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