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 "debugfs.h"
  11 #include <poll.h>
  12 #include "cpumap.h"
  13 #include "thread_map.h"
  14 #include "evlist.h"
  15 #include "evsel.h"
  16 #include <unistd.h>
  17
  18 #include "parse-events.h"
  19
  20 #include <sys/mman.h>
  21
  22 #include <linux/bitops.h>
  23 #include <linux/hash.h>
  24
  25 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))
  26 #define SID(e, x, y) xyarray__entry(e->sample_id, x, y)
  27
  28 void perf_evlist__init(struct perf_evlist *evlist, struct cpu_map *cpus,
  29                        struct thread_map *threads)
  30 {
  31         int i;
  32
  33         for (i = 0; i < PERF_EVLIST__HLIST_SIZE; ++i)
  34                 INIT_HLIST_HEAD(&evlist->heads[i]);
  35         INIT_LIST_HEAD(&evlist->entries);
  36         perf_evlist__set_maps(evlist, cpus, threads);
  37         evlist->workload.pid = -1;
  38 }
  39
  40 struct perf_evlist *perf_evlist__new(struct cpu_map *cpus,
  41                                      struct thread_map *threads)
  42 {
  43         struct perf_evlist *evlist = zalloc(sizeof(*evlist));
  44
  45         if (evlist != NULL)
  46                 perf_evlist__init(evlist, cpus, threads);
  47
  48         return evlist;
  49 }
  50
  51 void perf_evlist__config_attrs(struct perf_evlist *evlist,
  52                                struct perf_record_opts *opts)
  53 {
  54         struct perf_evsel *evsel, *first;
  55
  56         if (evlist->cpus->map[0] < 0)
  57                 opts->no_inherit = true;
  58
  59         first = list_entry(evlist->entries.next, struct perf_evsel, node);
  60
  61         list_for_each_entry(evsel, &evlist->entries, node) {
  62                 perf_evsel__config(evsel, opts, first);
  63
  64                 if (evlist->nr_entries > 1)
  65                         evsel->attr.sample_type |= PERF_SAMPLE_ID;
  66         }
  67 }
  68
  69 static void perf_evlist__purge(struct perf_evlist *evlist)
  70 {
  71         struct perf_evsel *pos, *n;
  72
  73         list_for_each_entry_safe(pos, n, &evlist->entries, node) {
  74                 list_del_init(&pos->node);
  75                 perf_evsel__delete(pos);
  76         }
  77
  78         evlist->nr_entries = 0;
  79 }
  80
  81 void perf_evlist__exit(struct perf_evlist *evlist)
  82 {
  83         free(evlist->mmap);
  84         free(evlist->pollfd);
  85         evlist->mmap = NULL;
  86         evlist->pollfd = NULL;
  87 }
  88
  89 void perf_evlist__delete(struct perf_evlist *evlist)
  90 {
  91         perf_evlist__purge(evlist);
  92         perf_evlist__exit(evlist);
  93         free(evlist);
  94 }
  95
  96 void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry)
  97 {
  98         list_add_tail(&entry->node, &evlist->entries);
  99         ++evlist->nr_entries;
 100 }
 101
 102 void perf_evlist__splice_list_tail(struct perf_evlist *evlist,
 103                                    struct list_head *list,
 104                                    int nr_entries)
 105 {
 106         list_splice_tail(list, &evlist->entries);
 107         evlist->nr_entries += nr_entries;
 108 }
 109
 110 int perf_evlist__add_default(struct perf_evlist *evlist)
 111 {
 112         struct perf_event_attr attr = {
 113                 .type = PERF_TYPE_HARDWARE,
 114                 .config = PERF_COUNT_HW_CPU_CYCLES,
 115         };
 116         struct perf_evsel *evsel;
 117
 118         event_attr_init(&attr);
 119
 120         evsel = perf_evsel__new(&attr, 0);
 121         if (evsel == NULL)
 122                 goto error;
 123
 124         /* use strdup() because free(evsel) assumes name is allocated */
 125         evsel->name = strdup("cycles");
 126         if (!evsel->name)
 127                 goto error_free;
 128
 129         perf_evlist__add(evlist, evsel);
 130         return 0;
 131 error_free:
 132         perf_evsel__delete(evsel);
 133 error:
 134         return -ENOMEM;
 135 }
 136
 137 int perf_evlist__add_attrs(struct perf_evlist *evlist,
 138                            struct perf_event_attr *attrs, size_t nr_attrs)
 139 {
 140         struct perf_evsel *evsel, *n;
 141         LIST_HEAD(head);
 142         size_t i;
