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
  21 #include <unistd.h>
  22 #include <sched.h>
  23
  24 static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
  25
  26 static long                     default_interval                =      0;
  27
  28 static int                      nr_cpus                         =      0;
  29 static unsigned int             page_size;
  30 static unsigned int             mmap_pages                      =    128;
  31 static int                      freq                            =   1000;
  32 static int                      output;
  33 static const char               *output_name                    = "perf.data";
  34 static int                      group                           =      0;
  35 static unsigned int             realtime_prio                   =      0;
  36 static int                      raw_samples                     =      0;
  37 static int                      system_wide                     =      0;
  38 static int                      profile_cpu                     =     -1;
  39 static pid_t                    target_pid                      =     -1;
  40 static pid_t                    child_pid                       =     -1;
  41 static int                      inherit                         =      1;
  42 static int                      force                           =      0;
  43 static int                      append_file                     =      0;
  44 static int                      call_graph                      =      0;
  45 static int                      inherit_stat                    =      0;
  46 static int                      no_samples                      =      0;
  47 static int                      sample_address                  =      0;
  48 static int                      multiplex                       =      0;
  49 static int                      multiplex_fd                    =     -1;
  50
  51 static long                     samples                         =      0;
  52 static struct timeval           last_read;
  53 static struct timeval           this_read;
  54
  55 static u64                      bytes_written                   =      0;
  56
  57 static struct pollfd            event_array[MAX_NR_CPUS * MAX_COUNTERS];
  58
  59 static int                      nr_poll                         =      0;
  60 static int                      nr_cpu                          =      0;
  61
  62 static int                      file_new                        =      1;
  63
  64 struct perf_header              *header                         =   NULL;
  65
  66 struct mmap_data {
  67         int                     counter;
  68         void                    *base;
  69         unsigned int            mask;
  70         unsigned int            prev;
  71 };
  72
  73 static struct mmap_data         mmap_array[MAX_NR_CPUS][MAX_COUNTERS];
  74
  75 static unsigned long mmap_read_head(struct mmap_data *md)
  76 {
  77         struct perf_event_mmap_page *pc = md->base;
  78         long head;
  79
  80         head = pc->data_head;
  81         rmb();
  82
  83         return head;
  84 }
  85
  86 static void mmap_write_tail(struct mmap_data *md, unsigned long tail)
  87 {
  88         struct perf_event_mmap_page *pc = md->base;
  89
  90         /*
  91          * ensure all reads are done before we write the tail out.
  92          */
  93         /* mb(); */
  94         pc->data_tail = tail;
  95 }
  96
  97 static void write_output(void *buf, size_t size)
  98 {
  99         while (size) {
 100                 int ret = write(output, buf, size);
 101
 102                 if (ret < 0)
 103                         die("failed to write");
 104
 105                 size -= ret;
 106                 buf += ret;
 107
 108                 bytes_written += ret;
 109         }
 110 }
 111
 112 static void mmap_read(struct mmap_data *md)
 113 {
 114         unsigned int head = mmap_read_head(md);
 115         unsigned int old = md->prev;
 116         unsigned char *data = md->base + page_size;
 117         unsigned long size;
 118         void *buf;
 119         int diff;
 120
 121         gettimeofday(&this_read, NULL);
 122
 123         /*
 124          * If we're further behind than half the buffer, there's a chance
 125          * the writer will bite our tail and mess up the samples under us.
 126          *
 127          * If we somehow ended up ahead of the head, we got messed up.
 128          *
 129          * In either case, truncate and restart at head.
 130          */
 131         diff = head - old;
 132         if (diff < 0) {
 133                 struct timeval iv;
 134                 unsigned long msecs;
 135
 136                 timersub(&this_read, &last_read, &iv);
 137                 msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
 138
 139                 fprintf(stderr, "WARNING: failed to keep up with mmap data."
 140                                 "  Last read %lu msecs ago.\n", msecs);
 141
 142                 /*
 143                  * head points to a known good entry, start there.
