) {
 372                 err = ioctl(FD(evsel, cpu, thread),
 373                             PERF_EVENT_IOC_ENABLE, 0);
 374                 if (err)
 375                         return err;
 376         }
 377         return 0;
 378 }
 379
 380 static int perf_evlist__enable_event_thread(struct perf_evlist *evlist,
 381                                             struct perf_evsel *evsel,
 382                                             int thread)
 383 {
 384         int cpu, err;
 385         int nr_cpus = cpu_map__nr(evlist->cpus);
 386
 387         if (!evsel->fd)
 388                 return -EINVAL;
 389
 390         for (cpu = 0; cpu < nr_cpus; cpu++) {
 391                 err = ioctl(FD(evsel, cpu, thread), PERF_EVENT_IOC_ENABLE, 0);
 392                 if (err)
 393                         return err;
 394         }
 395         return 0;
 396 }
 397
 398 int perf_evlist__enable_event_idx(struct perf_evlist *evlist,
 399                                   struct perf_evsel *evsel, int idx)
 400 {
 401         bool per_cpu_mmaps = !cpu_map__empty(evlist->cpus);
 402
 403         if (per_cpu_mmaps)
 404                 return perf_evlist__enable_event_cpu(evlist, evsel, idx);
 405         else
 406                 return perf_evlist__enable_event_thread(evlist, evsel, idx);
 407 }
 408
 409 int perf_evlist__alloc_pollfd(struct perf_evlist *evlist)
 410 {
 411         int nr_cpus = cpu_map__nr(evlist->cpus);
 412         int nr_threads = thread_map__nr(evlist->threads);
 413         int nfds = 0;
 414         struct perf_evsel *evsel;
 415
 416         list_for_each_entry(evsel, &evlist->entries, node) {
 417                 if (evsel->system_wide)
 418                         nfds += nr_cpus;
 419                 else
 420                         nfds += nr_cpus * nr_threads;
 421         }
 422
 423         if (fdarray__available_entries(&evlist->pollfd) < nfds &&
 424             fdarray__grow(&evlist->pollfd, nfds) < 0)
 425                 return -ENOMEM;
 426
 427         return 0;
 428 }
 429
 430 static int __perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd, int idx)
 431 {
 432         int pos = fdarray__add(&evlist->pollfd, fd, POLLIN | POLLERR | POLLHUP);
 433         /*
 434          * Save the idx so that when we filter out fds POLLHUP'ed we can
 435          * close the associated evlist->mmap[] entry.
 436          */
 437         if (pos >= 0) {
 438                 evlist->pollfd.priv[pos].idx = idx;
 439
 440                 fcntl(fd, F_SETFL, O_NONBLOCK);
 441         }
 442
 443         return pos;
 444 }
 445
 446 int perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd)
 447 {
 448         return __perf_evlist__add_pollfd(evlist, fd, -1);
 449 }
 450
 451 static void perf_evlist__munmap_filtered(struct fdarray *fda, int fd)
 452 {
 453         struct perf_evlist *evlist = container_of(fda, struct perf_evlist, pollfd);
 454
 455         perf_evlist__mmap_put(evlist, fda->priv[fd].idx);
 456 }
 457
 458 int perf_evlist__filter_pollfd(struct perf_evlist *evlist, short revents_and_mask)
 459 {
 460         return fdarray__filter(&evlist->pollfd, revents_and_mask,
 461                                perf_evlist__munmap_filtered);
 462 }
 463
 464 int perf_evlist__poll(struct perf_evlist *evlist, int timeout)
 465 {
 466         return fdarray__poll(&evlist->pollfd, timeout);
 467 }
 468
 469 static void perf_evlist__id_hash(struct perf_evlist *evlist,
 470                                  struct perf_evsel *evsel,
 471                                  int cpu, int thread, u64 id)
 472 {
 473         int hash;
 474         struct perf_sample_id *sid = SID(evsel, cpu, thread);
 475
 476         sid->id = id;
 477         sid->evsel = evsel;
 478         hash = hash_64(sid->id, PERF_EVLIST__HLIST_BITS);
 479         hlist_add_head(&sid->node, &evlist->heads[hash]);
 480 }
 481
 482 void perf_evlist__id_add(struct perf_evlist *evlist, struct perf_evsel *evsel,
 483                          int cpu, int thread, u64 id)
 484 {
 485         perf_evlist__id_hash(evlist, evsel, cpu, thread, id);
 486         evsel->id[evsel->ids++] = id;
 487 }
 488
 489 static int perf_evlist__id_add_fd(struct perf_evlist *evlist,
 490                                   struct perf_evsel *evsel,
 491                                   int cpu, int thread, int fd)
 492 {
 493         u64 read_data[4] = { 0, };
 494         int id_idx = 1; /* The first entry is the counter value */
 495         u64 id;
 496         int ret;
 497
 498         ret = ioctl(fd, PERF_EVENT_IOC_ID, &id);
 499         if (!ret)
 500                 goto add;
 501
 502         if (errno != ENOTTY)
 503                 return -1;
 504
 505         /* Legacy way to get event id.. All hail to old kernels! */
 506
 507         /*
 508          * This way does not work with group format read, so bail
 509          * out in that case.