 143
 144         for (i = 0; i < nr_attrs; i++) {
 145                 evsel = perf_evsel__new(attrs + i, evlist->nr_entries + i);
 146                 if (evsel == NULL)
 147                         goto out_delete_partial_list;
 148                 list_add_tail(&evsel->node, &head);
 149         }
 150
 151         perf_evlist__splice_list_tail(evlist, &head, nr_attrs);
 152
 153         return 0;
 154
 155 out_delete_partial_list:
 156         list_for_each_entry_safe(evsel, n, &head, node)
 157                 perf_evsel__delete(evsel);
 158         return -1;
 159 }
 160
 161 static int trace_event__id(const char *evname)
 162 {
 163         char *filename, *colon;
 164         int err = -1, fd;
 165
 166         if (asprintf(&filename, "%s/%s/id", tracing_events_path, evname) < 0)
 167                 return -1;
 168
 169         colon = strrchr(filename, ':');
 170         if (colon != NULL)
 171                 *colon = '/';
 172
 173         fd = open(filename, O_RDONLY);
 174         if (fd >= 0) {
 175                 char id[16];
 176                 if (read(fd, id, sizeof(id)) > 0)
 177                         err = atoi(id);
 178                 close(fd);
 179         }
 180
 181         free(filename);
 182         return err;
 183 }
 184
 185 int perf_evlist__add_tracepoints(struct perf_evlist *evlist,
 186                                  const char *tracepoints[],
 187                                  size_t nr_tracepoints)
 188 {
 189         int err;
 190         size_t i;
 191         struct perf_event_attr *attrs = zalloc(nr_tracepoints * sizeof(*attrs));
 192
 193         if (attrs == NULL)
 194                 return -1;
 195
 196         for (i = 0; i < nr_tracepoints; i++) {
 197                 err = trace_event__id(tracepoints[i]);
 198
 199                 if (err < 0)
 200                         goto out_free_attrs;
 201
 202                 attrs[i].type          = PERF_TYPE_TRACEPOINT;
 203                 attrs[i].config        = err;
 204                 attrs[i].sample_type   = (PERF_SAMPLE_RAW | PERF_SAMPLE_TIME |
 205                                           PERF_SAMPLE_CPU);
 206                 attrs[i].sample_period = 1;
 207         }
 208
 209         err = perf_evlist__add_attrs(evlist, attrs, nr_tracepoints);
 210 out_free_attrs:
 211         free(attrs);
 212         return err;
 213 }
 214
 215 static struct perf_evsel *
 216         perf_evlist__find_tracepoint_by_id(struct perf_evlist *evlist, int id)
 217 {
 218         struct perf_evsel *evsel;
 219
 220         list_for_each_entry(evsel, &evlist->entries, node) {
 221                 if (evsel->attr.type   == PERF_TYPE_TRACEPOINT &&
 222                     (int)evsel->attr.config == id)
 223                         return evsel;
 224         }
 225
 226         return NULL;
 227 }
 228
 229 int perf_evlist__set_tracepoints_handlers(struct perf_evlist *evlist,
 230                                           const struct perf_evsel_str_handler *assocs,
 231                                           size_t nr_assocs)
 232 {
 233         struct perf_evsel *evsel;
 234         int err;
 235         size_t i;
 236
 237         for (i = 0; i < nr_assocs; i++) {
 238                 err = trace_event__id(assocs[i].name);
 239                 if (err < 0)
 240                         goto out;
 241
 242                 evsel = perf_evlist__find_tracepoint_by_id(evlist, err);
 243                 if (evsel == NULL)
 244                         continue;
 245
 246                 err = -EEXIST;
 247                 if (evsel->handler.func != NULL)
 248                         goto out;
 249                 evsel->handler.func = assocs[i].handler;
 250         }
 251
 252         err = 0;
 253 out:
 254         return err;
 255 }
 256
 257 void perf_evlist__disable(struct perf_evlist *evlist)
 258 {
 259         int cpu, thread;
 260         struct perf_evsel *pos;
 261
 262         for (cpu = 0; cpu < evlist->cpus->nr; cpu++) {
 263                 list_for_each_entry(pos, &evlist->entries, node) {
 264                         for (thread = 0; thread < evlist->threads->nr; thread++)
 265                                 ioctl(FD(pos, cpu, thread), PERF_EVENT_IOC_DISABLE);
