SAFE public projects git trees. - safe/jmp/linux-2.6/blob - tools/perf/builtin-record.c

   1 /*
   2  * builtin-record.c
   3  *
   4  * Builtin record command: Record the profile of a workload
   5  * (or a CPU, or a PID) into the perf.data output file - for
   6  * later analysis via perf report.
   7  */
   8 #include "builtin.h"
   9
  10 #include "perf.h"
  11
  12 #include "util/util.h"
  13 #include "util/parse-options.h"
  14 #include "util/parse-events.h"
  15 #include "util/string.h"
  16
  17 #include "util/header.h"
  18 #include "util/event.h"
  19 #include "util/debug.h"
  20 #include "util/trace-event.h"
  21
  22 #include <unistd.h>
  23 #include <sched.h>
  24
  25 #define ALIGN(x, a)             __ALIGN_MASK(x, (typeof(x))(a)-1)
  26 #define __ALIGN_MASK(x, mask)   (((x)+(mask))&~(mask))
  27
  28 static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
  29
  30 static long                     default_interval                = 100000;
  31
  32 static int                      nr_cpus                         = 0;
  33 static unsigned int             page_size;
  34 static unsigned int             mmap_pages                      = 128;
  35 static int                      freq                            = 0;
  36 static int                      output;
  37 static const char               *output_name                    = "perf.data";
  38 static int                      group                           = 0;
  39 static unsigned int             realtime_prio                   = 0;
  40 static int                      raw_samples                     = 0;
  41 static int                      system_wide                     = 0;
  42 static int                      profile_cpu                     = -1;
  43 static pid_t                    target_pid                      = -1;
  44 static pid_t                    child_pid                       = -1;
  45 static int                      inherit                         = 1;
  46 static int                      force                           = 0;
  47 static int                      append_file                     = 0;
  48 static int                      call_graph                      = 0;
  49 static int                      inherit_stat                    = 0;
  50 static int                      no_samples                      = 0;
  51 static int                      sample_address                  = 0;
  52 static int                      multiplex                       = 0;
  53 static int                      multiplex_fd                    = -1;
  54
  55 static long                     samples;
  56 static struct timeval           last_read;
  57 static struct timeval           this_read;
  58
  59 static u64                      bytes_written;
  60
  61 static struct pollfd            event_array[MAX_NR_CPUS * MAX_COUNTERS];
  62
  63 static int                      nr_poll;
  64 static int                      nr_cpu;
  65
  66 static int                      file_new = 1;
  67
  68 struct perf_header              *header;
  69
  70 struct mmap_data {
  71         int                     counter;
  72         void                    *base;
  73         unsigned int            mask;
  74         unsigned int            prev;
  75 };
  76
  77 static struct mmap_data         mmap_array[MAX_NR_CPUS][MAX_COUNTERS];
  78
  79 static unsigned long mmap_read_head(struct mmap_data *md)
  80 {
  81         struct perf_event_mmap_page *pc = md->base;
  82         long head;
  83
  84         head = pc->data_head;
  85         rmb();
  86
  87         return head;
  88 }
  89
  90 static void mmap_write_tail(struct mmap_data *md, unsigned long tail)
  91 {
  92         struct perf_event_mmap_page *pc = md->base;
  93
  94         /*
  95          * ensure all reads are done before we write the tail out.
  96          */
  97         /* mb(); */
  98         pc->data_tail = tail;
  99 }
 100
 101 static void write_output(void *buf, size_t size)
 102 {
 103         while (size) {
 104                 int ret = write(output, buf, size);
 105
 106                 if (ret < 0)
 107                         die("failed to write");
 108
 109                 size -= ret;
 110                 buf += ret;
 111
 112                 bytes_written += ret;
 113         }
 114 }
 115
 116 static void mmap_read(struct mmap_data *md)
 117 {
 118         unsigned int head = mmap_read_head(md);
 119         unsigned int old = md->prev;
 120         unsigned char *data = md->base + page_size;
 121         unsigned long size;
 122         void *buf;
 123         int diff;
 124
 125         gettimeofday(&this_read, NULL);
 126
 127         /*
 128          * If we're further behind than half the buffer, there's a chance
 129          * the writer will bite our tail and mess up the samples under us.
 130          *
 131          * If we somehow ended up ahead of the head, we got messed up.
 132          *
 133          * In either case, truncate and restart at head.