 510          */
 511         if (perf_evlist__read_format(evlist) & PERF_FORMAT_GROUP)
 512                 return -1;
 513
 514         if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
 515             read(fd, &read_data, sizeof(read_data)) == -1)
 516                 return -1;
 517
 518         if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
 519                 ++id_idx;
 520         if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
 521                 ++id_idx;
 522
 523         id = read_data[id_idx];
 524
 525  add:
 526         perf_evlist__id_add(evlist, evsel, cpu, thread, id);
 527         return 0;
 528 }
 529
 530 struct perf_sample_id *perf_evlist__id2sid(struct perf_evlist *evlist, u64 id)
 531 {
 532         struct hlist_head *head;
 533         struct perf_sample_id *sid;
 534         int hash;
 535
 536         hash = hash_64(id, PERF_EVLIST__HLIST_BITS);
 537         head = &evlist->heads[hash];
 538
 539         hlist_for_each_entry(sid, head, node)
 540                 if (sid->id == id)
 541                         return sid;
 542
 543         return NULL;
 544 }
 545
 546 struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
 547 {
 548         struct perf_sample_id *sid;
 549
 550         if (evlist->nr_entries == 1)
 551                 return perf_evlist__first(evlist);
 552
 553         sid = perf_evlist__id2sid(evlist, id);
 554         if (sid)
 555                 return sid->evsel;
 556
 557         if (!perf_evlist__sample_id_all(evlist))
 558                 return perf_evlist__first(evlist);
 559
 560         return NULL;
 561 }
 562
 563 static int perf_evlist__event2id(struct perf_evlist *evlist,
 564                                  union perf_event *event, u64 *id)
 565 {
 566         const u64 *array = event->sample.array;
 567         ssize_t n;
 568
 569         n = (event->header.size - sizeof(event->header)) >> 3;
 570
 571         if (event->header.type == PERF_RECORD_SAMPLE) {
 572                 if (evlist->id_pos >= n)
 573                         return -1;
 574                 *id = array[evlist->id_pos];
 575         } else {
 576                 if (evlist->is_pos > n)
 577                         return -1;
 578                 n -= evlist->is_pos;
 579                 *id = array[n];
 580         }
 581         return 0;
 582 }
 583
 584 static struct perf_evsel *perf_evlist__event2evsel(struct perf_evlist *evlist,
 585                                                    union perf_event *event)
 586 {
 587         struct perf_evsel *first = perf_evlist__first(evlist);
 588         struct hlist_head *head;
 589         struct perf_sample_id *sid;
 590         int hash;
 591         u64 id;
 592
 593         if (evlist->nr_entries == 1)
 594                 return first;
 595
 596         if (!first->attr.sample_id_all &&
 597             event->header.type != PERF_RECORD_SAMPLE)
 598                 return first;
 599
 600         if (perf_evlist__event2id(evlist, event, &id))
 601                 return NULL;
 602
 603         /* Synthesized events have an id of zero */
 604         if (!id)
 605                 return first;
 606
 607         hash = hash_64(id, PERF_EVLIST__HLIST_BITS);
 608         head = &evlist->heads[hash];
 609
 610         hlist_for_each_entry(sid, head, node) {
 611                 if (sid->id == id)
 612                         return sid->evsel;
 613         }
 614         return NULL;
 615 }
 616
 617 union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx)
 618 {
 619         struct perf_mmap *md = &evlist->mmap[idx];
 620         unsigned int head = perf_mmap__read_head(md);
 621         unsigned int old = md->prev;
 622         unsigned char *data = md->base + page_size;
 623         union perf_event *event = NULL;
 624
 625         if (evlist->overwrite) {
 626                 /*
 627                  * If we're further behind than half the buffer, there's a chance
 628                  * the writer will bite our tail and mess up the samples under us.
 629                  *
 630                  * If we somehow ended up ahead of the head, we got messed up.
 631                  *
 632                  * In either case, truncate and restart at head.
 633                  */
 634                 int diff = head - old;
 635                 if (diff > md->mask / 2 || diff < 0) {
 636                         fprintf(stderr, "WARNING: failed to keep up with mmap data.\n");
 637
 638                         /*
 639                          * head points to a known good entry, start there.