 266                 }
 267         }
 268 }
 269
 270 void perf_evlist__enable(struct perf_evlist *evlist)
 271 {
 272         int cpu, thread;
 273         struct perf_evsel *pos;
 274
 275         for (cpu = 0; cpu < evlist->cpus->nr; cpu++) {
 276                 list_for_each_entry(pos, &evlist->entries, node) {
 277                         for (thread = 0; thread < evlist->threads->nr; thread++)
 278                                 ioctl(FD(pos, cpu, thread), PERF_EVENT_IOC_ENABLE);
 279                 }
 280         }
 281 }
 282
 283 static int perf_evlist__alloc_pollfd(struct perf_evlist *evlist)
 284 {
 285         int nfds = evlist->cpus->nr * evlist->threads->nr * evlist->nr_entries;
 286         evlist->pollfd = malloc(sizeof(struct pollfd) * nfds);
 287         return evlist->pollfd != NULL ? 0 : -ENOMEM;
 288 }
 289
 290 void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd)
 291 {
 292         fcntl(fd, F_SETFL, O_NONBLOCK);
 293         evlist->pollfd[evlist->nr_fds].fd = fd;
 294         evlist->pollfd[evlist->nr_fds].events = POLLIN;
 295         evlist->nr_fds++;
 296 }
 297
 298 static void perf_evlist__id_hash(struct perf_evlist *evlist,
 299                                  struct perf_evsel *evsel,
 300                                  int cpu, int thread, u64 id)
 301 {
 302         int hash;
 303         struct perf_sample_id *sid = SID(evsel, cpu, thread);
 304
 305         sid->id = id;
 306         sid->evsel = evsel;
 307         hash = hash_64(sid->id, PERF_EVLIST__HLIST_BITS);
 308         hlist_add_head(&sid->node, &evlist->heads[hash]);
 309 }
 310
 311 void perf_evlist__id_add(struct perf_evlist *evlist, struct perf_evsel *evsel,
 312                          int cpu, int thread, u64 id)
 313 {
 314         perf_evlist__id_hash(evlist, evsel, cpu, thread, id);
 315         evsel->id[evsel->ids++] = id;
 316 }
 317
 318 static int perf_evlist__id_add_fd(struct perf_evlist *evlist,
 319                                   struct perf_evsel *evsel,
 320                                   int cpu, int thread, int fd)
 321 {
 322         u64 read_data[4] = { 0, };
 323         int id_idx = 1; /* The first entry is the counter value */
 324
 325         if (!(evsel->attr.read_format & PERF_FORMAT_ID) ||
 326             read(fd, &read_data, sizeof(read_data)) == -1)
 327                 return -1;
 328
 329         if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
 330                 ++id_idx;
 331         if (evsel->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
 332                 ++id_idx;
 333
 334         perf_evlist__id_add(evlist, evsel, cpu, thread, read_data[id_idx]);
 335         return 0;
 336 }
 337
 338 struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id)
 339 {
 340         struct hlist_head *head;
 341         struct hlist_node *pos;
 342         struct perf_sample_id *sid;
 343         int hash;
 344
 345         if (evlist->nr_entries == 1)
 346                 return list_entry(evlist->entries.next, struct perf_evsel, node);
 347
 348         hash = hash_64(id, PERF_EVLIST__HLIST_BITS);
 349         head = &evlist->heads[hash];
 350
 351         hlist_for_each_entry(sid, pos, head, node)
 352                 if (sid->id == id)
 353                         return sid->evsel;
 354
 355         if (!perf_evlist__sample_id_all(evlist))
 356                 return list_entry(evlist->entries.next, struct perf_evsel, node);
 357
 358         return NULL;
 359 }
 360
 361 union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx)
 362 {
 363         /* XXX Move this to perf.c, making it generally available */
 364         unsigned int page_size = sysconf(_SC_PAGE_SIZE);
 365         struct perf_mmap *md = &evlist->mmap[idx];
 366         unsigned int head = perf_mmap__read_head(md);
 367         unsigned int old = md->prev;
 368         unsigned char *data = md->base + page_size;
 369         union perf_event *event = NULL;
 370
 371         if (evlist->overwrite) {
 372                 /*
 373                  * If we're further behind than half the buffer, there's a chance
 374                  * the writer will bite our tail and mess up the samples under us.