 134          */
 135         diff = head - old;
 136         if (diff < 0) {
 137                 struct timeval iv;
 138                 unsigned long msecs;
 139
 140                 timersub(&this_read, &last_read, &iv);
 141                 msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
 142
 143                 fprintf(stderr, "WARNING: failed to keep up with mmap data."
 144                                 "  Last read %lu msecs ago.\n", msecs);
 145
 146                 /*
 147                  * head points to a known good entry, start there.
 148                  */
 149                 old = head;
 150         }
 151
 152         last_read = this_read;
 153
 154         if (old != head)
 155                 samples++;
 156
 157         size = head - old;
 158
 159         if ((old & md->mask) + size != (head & md->mask)) {
 160                 buf = &data[old & md->mask];
 161                 size = md->mask + 1 - (old & md->mask);
 162                 old += size;
 163
 164                 write_output(buf, size);
 165         }
 166
 167         buf = &data[old & md->mask];
 168         size = head - old;
 169         old += size;
 170
 171         write_output(buf, size);
 172
 173         md->prev = old;
 174         mmap_write_tail(md, old);
 175 }
 176
 177 static volatile int done = 0;
 178 static volatile int signr = -1;
 179
 180 static void sig_handler(int sig)
 181 {
 182         done = 1;
 183         signr = sig;
 184 }
 185
 186 static void sig_atexit(void)
 187 {
 188         if (child_pid != -1)
 189                 kill(child_pid, SIGTERM);
 190
 191         if (signr == -1)
 192                 return;
 193
 194         signal(signr, SIG_DFL);
 195         kill(getpid(), signr);
 196 }
 197
 198 static pid_t pid_synthesize_comm_event(pid_t pid, int full)
 199 {
 200         struct comm_event comm_ev;
 201         char filename[PATH_MAX];
 202         char bf[BUFSIZ];
 203         FILE *fp;
 204         size_t size = 0;
 205         DIR *tasks;
 206         struct dirent dirent, *next;
 207         pid_t tgid = 0;
 208
 209         snprintf(filename, sizeof(filename), "/proc/%d/status", pid);
 210
 211         fp = fopen(filename, "r");
 212         if (fp == NULL) {
 213                 /*
 214                  * We raced with a task exiting - just return:
 215                  */
 216                 if (verbose)
 217                         fprintf(stderr, "couldn't open %s\n", filename);
 218                 return 0;
 219         }
 220
 221         memset(&comm_ev, 0, sizeof(comm_ev));
 222         while (!comm_ev.comm[0] || !comm_ev.pid) {
 223                 if (fgets(bf, sizeof(bf), fp) == NULL)
 224                         goto out_failure;
 225
 226                 if (memcmp(bf, "Name:", 5) == 0) {
 227                         char *name = bf + 5;
 228                         while (*name && isspace(*name))
 229                                 ++name;
 230                         size = strlen(name) - 1;
 231                         memcpy(comm_ev.comm, name, size++);
 232                 } else if (memcmp(bf, "Tgid:", 5) == 0) {
 233                         char *tgids = bf + 5;
 234                         while (*tgids && isspace(*tgids))
 235                                 ++tgids;
 236                         tgid = comm_ev.pid = atoi(tgids);
 237                 }
 238         }
 239
 240         comm_ev.header.type = PERF_RECORD_COMM;
 241         size = ALIGN(size, sizeof(u64));
 242         comm_ev.header.size = sizeof(comm_ev) - (sizeof(comm_ev.comm) - size);
 243
 244         if (!full) {
 245                 comm_ev.tid = pid;
 246
 247                 write_output(&comm_ev, comm_ev.header.size);
 248                 goto out_fclose;
 249         }
 250
 251         snprintf(filename, sizeof(filename), "/proc/%d/task", pid);
 252
 253         tasks = opendir(filename);
 254         while (!readdir_r(tasks, &dirent, &next) && next) {
 255                 char *end;
 256                 pid = strtol(dirent.d_name, &end, 10);
 257                 if (*end)
 258                         continue;
 259
 260                 comm_ev.tid = pid;
 261
 262                 write_output(&comm_ev, comm_ev.header.size);
 263         }
 264         closedir(tasks);
 265
 266 out_fclose:
 267         fclose(fp);
 268         return tgid;
 269
 270 out_failure:
 271         fprintf(stderr, "couldn't get COMM and pgid, malformed %s\n",
 272                 filename);
 273         exit(EXIT_FAILURE);
 274 }
 275
 276 static void pid_synthesize_mmap_samples(pid_t pid, pid_t tgid)
 277 {
 278         char filename[PATH_MAX];
 279         FILE *fp;
 280
 281         snprintf(filename, sizeof(filename), "/proc/%d/maps", pid);