 640                          */
 641                         old = head;
 642                 }
 643         }
 644
 645         if (old != head) {
 646                 size_t size;
 647
 648                 event = (union perf_event *)&data[old & md->mask];
 649                 size = event->header.size;
 650
 651                 /*
 652                  * Event straddles the mmap boundary -- header should always
 653                  * be inside due to u64 alignment of output.
 654                  */
 655                 if ((old & md->mask) + size != ((old + size) & md->mask)) {
 656                         unsigned int offset = old;
 657                         unsigned int len = min(sizeof(*event), size), cpy;
 658                         void *dst = md->event_copy;
 659
 660                         do {
 661                                 cpy = min(md->mask + 1 - (offset & md->mask), len);
 662                                 memcpy(dst, &data[offset & md->mask], cpy);
 663                                 offset += cpy;
 664                                 dst += cpy;
 665                                 len -= cpy;
 666                         } while (len);
 667
 668                         event = (union perf_event *) md->event_copy;
 669                 }
 670
 671                 old += size;
 672         }
 673
 674         md->prev = old;
 675
 676         return event;
 677 }
 678
 679 static bool perf_mmap__empty(struct perf_mmap *md)
 680 {
 681         return perf_mmap__read_head(md) != md->prev;
 682 }
 683
 684 static void perf_evlist__mmap_get(struct perf_evlist *evlist, int idx)
 685 {
 686         ++evlist->mmap[idx].refcnt;
 687 }
 688
 689 static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx)
 690 {
 691         BUG_ON(evlist->mmap[idx].refcnt == 0);
 692
 693         if (--evlist->mmap[idx].refcnt == 0)
 694                 __perf_evlist__munmap(evlist, idx);
 695 }
 696
 697 void perf_evlist__mmap_consume(struct perf_evlist *evlist, int idx)
 698 {
 699         struct perf_mmap *md = &evlist->mmap[idx];
 700
 701         if (!evlist->overwrite) {
 702                 unsigned int old = md->prev;
 703
 704                 perf_mmap__write_tail(md, old);
 705         }
 706
 707         if (md->refcnt == 1 && perf_mmap__empty(md))
 708                 perf_evlist__mmap_put(evlist, idx);
 709 }
 710
 711 static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx)
 712 {
 713         if (evlist->mmap[idx].base != NULL) {
 714                 munmap(evlist->mmap[idx].base, evlist->mmap_len);
 715                 evlist->mmap[idx].base = NULL;
 716                 evlist->mmap[idx].refcnt = 0;
 717         }
 718 }
 719
 720 void perf_evlist__munmap(struct perf_evlist *evlist)
 721 {
 722         int i;
 723
 724         if (evlist->mmap == NULL)
 725                 return;
 726
 727         for (i = 0; i < evlist->nr_mmaps; i++)
 728                 __perf_evlist__munmap(evlist, i);
 729
 730         zfree(&evlist->mmap);
 731 }
 732
 733 static int perf_evlist__alloc_mmap(struct perf_evlist *evlist)
 734 {
 735         evlist->nr_mmaps = cpu_map__nr(evlist->cpus);
 736         if (cpu_map__empty(evlist->cpus))
 737                 evlist->nr_mmaps = thread_map__nr(evlist->threads);
 738         evlist->mmap = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
 739         return evlist->mmap != NULL ? 0 : -ENOMEM;
 740 }
 741
 742 struct mmap_params {
 743         int prot;
 744         int mask;
 745 };
 746
 747 static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
 748                                struct mmap_params *mp, int fd)
 749 {
 750         /*
 751          * The last one will be done at perf_evlist__mmap_consume(), so that we
 752          * make sure we don't prevent tools from consuming every last event in
 753          * the ring buffer.
 754          *
 755          * I.e. we can get the POLLHUP meaning that the fd doesn't exist
 756          * anymore, but the last events for it are still in the ring buffer,
 757          * waiting to be consumed.
 758          *
 759          * Tools can chose to ignore this at their own discretion, but the
 760          * evlist layer can't just drop it when filtering events in
 761          * perf_evlist__filter_pollfd().