 375                  *
 376                  * If we somehow ended up ahead of the head, we got messed up.
 377                  *
 378                  * In either case, truncate and restart at head.
 379                  */
 380                 int diff = head - old;
 381                 if (diff > md->mask / 2 || diff < 0) {
 382                         fprintf(stderr, "WARNING: failed to keep up with mmap data.\n");
 383
 384                         /*
 385                          * head points to a known good entry, start there.
 386                          */
 387                         old = head;
 388                 }
 389         }
 390
 391         if (old != head) {
 392                 size_t size;
 393
 394                 event = (union perf_event *)&data[old & md->mask];
 395                 size = event->header.size;
 396
 397                 /*
 398                  * Event straddles the mmap boundary -- header should always
 399                  * be inside due to u64 alignment of output.
 400                  */
 401                 if ((old & md->mask) + size != ((old + size) & md->mask)) {
 402                         unsigned int offset = old;
 403                         unsigned int len = min(sizeof(*event), size), cpy;
 404                         void *dst = &evlist->event_copy;
 405
 406                         do {
 407                                 cpy = min(md->mask + 1 - (offset & md->mask), len);
 408                                 memcpy(dst, &data[offset & md->mask], cpy);
 409                                 offset += cpy;
 410                                 dst += cpy;
 411                                 len -= cpy;
 412                         } while (len);
 413
 414                         event = &evlist->event_copy;
 415                 }
 416
 417                 old += size;
 418         }
 419
 420         md->prev = old;
 421
 422         if (!evlist->overwrite)
 423                 perf_mmap__write_tail(md, old);
 424
 425         return event;
 426 }
 427
 428 void perf_evlist__munmap(struct perf_evlist *evlist)
 429 {
 430         int i;
 431
 432         for (i = 0; i < evlist->nr_mmaps; i++) {
 433                 if (evlist->mmap[i].base != NULL) {
 434                         munmap(evlist->mmap[i].base, evlist->mmap_len);
 435                         evlist->mmap[i].base = NULL;
 436                 }
 437         }
 438
 439         free(evlist->mmap);
 440         evlist->mmap = NULL;
 441 }
 442
 443 static int perf_evlist__alloc_mmap(struct perf_evlist *evlist)
 444 {
 445         evlist->nr_mmaps = evlist->cpus->nr;
 446         if (evlist->cpus->map[0] == -1)
 447                 evlist->nr_mmaps = evlist->threads->nr;
 448         evlist->mmap = zalloc(evlist->nr_mmaps * sizeof(struct perf_mmap));
 449         return evlist->mmap != NULL ? 0 : -ENOMEM;
 450 }
 451
 452 static int __perf_evlist__mmap(struct perf_evlist *evlist,
 453                                int idx, int prot, int mask, int fd)
 454 {
 455         evlist->mmap[idx].prev = 0;
 456         evlist->mmap[idx].mask = mask;
 457         evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, prot,
 458                                       MAP_SHARED, fd, 0);
 459         if (evlist->mmap[idx].base == MAP_FAILED) {
 460                 evlist->mmap[idx].base = NULL;
 461                 return -1;
 462         }
 463
 464         perf_evlist__add_pollfd(evlist, fd);
 465         return 0;
 466 }
 467
 468 static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist, int prot, int mask)
 469 {
 470         struct perf_evsel *evsel;
 471         int cpu, thread;
 472
 473         for (cpu = 0; cpu < evlist->cpus->nr; cpu++) {
 474                 int output = -1;
 475
 476                 for (thread = 0; thread < evlist->threads->nr; thread++) {
 477                         list_for_each_entry(evsel, &evlist->entries, node) {
 478                                 int fd = FD(evsel, cpu, thread);
 479
 480                                 if (output == -1) {
 481                                         output = fd;
 482                                         if (__perf_evlist__mmap(evlist, cpu,
 483                                                                 prot, mask, output) < 0)
 484                                                 goto out_unmap;
 485                                 } else {
 486                                         if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, output) != 0)