 282
 283         fp = fopen(filename, "r");
 284         if (fp == NULL) {
 285                 /*
 286                  * We raced with a task exiting - just return:
 287                  */
 288                 if (verbose)
 289                         fprintf(stderr, "couldn't open %s\n", filename);
 290                 return;
 291         }
 292         while (1) {
 293                 char bf[BUFSIZ], *pbf = bf;
 294                 struct mmap_event mmap_ev = {
 295                         .header = { .type = PERF_RECORD_MMAP },
 296                 };
 297                 int n;
 298                 size_t size;
 299                 if (fgets(bf, sizeof(bf), fp) == NULL)
 300                         break;
 301
 302                 /* 00400000-0040c000 r-xp 00000000 fd:01 41038  /bin/cat */
 303                 n = hex2u64(pbf, &mmap_ev.start);
 304                 if (n < 0)
 305                         continue;
 306                 pbf += n + 1;
 307                 n = hex2u64(pbf, &mmap_ev.len);
 308                 if (n < 0)
 309                         continue;
 310                 pbf += n + 3;
 311                 if (*pbf == 'x') { /* vm_exec */
 312                         char *execname = strchr(bf, '/');
 313
 314                         /* Catch VDSO */
 315                         if (execname == NULL)
 316                                 execname = strstr(bf, "[vdso]");
 317
 318                         if (execname == NULL)
 319                                 continue;
 320
 321                         size = strlen(execname);
 322                         execname[size - 1] = '\0'; /* Remove \n */
 323                         memcpy(mmap_ev.filename, execname, size);
 324                         size = ALIGN(size, sizeof(u64));
 325                         mmap_ev.len -= mmap_ev.start;
 326                         mmap_ev.header.size = (sizeof(mmap_ev) -
 327                                                (sizeof(mmap_ev.filename) - size));
 328                         mmap_ev.pid = tgid;
 329                         mmap_ev.tid = pid;
 330
 331                         write_output(&mmap_ev, mmap_ev.header.size);
 332                 }
 333         }
 334
 335         fclose(fp);
 336 }
 337
 338 static void synthesize_all(void)
 339 {
 340         DIR *proc;
 341         struct dirent dirent, *next;
 342
 343         proc = opendir("/proc");
 344
 345         while (!readdir_r(proc, &dirent, &next) && next) {
 346                 char *end;
 347                 pid_t pid, tgid;
 348
 349                 pid = strtol(dirent.d_name, &end, 10);
 350                 if (*end) /* only interested in proper numerical dirents */
 351                         continue;
 352
 353                 tgid = pid_synthesize_comm_event(pid, 1);
 354                 pid_synthesize_mmap_samples(pid, tgid);
 355         }
 356
 357         closedir(proc);
 358 }
 359
 360 static int group_fd;
 361
 362 static struct perf_header_attr *get_header_attr(struct perf_event_attr *a, int nr)
 363 {
 364         struct perf_header_attr *h_attr;
 365
 366         if (nr < header->attrs) {
 367                 h_attr = header->attr[nr];
 368         } else {
 369                 h_attr = perf_header_attr__new(a);
 370                 perf_header__add_attr(header, h_attr);
 371         }
 372
 373         return h_attr;
 374 }
 375
 376 static void create_counter(int counter, int cpu, pid_t pid)
 377 {
 378         struct perf_event_attr *attr = attrs + counter;
 379         struct perf_header_attr *h_attr;
 380         int track = !counter; /* only the first counter needs these */
 381         struct {
 382                 u64 count;
 383                 u64 time_enabled;
 384                 u64 time_running;
 385                 u64 id;
 386         } read_data;
 387
 388         attr->read_format       = PERF_FORMAT_TOTAL_TIME_ENABLED |
 389                                   PERF_FORMAT_TOTAL_TIME_RUNNING |
 390                                   PERF_FORMAT_ID;
 391
 392         attr->sample_type       |= PERF_SAMPLE_IP | PERF_SAMPLE_TID;
 393
 394         if (freq) {
 395                 attr->sample_type       |= PERF_SAMPLE_PERIOD;
 396                 attr->freq              = 1;
 397                 attr->sample_freq       = freq;
 398         }
 399
 400         if (no_samples)
 401                 attr->sample_freq = 0;
 402
 403         if (inherit_stat)
 404                 attr->inherit_stat = 1;
 405
 406         if (sample_address)
 407                 attr->sample_type       |= PERF_SAMPLE_ADDR;
 408
 409         if (call_graph)
 410                 attr->sample_type       |= PERF_SAMPLE_CALLCHAIN;
 411