 762          */
 763         evlist->mmap[idx].refcnt = 2;
 764         evlist->mmap[idx].prev = 0;
 765         evlist->mmap[idx].mask = mp->mask;
 766         evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, mp->prot,
 767                                       MAP_SHARED, fd, 0);
 768         if (evlist->mmap[idx].base == MAP_FAILED) {
 769                 pr_debug2("failed to mmap perf event ring buffer, error %d\n",
 770                           errno);
 771                 evlist->mmap[idx].base = NULL;
 772                 return -1;
 773         }
 774
 775         return 0;
 776 }
 777
 778 static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
 779                                        struct mmap_params *mp, int cpu,
 780                                        int thread, int *output)
 781 {
 782         struct perf_evsel *evsel;
 783
 784         evlist__for_each(evlist, evsel) {
 785                 int fd;
 786
 787                 if (evsel->system_wide && thread)
 788                         continue;
 789
 790                 fd = FD(evsel, cpu, thread);
 791
 792                 if (*output == -1) {
 793                         *output = fd;
 794                         if (__perf_evlist__mmap(evlist, idx, mp, *output) < 0)
 795                                 return -1;
 796                 } else {
 797                         if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, *output) != 0)
 798                                 return -1;
 799
 800                         perf_evlist__mmap_get(evlist, idx);
 801                 }
 802
 803                 if (__perf_evlist__add_pollfd(evlist, fd, idx) < 0) {
 804                         perf_evlist__mmap_put(evlist, idx);
 805                         return -1;
 806                 }
 807
 808                 if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
 809                     perf_evlist__id_add_fd(evlist, evsel, cpu, thread, fd) < 0)
 810                         return -1;
 811         }
 812
 813         return 0;
 814 }
 815
 816 static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist,
 817                                      struct mmap_params *mp)
 818 {
 819         int cpu, thread;
 820         int nr_cpus = cpu_map__nr(evlist->cpus);
 821         int nr_threads = thread_map__nr(evlist->threads);
 822
 823         pr_debug2("perf event ring buffer mmapped per cpu\n");
 824         for (cpu = 0; cpu < nr_cpus; cpu++) {
 825                 int output = -1;
 826
 827                 for (thread = 0; thread < nr_threads; thread++) {
 828                         if (perf_evlist__mmap_per_evsel(evlist, cpu, mp, cpu,
 829                                                         thread, &output))
 830                                 goto out_unmap;
 831                 }
 832         }
 833
 834         return 0;
 835
 836 out_unmap:
 837         for (cpu = 0; cpu < nr_cpus; cpu++)
 838                 __perf_evlist__munmap(evlist, cpu);
 839         return -1;
 840 }
 841
 842 static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist,
 843                                         struct mmap_params *mp)
 844 {
 845         int thread;
 846         int nr_threads = thread_map__nr(evlist->threads);
 847
 848         pr_debug2("perf event ring buffer mmapped per thread\n");
 849         for (thread = 0; thread < nr_threads; thread++) {
 850                 int output = -1;
 851
 852                 if (perf_evlist__mmap_per_evsel(evlist, thread, mp, 0, thread,
 853                                                 &output))
 854                         goto out_unmap;
 855         }
 856
 857         return 0;
 858
 859 out_unmap:
 860         for (thread = 0; thread < nr_threads; thread++)
 861                 __perf_evlist__munmap(evlist, thread);
 862         return -1;
 863 }
 864
 865 static size_t perf_evlist__mmap_size(unsigned long pages)
 866 {
 867         /* 512 kiB: default amount of unprivileged mlocked memory */
 868         if (pages == UINT_MAX)
 869                 pages = (512 * 1024) / page_size;
 870         else if (!is_power_of_2(pages))
 871                 return 0;
 872
 873         return (pages + 1) * page_size;
 874 }
 875
 876 static long parse_pages_arg(const char *str, unsigned long min,
 877                             unsigned long max)
 878 {
 879         unsigned long pages, val;
 880         static struct parse_tag tags[] = {
 881                 { .tag  = 'B', .mult = 1       },
 882                 { .tag  = 'K', .mult = 1 << 10 },
 883                 { .tag  = 'M', .mult = 1 << 20 },
 884                 { .tag  = 'G', .mult = 1 << 30 },
 885                 { .tag  = 0 },
 886         };
 887
 888         if (str == NULL)
 889                 return -EINVAL;
 890
 891         val = parse_tag_value(str, tags);
 892         if (val != (unsigned long) -1) {
 893                 /* we got file size value */
 894                 pages = PERF_ALIGN(val, page_size) / page_size;
 895         } else {
 896                 /* we got pages count value */
 897                 char *eptr;
 898                 pages = strtoul(str, &eptr, 10);
 899                 if (*eptr != '\0')
 900                         return -EINVAL;
 901         }
 902
 903         if (pages == 0 && min == 0) {
 904                 /* leave number of pages at 0 */
 905         } else if (!is_power_of_2(pages)) {
 906                 /* round pages up to next power of 2 */
 907                 pages = next_pow2_l(pages);
 908                 if (!pages)
 909                         return -EINVAL;
 910                 pr_info("rounding mmap pages size to %lu bytes (%lu pages)\n",
 911                         pages * page_size, pages);
 912         }
 913
 914         if (pages > max)
 915                 return -EINVAL;
 916
 917         return pages;
 918 }
 919
 920 int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str,
 921                                   int unset __maybe_unused)
 922 {
 923         unsigned int *mmap_pages = opt->value;
 924         unsigned long max = UINT_MAX;
 925         long pages;
 926
 927         if (max > SIZE_MAX / page_size)
 928                 max = SIZE_MAX / page_size;
 929
 930         pages = parse_pages_arg(str, 1, max);
 931         if (pages < 0) {
 932                 pr_err("Invalid argument for --mmap_pages/-m\n");
 933                 return -1;
 934         }
 935
 936         *mmap_pages = pages;
 937         return 0;
 938 }
 939
 940 /**
 941  * perf_evlist__mmap - Create mmaps to receive events.