 487                                                 goto out_unmap;
 488                                 }
 489
 490                                 if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
 491                                     perf_evlist__id_add_fd(evlist, evsel, cpu, thread, fd) < 0)
 492                                         goto out_unmap;
 493                         }
 494                 }
 495         }
 496
 497         return 0;
 498
 499 out_unmap:
 500         for (cpu = 0; cpu < evlist->cpus->nr; cpu++) {
 501                 if (evlist->mmap[cpu].base != NULL) {
 502                         munmap(evlist->mmap[cpu].base, evlist->mmap_len);
 503                         evlist->mmap[cpu].base = NULL;
 504                 }
 505         }
 506         return -1;
 507 }
 508
 509 static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist, int prot, int mask)
 510 {
 511         struct perf_evsel *evsel;
 512         int thread;
 513
 514         for (thread = 0; thread < evlist->threads->nr; thread++) {
 515                 int output = -1;
 516
 517                 list_for_each_entry(evsel, &evlist->entries, node) {
 518                         int fd = FD(evsel, 0, thread);
 519
 520                         if (output == -1) {
 521                                 output = fd;
 522                                 if (__perf_evlist__mmap(evlist, thread,
 523                                                         prot, mask, output) < 0)
 524                                         goto out_unmap;
 525                         } else {
 526                                 if (ioctl(fd, PERF_EVENT_IOC_SET_OUTPUT, output) != 0)
 527                                         goto out_unmap;
 528                         }
 529
 530                         if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
 531                             perf_evlist__id_add_fd(evlist, evsel, 0, thread, fd) < 0)
 532                                 goto out_unmap;
 533                 }
 534         }
 535
 536         return 0;
 537
 538 out_unmap:
 539         for (thread = 0; thread < evlist->threads->nr; thread++) {
 540                 if (evlist->mmap[thread].base != NULL) {
 541                         munmap(evlist->mmap[thread].base, evlist->mmap_len);
 542                         evlist->mmap[thread].base = NULL;
 543                 }
 544         }
 545         return -1;
 546 }
 547
 548 /** perf_evlist__mmap - Create per cpu maps to receive events
 549  *
 550  * @evlist - list of events
 551  * @pages - map length in pages
 552  * @overwrite - overwrite older events?
 553  *
 554  * If overwrite is false the user needs to signal event consuption using:
 555  *
 556  *      struct perf_mmap *m = &evlist->mmap[cpu];
 557  *      unsigned int head = perf_mmap__read_head(m);
 558  *
 559  *      perf_mmap__write_tail(m, head)
 560  *
 561  * Using perf_evlist__read_on_cpu does this automatically.
 562  */
 563 int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
 564                       bool overwrite)
 565 {
 566         unsigned int page_size = sysconf(_SC_PAGE_SIZE);
 567         struct perf_evsel *evsel;
 568         const struct cpu_map *cpus = evlist->cpus;
 569         const struct thread_map *threads = evlist->threads;
 570         int prot = PROT_READ | (overwrite ? 0 : PROT_WRITE), mask;
 571
 572         /* 512 kiB: default amount of unprivileged mlocked memory */
 573         if (pages == UINT_MAX)
 574                 pages = (512 * 1024) / page_size;
 575         else if (!is_power_of_2(pages))
 576                 return -EINVAL;
 577
 578         mask = pages * page_size - 1;
 579
 580         if (evlist->mmap == NULL && perf_evlist__alloc_mmap(evlist) < 0)
 581                 return -ENOMEM;
 582
 583         if (evlist->pollfd == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
 584                 return -ENOMEM;
 585
 586         evlist->overwrite = overwrite;
 587         evlist->mmap_len = (pages + 1) * page_size;
 588
 589         list_for_each_entry(evsel, &evlist->entries, node) {
 590                 if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
 591                     evsel->sample_id == NULL &&
 592                     perf_evsel__alloc_id(evsel, cpus->nr, threads->nr) < 0)
 593                         return -ENOMEM;
 594         }
 595
 596         if (evlist->cpus->map[0] == -1)
 597                 return perf_evlist__mmap_per_thread(evlist, prot, mask);