 412         if (raw_samples) {
 413                 attr->sample_type       |= PERF_SAMPLE_TIME;
 414                 attr->sample_type       |= PERF_SAMPLE_RAW;
 415                 attr->sample_type       |= PERF_SAMPLE_CPU;
 416         }
 417
 418         attr->mmap              = track;
 419         attr->comm              = track;
 420         attr->inherit           = (cpu < 0) && inherit;
 421         attr->disabled          = 1;
 422
 423 try_again:
 424         fd[nr_cpu][counter] = sys_perf_event_open(attr, pid, cpu, group_fd, 0);
 425
 426         if (fd[nr_cpu][counter] < 0) {
 427                 int err = errno;
 428
 429                 if (err == EPERM)
 430                         die("Permission error - are you root?\n");
 431                 else if (err ==  ENODEV && profile_cpu != -1)
 432                         die("No such device - did you specify an out-of-range profile CPU?\n");
 433
 434                 /*
 435                  * If it's cycles then fall back to hrtimer
 436                  * based cpu-clock-tick sw counter, which
 437                  * is always available even if no PMU support:
 438                  */
 439                 if (attr->type == PERF_TYPE_HARDWARE
 440                         && attr->config == PERF_COUNT_HW_CPU_CYCLES) {
 441
 442                         if (verbose)
 443                                 warning(" ... trying to fall back to cpu-clock-ticks\n");
 444                         attr->type = PERF_TYPE_SOFTWARE;
 445                         attr->config = PERF_COUNT_SW_CPU_CLOCK;
 446                         goto try_again;
 447                 }
 448                 printf("\n");
 449                 error("perfcounter syscall returned with %d (%s)\n",
 450                         fd[nr_cpu][counter], strerror(err));
 451                 die("No CONFIG_PERF_EVENTS=y kernel support configured?\n");
 452                 exit(-1);
 453         }
 454
 455         h_attr = get_header_attr(attr, counter);
 456
 457         if (!file_new) {
 458                 if (memcmp(&h_attr->attr, attr, sizeof(*attr))) {
 459                         fprintf(stderr, "incompatible append\n");
 460                         exit(-1);
 461                 }
 462         }
 463
 464         if (read(fd[nr_cpu][counter], &read_data, sizeof(read_data)) == -1) {
 465                 perror("Unable to read perf file descriptor\n");
 466                 exit(-1);
 467         }
 468
 469         perf_header_attr__add_id(h_attr, read_data.id);
 470
 471         assert(fd[nr_cpu][counter] >= 0);
 472         fcntl(fd[nr_cpu][counter], F_SETFL, O_NONBLOCK);
 473
 474         /*
 475          * First counter acts as the group leader:
 476          */
 477         if (group && group_fd == -1)
 478                 group_fd = fd[nr_cpu][counter];
 479         if (multiplex && multiplex_fd == -1)
 480                 multiplex_fd = fd[nr_cpu][counter];
 481
 482         if (multiplex && fd[nr_cpu][counter] != multiplex_fd) {
 483                 int ret;
 484
 485                 ret = ioctl(fd[nr_cpu][counter], PERF_EVENT_IOC_SET_OUTPUT, multiplex_fd);
 486                 assert(ret != -1);
 487         } else {
 488                 event_array[nr_poll].fd = fd[nr_cpu][counter];
 489                 event_array[nr_poll].events = POLLIN;
 490                 nr_poll++;
 491
 492                 mmap_array[nr_cpu][counter].counter = counter;
 493                 mmap_array[nr_cpu][counter].prev = 0;
 494                 mmap_array[nr_cpu][counter].mask = mmap_pages*page_size - 1;
 495                 mmap_array[nr_cpu][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
 496                                 PROT_READ|PROT_WRITE, MAP_SHARED, fd[nr_cpu][counter], 0);
 497                 if (mmap_array[nr_cpu][counter].base == MAP_FAILED) {
 498                         error("failed to mmap with %d (%s)\n", errno, strerror(errno));
 499                         exit(-1);
 500                 }
 501         }
 502
 503         ioctl(fd[nr_cpu][counter], PERF_EVENT_IOC_ENABLE);
 504 }
 505
 506 static void open_counters(int cpu, pid_t pid)
 507 {
 508         int counter;
 509
 510         group_fd = -1;
 511         for (counter = 0; counter < nr_counters; counter++)
 512                 create_counter(counter, cpu, pid);
 513
 514         nr_cpu++;
 515 }
 516
 517 static void atexit_header(void)
 518 {
 519         header->data_size += bytes_written;
 520
 521         perf_header__write(header, output);
 522 }
 523
 524 static int __cmd_record(int argc, const char **argv)
 525 {
 526         int i, counter;
 527         struct stat st;
 528         pid_t pid = 0;
 529         int flags;
 530         int ret;