 942  * @evlist: list of events
 943  * @pages: map length in pages
 944  * @overwrite: overwrite older events?
 945  *
 946  * If @overwrite is %false the user needs to signal event consumption using
 947  * perf_mmap__write_tail().  Using perf_evlist__mmap_read() does this
 948  * automatically.
 949  *
 950  * Return: %0 on success, negative error code otherwise.
 951  */
 952 int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
 953                       bool overwrite)
 954 {
 955         struct perf_evsel *evsel;
 956         const struct cpu_map *cpus = evlist->cpus;
 957         const struct thread_map *threads = evlist->threads;
 958         struct mmap_params mp = {
 959                 .prot = PROT_READ | (overwrite ? 0 : PROT_WRITE),
 960         };
 961
 962         if (evlist->mmap == NULL && perf_evlist__alloc_mmap(evlist) < 0)
 963                 return -ENOMEM;
 964
 965         if (evlist->pollfd.entries == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
 966                 return -ENOMEM;
 967
 968         evlist->overwrite = overwrite;
 969         evlist->mmap_len = perf_evlist__mmap_size(pages);
 970         pr_debug("mmap size %zuB\n", evlist->mmap_len);
 971         mp.mask = evlist->mmap_len - page_size - 1;
 972
 973         evlist__for_each(evlist, evsel) {
 974                 if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
 975                     evsel->sample_id == NULL &&
 976                     perf_evsel__alloc_id(evsel, cpu_map__nr(cpus), threads->nr) < 0)
 977                         return -ENOMEM;
 978         }
 979
 980         if (cpu_map__empty(cpus))
 981                 return perf_evlist__mmap_per_thread(evlist, &mp);
 982
 983         return perf_evlist__mmap_per_cpu(evlist, &mp);
 984 }
 985
 986 int perf_evlist__create_maps(struct perf_evlist *evlist, struct target *target)
 987 {
 988         evlist->threads = thread_map__new_str(target->pid, target->tid,
 989                                               target->uid);
 990
 991         if (evlist->threads == NULL)
 992                 return -1;
 993
 994         if (target__uses_dummy_map(target))
 995                 evlist->cpus = cpu_map__dummy_new();
 996         else
 997                 evlist->cpus = cpu_map__new(target->cpu_list);
 998
 999         if (evlist->cpus == NULL)
1000                 goto out_delete_threads;
1001
1002         return 0;
1003
1004 out_delete_threads:
1005         thread_map__delete(evlist->threads);
1006         return -1;
1007 }
1008
1009 int perf_evlist__apply_filters(struct perf_evlist *evlist)
1010 {
1011         struct perf_evsel *evsel;
1012         int err = 0;
1013         const int ncpus = cpu_map__nr(evlist->cpus),
1014                   nthreads = thread_map__nr(evlist->threads);
1015
1016         evlist__for_each(evlist, evsel) {
1017                 if (evsel->filter == NULL)
1018                         continue;
1019
1020                 err = perf_evsel__set_filter(evsel, ncpus, nthreads, evsel->filter);
1021                 if (err)
1022                         break;
1023         }
1024
1025         return err;
1026 }
1027
1028 int perf_evlist__set_filter(struct perf_evlist *evlist, const char *filter)
1029 {
1030         struct perf_evsel *evsel;
1031         int err = 0;
1032         const int ncpus = cpu_map__nr(evlist->cpus),
1033                   nthreads = thread_map__nr(evlist->threads);
1034
1035         evlist__for_each(evlist, evsel) {
1036                 err = perf_evsel__set_filter(evsel, ncpus, nthreads, filter);
1037                 if (err)
1038                         break;
1039         }
1040
1041         return err;
1042 }
1043
1044 bool perf_evlist__valid_sample_type(struct perf_evlist *evlist)
1045 {
1046         struct perf_evsel *pos;
1047
1048         if (evlist->nr_entries == 1)
1049                 return true;
1050
1051         if (evlist->id_pos < 0 || evlist->is_pos < 0)
1052                 return false;
1053
1054         evlist__for_each(evlist, pos) {
1055                 if (pos->id_pos != evlist->id_pos ||
1056                     pos->is_pos != evlist->is_pos)
1057                         return false;
1058         }
1059
1060         return true;
1061 }
1062