 598
 599         return perf_evlist__mmap_per_cpu(evlist, prot, mask);
 600 }
 601
 602 int perf_evlist__create_maps(struct perf_evlist *evlist, const char *target_pid,
 603                              const char *target_tid, uid_t uid, const char *cpu_list)
 604 {
 605         evlist->threads = thread_map__new_str(target_pid, target_tid, uid);
 606
 607         if (evlist->threads == NULL)
 608                 return -1;
 609
 610         if (uid != UINT_MAX || (cpu_list == NULL && target_tid))
 611                 evlist->cpus = cpu_map__dummy_new();
 612         else
 613                 evlist->cpus = cpu_map__new(cpu_list);
 614
 615         if (evlist->cpus == NULL)
 616                 goto out_delete_threads;
 617
 618         return 0;
 619
 620 out_delete_threads:
 621         thread_map__delete(evlist->threads);
 622         return -1;
 623 }
 624
 625 void perf_evlist__delete_maps(struct perf_evlist *evlist)
 626 {
 627         cpu_map__delete(evlist->cpus);
 628         thread_map__delete(evlist->threads);
 629         evlist->cpus    = NULL;
 630         evlist->threads = NULL;
 631 }
 632
 633 int perf_evlist__set_filters(struct perf_evlist *evlist)
 634 {
 635         const struct thread_map *threads = evlist->threads;
 636         const struct cpu_map *cpus = evlist->cpus;
 637         struct perf_evsel *evsel;
 638         char *filter;
 639         int thread;
 640         int cpu;
 641         int err;
 642         int fd;
 643
 644         list_for_each_entry(evsel, &evlist->entries, node) {
 645                 filter = evsel->filter;
 646                 if (!filter)
 647                         continue;
 648                 for (cpu = 0; cpu < cpus->nr; cpu++) {
 649                         for (thread = 0; thread < threads->nr; thread++) {
 650                                 fd = FD(evsel, cpu, thread);
 651                                 err = ioctl(fd, PERF_EVENT_IOC_SET_FILTER, filter);
 652                                 if (err)
 653                                         return err;
 654                         }
 655                 }
 656         }
 657
 658         return 0;
 659 }
 660
 661 bool perf_evlist__valid_sample_type(const struct perf_evlist *evlist)
 662 {
 663         struct perf_evsel *pos, *first;
 664
 665         pos = first = list_entry(evlist->entries.next, struct perf_evsel, node);
 666
 667         list_for_each_entry_continue(pos, &evlist->entries, node) {
 668                 if (first->attr.sample_type != pos->attr.sample_type)
 669                         return false;
 670         }
 671
 672         return true;
 673 }
 674
 675 u64 perf_evlist__sample_type(const struct perf_evlist *evlist)
 676 {
 677         struct perf_evsel *first;
 678
 679         first = list_entry(evlist->entries.next, struct perf_evsel, node);
 680         return first->attr.sample_type;
 681 }
 682
 683 u16 perf_evlist__id_hdr_size(const struct perf_evlist *evlist)
 684 {
 685         struct perf_evsel *first;
 686         struct perf_sample *data;
 687         u64 sample_type;
 688         u16 size = 0;
 689
 690         first = list_entry(evlist->entries.next, struct perf_evsel, node);
 691
 692         if (!first->attr.sample_id_all)
 693                 goto out;
 694
 695         sample_type = first->attr.sample_type;
 696
 697         if (sample_type & PERF_SAMPLE_TID)
 698                 size += sizeof(data->tid) * 2;
 699
 700        if (sample_type & PERF_SAMPLE_TIME)
 701                 size += sizeof(data->time);
 702
 703         if (sample_type & PERF_SAMPLE_ID)
 704                 size += sizeof(data->id);
 705
 706         if (sample_type & PERF_SAMPLE_STREAM_ID)
 707                 size += sizeof(data->stream_id);
 708
 709         if (sample_type & PERF_SAMPLE_CPU)
 710                 size += sizeof(data->cpu) * 2;
 711 out:
 712         return size;
 713 }
 714
 715 bool perf_evlist__valid_sample_id_all(const struct perf_evlist *evlist)
 716 {
 717         struct perf_evsel *pos, *first;
 718
 719         pos = first = list_entry(evlist->entries.next, struct perf_evsel, node);
 720
 721         list_for_each_entry_continue(pos, &evlist->entries, node) {
 722                 if (first->attr.sample_id_all != pos->attr.sample_id_all)
 723                         return false;
 724         }
 725
 726         return true;
 727 }
 728
 729 bool perf_evlist__sample_id_all(const struct perf_evlist *evlist)
 730 {
 731         struct perf_evsel *first;
 732