 531         unsigned long waking = 0;
 532
 533         page_size = sysconf(_SC_PAGE_SIZE);
 534         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 535         assert(nr_cpus <= MAX_NR_CPUS);
 536         assert(nr_cpus >= 0);
 537
 538         atexit(sig_atexit);
 539         signal(SIGCHLD, sig_handler);
 540         signal(SIGINT, sig_handler);
 541
 542         if (!stat(output_name, &st) && st.st_size) {
 543                 if (!force && !append_file) {
 544                         fprintf(stderr, "Error, output file %s exists, use -A to append or -f to overwrite.\n",
 545                                         output_name);
 546                         exit(-1);
 547                 }
 548         } else {
 549                 append_file = 0;
 550         }
 551
 552         flags = O_CREAT|O_RDWR;
 553         if (append_file)
 554                 file_new = 0;
 555         else
 556                 flags |= O_TRUNC;
 557
 558         output = open(output_name, flags, S_IRUSR|S_IWUSR);
 559         if (output < 0) {
 560                 perror("failed to create output file");
 561                 exit(-1);
 562         }
 563
 564         if (!file_new)
 565                 header = perf_header__read(output);
 566         else
 567                 header = perf_header__new();
 568
 569
 570         if (raw_samples) {
 571                 read_tracing_data(attrs, nr_counters);
 572         } else {
 573                 for (i = 0; i < nr_counters; i++) {
 574                         if (attrs[i].sample_type & PERF_SAMPLE_RAW) {
 575                                 read_tracing_data(attrs, nr_counters);
 576                                 break;
 577                         }
 578                 }
 579         }
 580         atexit(atexit_header);
 581
 582         if (!system_wide) {
 583                 pid = target_pid;
 584                 if (pid == -1)
 585                         pid = getpid();
 586
 587                 open_counters(profile_cpu, pid);
 588         } else {
 589                 if (profile_cpu != -1) {
 590                         open_counters(profile_cpu, target_pid);
 591                 } else {
 592                         for (i = 0; i < nr_cpus; i++)
 593                                 open_counters(i, target_pid);
 594                 }
 595         }
 596
 597         if (file_new)
 598                 perf_header__write(header, output);
 599
 600         if (!system_wide) {
 601                 pid_t tgid = pid_synthesize_comm_event(pid, 0);
 602                 pid_synthesize_mmap_samples(pid, tgid);
 603         } else
 604                 synthesize_all();
 605
 606         if (target_pid == -1 && argc) {
 607                 pid = fork();
 608                 if (pid < 0)
 609                         perror("failed to fork");
 610
 611                 if (!pid) {
 612                         if (execvp(argv[0], (char **)argv)) {
 613                                 perror(argv[0]);
 614                                 exit(-1);
 615                         }
 616                 }
 617
 618                 child_pid = pid;
 619         }
 620
 621         if (realtime_prio) {
 622                 struct sched_param param;
 623
 624                 param.sched_priority = realtime_prio;
 625                 if (sched_setscheduler(0, SCHED_FIFO, &param)) {
 626                         printf("Could not set realtime priority.\n");
 627                         exit(-1);
 628                 }
 629         }
 630
 631         for (;;) {
 632                 int hits = samples;
 633
 634                 for (i = 0; i < nr_cpu; i++) {
 635                         for (counter = 0; counter < nr_counters; counter++) {
 636                                 if (mmap_array[i][counter].base)
 637                                         mmap_read(&mmap_array[i][counter]);
 638                         }
 639                 }
 640
 641                 if (hits == samples) {
 642                         if (done)
 643                                 break;
 644                         ret = poll(event_array, nr_poll, -1);
 645                         waking++;
 646                 }
 647
 648                 if (done) {
 649                         for (i = 0; i < nr_cpu; i++) {
 650                                 for (counter = 0; counter < nr_counters; counter++)
 651                                         ioctl(fd[i][counter], PERF_EVENT_IOC_DISABLE);
 652                         }
 653                 }
 654         }
 655
 656         fprintf(stderr, "[ perf record: Woken up %ld times to write data ]\n", waking);
 657
 658         /*
 659          * Approximate RIP event size: 24 bytes.