1063 u64 __perf_evlist__combined_sample_type(struct perf_evlist *evlist)
1064 {
1065         struct perf_evsel *evsel;
1066
1067         if (evlist->combined_sample_type)
1068                 return evlist->combined_sample_type;
1069
1070         evlist__for_each(evlist, evsel)
1071                 evlist->combined_sample_type |= evsel->attr.sample_type;
1072
1073         return evlist->combined_sample_type;
1074 }
1075
1076 u64 perf_evlist__combined_sample_type(struct perf_evlist *evlist)
1077 {
1078         evlist->combined_sample_type = 0;
1079         return __perf_evlist__combined_sample_type(evlist);
1080 }
1081
1082 bool perf_evlist__valid_read_format(struct perf_evlist *evlist)
1083 {
1084         struct perf_evsel *first = perf_evlist__first(evlist), *pos = first;
1085         u64 read_format = first->attr.read_format;
1086         u64 sample_type = first->attr.sample_type;
1087
1088         evlist__for_each(evlist, pos) {
1089                 if (read_format != pos->attr.read_format)
1090                         return false;
1091         }
1092
1093         /* PERF_SAMPLE_READ imples PERF_FORMAT_ID. */
1094         if ((sample_type & PERF_SAMPLE_READ) &&
1095             !(read_format & PERF_FORMAT_ID)) {
1096                 return false;
1097         }
1098
1099         return true;
1100 }
1101
1102 u64 perf_evlist__read_format(struct perf_evlist *evlist)
1103 {
1104         struct perf_evsel *first = perf_evlist__first(evlist);
1105         return first->attr.read_format;
1106 }
1107
1108 u16 perf_evlist__id_hdr_size(struct perf_evlist *evlist)
1109 {
1110         struct perf_evsel *first = perf_evlist__first(evlist);
1111         struct perf_sample *data;
1112         u64 sample_type;
1113         u16 size = 0;
1114
1115         if (!first->attr.sample_id_all)
1116                 goto out;
1117
1118         sample_type = first->attr.sample_type;
1119
1120         if (sample_type & PERF_SAMPLE_TID)
1121                 size += sizeof(data->tid) * 2;
1122
1123        if (sample_type & PERF_SAMPLE_TIME)
1124                 size += sizeof(data->time);
1125
1126         if (sample_type & PERF_SAMPLE_ID)
1127                 size += sizeof(data->id);
1128
1129         if (sample_type & PERF_SAMPLE_STREAM_ID)
1130                 size += sizeof(data->stream_id);
1131
1132         if (sample_type & PERF_SAMPLE_CPU)
1133                 size += sizeof(data->cpu) * 2;
1134
1135         if (sample_type & PERF_SAMPLE_IDENTIFIER)
1136                 size += sizeof(data->id);
1137 out:
1138         return size;
1139 }
1140
1141 bool perf_evlist__valid_sample_id_all(struct perf_evlist *evlist)
1142 {
1143         struct perf_evsel *first = perf_evlist__first(evlist), *pos = first;
1144
1145         evlist__for_each_continue(evlist, pos) {
1146                 if (first->attr.sample_id_all != pos->attr.sample_id_all)
1147                         return false;
1148         }
1149
1150         return true;
1151 }
1152
1153 bool perf_evlist__sample_id_all(struct perf_evlist *evlist)
1154 {
1155         struct perf_evsel *first = perf_evlist__first(evlist);
1156         return first->attr.sample_id_all;
1157 }
1158
1159 void perf_evlist__set_selected(struct perf_evlist *evlist,
1160                                struct perf_evsel *evsel)
1161 {
1162         evlist->selected = evsel;
1163 }
1164
1165 void perf_evlist__close(struct perf_evlist *evlist)
1166 {
1167         struct perf_evsel *evsel;
1168         int ncpus = cpu_map__nr(evlist->cpus);
1169         int nthreads = thread_map__nr(evlist->threads);
1170         int n;
1171
1172         evlist__for_each_reverse(evlist, evsel) {
1173                 n = evsel->cpus ? evsel->cpus->nr : ncpus;
1174                 perf_evsel__close(evsel, n, nthreads);
1175         }
1176 }
1177
1178 int perf_evlist__open(struct perf_evlist *evlist)
1179 {
1180         struct perf_evsel *evsel;
1181         int err;
1182
1183         perf_evlist__update_id_pos(evlist);
1184
1185         evlist__for_each(evlist, evsel) {
1186                 err = perf_evsel__open(evsel, evlist->cpus, evlist->threads);
1187                 if (err < 0)
1188                         goto out_err;
1189         }
1190
1191         return 0;
1192 out_err:
1193         perf_evlist__close(evlist);