 733         first = list_entry(evlist->entries.next, struct perf_evsel, node);
 734         return first->attr.sample_id_all;
 735 }
 736
 737 void perf_evlist__set_selected(struct perf_evlist *evlist,
 738                                struct perf_evsel *evsel)
 739 {
 740         evlist->selected = evsel;
 741 }
 742
 743 int perf_evlist__open(struct perf_evlist *evlist, bool group)
 744 {
 745         struct perf_evsel *evsel, *first;
 746         int err, ncpus, nthreads;
 747
 748         first = list_entry(evlist->entries.next, struct perf_evsel, node);
 749
 750         list_for_each_entry(evsel, &evlist->entries, node) {
 751                 struct xyarray *group_fd = NULL;
 752
 753                 if (group && evsel != first)
 754                         group_fd = first->fd;
 755
 756                 err = perf_evsel__open(evsel, evlist->cpus, evlist->threads,
 757                                        group, group_fd);
 758                 if (err < 0)
 759                         goto out_err;
 760         }
 761
 762         return 0;
 763 out_err:
 764         ncpus = evlist->cpus ? evlist->cpus->nr : 1;
 765         nthreads = evlist->threads ? evlist->threads->nr : 1;
 766
 767         list_for_each_entry_reverse(evsel, &evlist->entries, node)
 768                 perf_evsel__close(evsel, ncpus, nthreads);
 769
 770         errno = -err;
 771         return err;
 772 }
 773
 774 int perf_evlist__prepare_workload(struct perf_evlist *evlist,
 775                                   struct perf_record_opts *opts,
 776                                   const char *argv[])
 777 {
 778         int child_ready_pipe[2], go_pipe[2];
 779         char bf;
 780
 781         if (pipe(child_ready_pipe) < 0) {
 782                 perror("failed to create 'ready' pipe");
 783                 return -1;
 784         }
 785
 786         if (pipe(go_pipe) < 0) {
 787                 perror("failed to create 'go' pipe");
 788                 goto out_close_ready_pipe;
 789         }
 790
 791         evlist->workload.pid = fork();
 792         if (evlist->workload.pid < 0) {
 793                 perror("failed to fork");
 794                 goto out_close_pipes;
 795         }
 796
 797         if (!evlist->workload.pid) {
 798                 if (opts->pipe_output)
 799                         dup2(2, 1);
 800
 801                 close(child_ready_pipe[0]);
 802                 close(go_pipe[1]);
 803                 fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
 804
 805                 /*
 806                  * Do a dummy execvp to get the PLT entry resolved,
 807                  * so we avoid the resolver overhead on the real
 808                  * execvp call.
 809                  */
 810                 execvp("", (char **)argv);
 811
 812                 /*
 813                  * Tell the parent we're ready to go
 814                  */
 815                 close(child_ready_pipe[1]);
 816
 817                 /*
 818                  * Wait until the parent tells us to go.
 819                  */
 820                 if (read(go_pipe[0], &bf, 1) == -1)
 821                         perror("unable to read pipe");
 822
 823                 execvp(argv[0], (char **)argv);
 824
 825                 perror(argv[0]);
 826                 kill(getppid(), SIGUSR1);
 827                 exit(-1);
 828         }
 829
 830         if (!opts->system_wide && !opts->target_tid && !opts->target_pid)
 831                 evlist->threads->map[0] = evlist->workload.pid;
 832
 833         close(child_ready_pipe[1]);
 834         close(go_pipe[0]);
 835         /*
 836          * wait for child to settle
 837          */
 838         if (read(child_ready_pipe[0], &bf, 1) == -1) {
 839                 perror("unable to read pipe");
 840                 goto out_close_pipes;
 841         }
 842
 843         evlist->workload.cork_fd = go_pipe[1];
 844         close(child_ready_pipe[0]);
 845         return 0;
 846
 847 out_close_pipes:
 848         close(go_pipe[0]);
 849         close(go_pipe[1]);
 850 out_close_ready_pipe:
 851         close(child_ready_pipe[0]);
 852         close(child_ready_pipe[1]);
 853         return -1;
 854 }
 855
 856 int perf_evlist__start_workload(struct perf_evlist *evlist)
 857 {
 858         if (evlist->workload.cork_fd > 0) {
 859                 /*
 860                  * Remove the cork, let it rip!
 861                  */
 862                 return close(evlist->workload.cork_fd);
 863         }
 864
 865         return 0;
 866 }