 660          */
 661         fprintf(stderr,
 662                 "[ perf record: Captured and wrote %.3f MB %s (~%lld samples) ]\n",
 663                 (double)bytes_written / 1024.0 / 1024.0,
 664                 output_name,
 665                 bytes_written / 24);
 666
 667         return 0;
 668 }
 669
 670 static const char * const record_usage[] = {
 671         "perf record [<options>] [<command>]",
 672         "perf record [<options>] -- <command> [<options>]",
 673         NULL
 674 };
 675
 676 static const struct option options[] = {
 677         OPT_CALLBACK('e', "event", NULL, "event",
 678                      "event selector. use 'perf list' to list available events",
 679                      parse_events),
 680         OPT_INTEGER('p', "pid", &target_pid,
 681                     "record events on existing pid"),
 682         OPT_INTEGER('r', "realtime", &realtime_prio,
 683                     "collect data with this RT SCHED_FIFO priority"),
 684         OPT_BOOLEAN('R', "raw-samples", &raw_samples,
 685                     "collect raw sample records from all opened counters"),
 686         OPT_BOOLEAN('a', "all-cpus", &system_wide,
 687                             "system-wide collection from all CPUs"),
 688         OPT_BOOLEAN('A', "append", &append_file,
 689                             "append to the output file to do incremental profiling"),
 690         OPT_INTEGER('C', "profile_cpu", &profile_cpu,
 691                             "CPU to profile on"),
 692         OPT_BOOLEAN('f', "force", &force,
 693                         "overwrite existing data file"),
 694         OPT_LONG('c', "count", &default_interval,
 695                     "event period to sample"),
 696         OPT_STRING('o', "output", &output_name, "file",
 697                     "output file name"),
 698         OPT_BOOLEAN('i', "inherit", &inherit,
 699                     "child tasks inherit counters"),
 700         OPT_INTEGER('F', "freq", &freq,
 701                     "profile at this frequency"),
 702         OPT_INTEGER('m', "mmap-pages", &mmap_pages,
 703                     "number of mmap data pages"),
 704         OPT_BOOLEAN('g', "call-graph", &call_graph,
 705                     "do call-graph (stack chain/backtrace) recording"),
 706         OPT_BOOLEAN('v', "verbose", &verbose,
 707                     "be more verbose (show counter open errors, etc)"),
 708         OPT_BOOLEAN('s', "stat", &inherit_stat,
 709                     "per thread counts"),
 710         OPT_BOOLEAN('d', "data", &sample_address,
 711                     "Sample addresses"),
 712         OPT_BOOLEAN('n', "no-samples", &no_samples,
 713                     "don't sample"),
 714         OPT_BOOLEAN('M', "multiplex", &multiplex,
 715                     "multiplex counter output in a single channel"),
 716         OPT_END()
 717 };
 718
 719 int cmd_record(int argc, const char **argv, const char *prefix __used)
 720 {
 721         int counter;
 722
 723         argc = parse_options(argc, argv, options, record_usage,
 724                 PARSE_OPT_STOP_AT_NON_OPTION);
 725         if (!argc && target_pid == -1 && !system_wide)
 726                 usage_with_options(record_usage, options);
 727
 728         if (!nr_counters) {
 729                 nr_counters     = 1;
 730                 attrs[0].type   = PERF_TYPE_HARDWARE;
 731                 attrs[0].config = PERF_COUNT_HW_CPU_CYCLES;
 732         }
 733
 734         for (counter = 0; counter < nr_counters; counter++) {
 735                 if (attrs[counter].sample_period)
 736                         continue;
 737
 738                 attrs[counter].sample_period = default_interval;
 739         }
 740
 741         return __cmd_record(argc, argv);
 742 }