1194         errno = -err;
1195         return err;
1196 }
1197
1198 int perf_evlist__prepare_workload(struct perf_evlist *evlist, struct target *target,
1199                                   const char *argv[], bool pipe_output,
1200                                   void (*exec_error)(int signo, siginfo_t *info, void *ucontext))
1201 {
1202         int child_ready_pipe[2], go_pipe[2];
1203         char bf;
1204
1205         if (pipe(child_ready_pipe) < 0) {
1206                 perror("failed to create 'ready' pipe");
1207                 return -1;
1208         }
1209
1210         if (pipe(go_pipe) < 0) {
1211                 perror("failed to create 'go' pipe");
1212                 goto out_close_ready_pipe;
1213         }
1214
1215         evlist->workload.pid = fork();
1216         if (evlist->workload.pid < 0) {
1217                 perror("failed to fork");
1218                 goto out_close_pipes;
1219         }
1220
1221         if (!evlist->workload.pid) {
1222                 int ret;
1223
1224                 if (pipe_output)
1225                         dup2(2, 1);
1226
1227                 signal(SIGTERM, SIG_DFL);
1228
1229                 close(child_ready_pipe[0]);
1230                 close(go_pipe[1]);
1231                 fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
1232
1233                 /*
1234                  * Tell the parent we're ready to go
1235                  */
1236                 close(child_ready_pipe[1]);
1237
1238                 /*
1239                  * Wait until the parent tells us to go.
1240                  */
1241                 ret = read(go_pipe[0], &bf, 1);
1242                 /*
1243                  * The parent will ask for the execvp() to be performed by
1244                  * writing exactly one byte, in workload.cork_fd, usually via
1245                  * perf_evlist__start_workload().
1246                  *
1247                  * For cancelling the workload without actuallin running it,
1248                  * the parent will just close workload.cork_fd, without writing
1249                  * anything, i.e. read will return zero and we just exit()
1250                  * here.
1251                  */
1252                 if (ret != 1) {
1253                         if (ret == -1)
1254                                 perror("unable to read pipe");
1255                         exit(ret);
1256                 }
1257
1258                 execvp(argv[0], (char **)argv);
1259
1260                 if (exec_error) {
1261                         union sigval val;
1262
1263                         val.sival_int = errno;
1264                         if (sigqueue(getppid(), SIGUSR1, val))
1265                                 perror(argv[0]);
1266                 } else
1267                         perror(argv[0]);
1268                 exit(-1);
1269         }
1270
1271         if (exec_error) {
1272                 struct sigaction act = {
1273                         .sa_flags     = SA_SIGINFO,
1274                         .sa_sigaction = exec_error,
1275                 };
1276                 sigaction(SIGUSR1, &act, NULL);
1277         }
1278
1279         if (target__none(target))
1280                 evlist->threads->map[0] = evlist->workload.pid;
1281
1282         close(child_ready_pipe[1]);
1283         close(go_pipe[0]);
1284         /*
1285          * wait for child to settle
1286          */
1287         if (read(child_ready_pipe[0], &bf, 1) == -1) {
1288                 perror("unable to read pipe");
1289                 goto out_close_pipes;
1290         }
1291
1292         fcntl(go_pipe[1], F_SETFD, FD_CLOEXEC);
1293         evlist->workload.cork_fd = go_pipe[1];
1294         close(child_ready_pipe[0]);
1295         return 0;
1296
1297 out_close_pipes:
1298         close(go_pipe[0]);
1299         close(go_pipe[1]);
1300 out_close_ready_pipe:
1301         close(child_ready_pipe[0]);
1302         close(child_ready_pipe[1]);
1303         return -1;
1304 }
1305
1306 int perf_evlist__start_workload(struct perf_evlist *evlist)
1307 {
1308         if (evlist->workload.cork_fd > 0) {
1309                 char bf = 0;
1310                 int ret;
1311                 /*
1312                  * Remove the cork, let it rip!
1313                  */
1314                 ret = write(evlist->workload.cork_fd, &bf, 1);
1315                 if (ret < 0)
1316                         perror("enable to write to pipe");
1317
1318                 close(evlist->workload.cork_fd);
1319                 return ret;
1320         }
1321
1322         return 0;
1323 }
1324
1325 int perf_evlist__parse_sample(struct perf_evlist *evlist, union perf_event *event,
1326                               struct perf_sample *sample)
1327 {
1328         struct perf_evsel *evsel = perf_evlist__event2evsel(evlist, event);
1329
1330         if (!evsel)
1331                 return -EFAULT;
1332         return perf_evsel__parse_sample(evsel, event, sample);
1333 }
1334
1335 size_t perf_evlist__fprintf(struct perf_evlist *evlist, FILE *fp)
1336 {
1337         struct perf_evsel *evsel;
1338         size_t printed = 0;
1339
1340         evlist__for_each(evlist, evsel) {
1341                 printed += fprintf(fp, "%s%s", evsel->idx ? ", " : "",
1342                                    perf_evsel__name(evsel));
1343         }
1344
1345         return printed + fprintf(fp, "\n");
1346 }
1347
1348 int perf_evlist__strerror_tp(struct perf_evlist *evlist __maybe_unused,
1349                              int err, char *buf, size_t size)
1350 {
1351         char sbuf[128];
1352
1353         switch (err) {
1354         case ENOENT:
1355                 scnprintf(buf, size, "%s",
1356                           "Error:\tUnable to find debugfs\n"
1357                           "Hint:\tWas your kernel was compiled with debugfs support?\n"
1358                           "Hint:\tIs the debugfs filesystem mounted?\n"
1359                           "Hint:\tTry 'sudo mount -t debugfs nodev /sys/kernel/debug'");
1360                 break;
1361         case EACCES:
1362                 scnprintf(buf, size,
1363                           "Error:\tNo permissions to read %s/tracing/events/raw_syscalls\n"
1364                           "Hint:\tTry 'sudo mount -o remount,mode=755 %s'\n",
1365                           debugfs_mountpoint, debugfs_mountpoint);
1366                 break;
1367         default:
1368                 scnprintf(buf, size, "%s", strerror_r(err, sbuf, sizeof(sbuf)));
1369                 break;
1370         }
1371
1372         return 0;
1373 }
1374
1375 int perf_evlist__strerror_open(struct perf_evlist *evlist __maybe_unused,
1376                                int err, char *buf, size_t size)
1377 {
1378         int printed, value;
1379         char sbuf[STRERR_BUFSIZE], *emsg = strerror_r(err, sbuf, sizeof(sbuf));
1380
1381         switch (err) {
1382         case EACCES:
1383         case EPERM:
1384                 printed = scnprintf(buf, size,
1385                                     "Error:\t%s.\n"
1386                                     "Hint:\tCheck /proc/sys/kernel/perf_event_paranoid setting.", emsg);
1387
1388                 value = perf_event_paranoid();
1389
1390                 printed += scnprintf(buf + printed, size - printed, "\nHint:\t");
1391
1392                 if (value >= 2) {
1393                         printed += scnprintf(buf + printed, size - printed,
1394                                              "For your workloads it needs to be <= 1\nHint:\t");
1395                 }
1396                 printed += scnprintf(buf + printed, size - printed,
1397                                      "For system wide tracing it needs to be set to -1.\n");
1398
1399                 printed += scnprintf(buf + printed, size - printed,
1400                                     "Hint:\tTry: 'sudo sh -c \"echo -1 > /proc/sys/kernel/perf_event_paranoid\"'\n"
1401                                     "Hint:\tThe current value is %d.", value);
1402                 break;
1403         default:
1404                 scnprintf(buf, size, "%s", emsg);
1405                 break;
1406         }
1407
1408         return 0;
1409 }
1410
1411 void perf_evlist__to_front(struct perf_evlist *evlist,
1412                            struct perf_evsel *move_evsel)
1413 {
1414         struct perf_evsel *evsel, *n;
1415         LIST_HEAD(move);
1416
1417         if (move_evsel == perf_evlist__first(evlist))
1418                 return;
1419
1420         evlist__for_each_safe(evlist, n, evsel) {
1421                 if (evsel->leader == move_evsel->leader)
1422                         list_move_tail(&evsel->node, &move);
1423         }
1424
1425         list_splice(&move, &evlist->entries);
1426 }
1427
1428 void perf_evlist__set_tracking_event(struct perf_evlist *evlist,
1429                                      struct perf_evsel *tracking_evsel)
1430 {
1431         struct perf_evsel *evsel;
1432
1433         if (tracking_evsel->tracking)
1434                 return;
1435
1436         evlist__for_each(evlist, evsel) {
1437                 if (evsel != tracking_evsel)
1438                         evsel->tracking = false;
1439         }
1440
1441         tracking_evsel->tracking = true;
1442 }