 144                  */
 145                 old = head;
 146         }
 147
 148         last_read = this_read;
 149
 150         if (old != head)
 151                 samples++;
 152
 153         size = head - old;
 154
 155         if ((old & md->mask) + size != (head & md->mask)) {
 156                 buf = &data[old & md->mask];
 157                 size = md->mask + 1 - (old & md->mask);
 158                 old += size;
 159
 160                 write_output(buf, size);
 161         }
 162
 163         buf = &data[old & md->mask];
 164         size = head - old;
 165         old += size;
 166
 167         write_output(buf, size);
 168
 169         md->prev = old;
 170         mmap_write_tail(md, old);
 171 }
 172
 173 static volatile int done = 0;
 174 static volatile int signr = -1;
 175
 176 static void sig_handler(int sig)
 177 {
 178         done = 1;
 179         signr = sig;
 180 }
 181
 182 static void sig_atexit(void)
 183 {
 184         if (child_pid != -1)
 185                 kill(child_pid, SIGTERM);
 186
 187         if (signr == -1)
 188                 return;
 189
 190         signal(signr, SIG_DFL);
 191         kill(getpid(), signr);
 192 }
 193
 194 static pid_t pid_synthesize_comm_event(pid_t pid, int full)
 195 {
 196         struct comm_event comm_ev;
 197         char filename[PATH_MAX];
 198         char bf[BUFSIZ];
 199         FILE *fp;
 200         size_t size = 0;
 201         DIR *tasks;
 202         struct dirent dirent, *next;
 203         pid_t tgid = 0;
 204
 205         snprintf(filename, sizeof(filename), "/proc/%d/status", pid);
 206
 207         fp = fopen(filename, "r");
 208         if (fp == NULL) {
 209 out_race:
 210                 /*
 211                  * We raced with a task exiting - just return:
 212                  */
 213                 if (verbose)
 214                         fprintf(stderr, "couldn't open %s\n", filename);
 215                 return 0;
 216         }
 217
 218         memset(&comm_ev, 0, sizeof(comm_ev));
 219         while (!comm_ev.comm[0] || !comm_ev.pid) {
 220                 if (fgets(bf, sizeof(bf), fp) == NULL)
 221                         goto out_failure;
 222
 223                 if (memcmp(bf, "Name:", 5) == 0) {
 224                         char *name = bf + 5;
 225                         while (*name && isspace(*name))
 226                                 ++name;
 227                         size = strlen(name) - 1;
 228                         memcpy(comm_ev.comm, name, size++);
 229                 } else if (memcmp(bf, "Tgid:", 5) == 0) {
 230                         char *tgids = bf + 5;
 231                         while (*tgids && isspace(*tgids))
 232                                 ++tgids;
 233                         tgid = comm_ev.pid = atoi(tgids);
 234                 }
 235         }
 236
 237         comm_ev.header.type = PERF_RECORD_COMM;
 238         size = ALIGN(size, sizeof(u64));
 239         comm_ev.header.size = sizeof(comm_ev) - (sizeof(comm_ev.comm) - size);
 240
 241         if (!full) {
 242                 comm_ev.tid = pid;
 243
 244                 write_output(&comm_ev, comm_ev.header.size);
 245                 goto out_fclose;
 246         }
 247
 248         snprintf(filename, sizeof(filename), "/proc/%d/task", pid);
 249
 250         tasks = opendir(filename);
 251         if (tasks == NULL)
 252                 goto out_race;
 253
 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         char *filter = filters[counter];
 379         struct perf_event_attr *attr = attrs + counter;
 380         struct perf_header_attr *h_attr;
 381         int track = !counter; /* only the first counter needs these */
 382         int ret;
 383         struct {
 384                 u64 count;
 385                 u64 time_enabled;
 386                 u64 time_running;
 387                 u64 id;
 388         } read_data;
 389
 390         attr->read_format       = PERF_FORMAT_TOTAL_TIME_ENABLED |
 391                                   PERF_FORMAT_TOTAL_TIME_RUNNING |
 392                                   PERF_FORMAT_ID;
 393
 394         attr->sample_type       |= PERF_SAMPLE_IP | PERF_SAMPLE_TID;
 395
 396         if (freq) {
 397                 attr->sample_type       |= PERF_SAMPLE_PERIOD;
 398                 attr->freq              = 1;
 399                 attr->sample_freq       = freq;
 400         }
 401
 402         if (no_samples)
 403                 attr->sample_freq = 0;
 404
 405         if (inherit_stat)
 406                 attr->inherit_stat = 1;
 407
 408         if (sample_address)
 409                 attr->sample_type       |= PERF_SAMPLE_ADDR;
 410
 411         if (call_graph)
 412                 attr->sample_type       |= PERF_SAMPLE_CALLCHAIN;
 413
 414         if (raw_samples) {
 415                 attr->sample_type       |= PERF_SAMPLE_TIME;
 416                 attr->sample_type       |= PERF_SAMPLE_RAW;
 417                 attr->sample_type       |= PERF_SAMPLE_CPU;
 418         }
 419
 420         attr->mmap              = track;
 421         attr->comm              = track;
 422         attr->inherit           = (cpu < 0) && inherit;
 423         attr->disabled          = 1;
 424
 425 try_again:
 426         fd[nr_cpu][counter] = sys_perf_event_open(attr, pid, cpu, group_fd, 0);
 427
 428         if (fd[nr_cpu][counter] < 0) {
 429                 int err = errno;
 430
 431                 if (err == EPERM)
 432                         die("Permission error - are you root?\n");
 433                 else if (err ==  ENODEV && profile_cpu != -1)
 434                         die("No such device - did you specify an out-of-range profile CPU?\n");
 435
 436                 /*
 437                  * If it's cycles then fall back to hrtimer
 438                  * based cpu-clock-tick sw counter, which
 439                  * is always available even if no PMU support:
 440                  */
 441                 if (attr->type == PERF_TYPE_HARDWARE
 442                         && attr->config == PERF_COUNT_HW_CPU_CYCLES) {
 443
 444                         if (verbose)
 445                                 warning(" ... trying to fall back to cpu-clock-ticks\n");
 446                         attr->type = PERF_TYPE_SOFTWARE;
 447                         attr->config = PERF_COUNT_SW_CPU_CLOCK;
 448                         goto try_again;
 449                 }
 450                 printf("\n");
 451                 error("perfcounter syscall returned with %d (%s)\n",
 452                         fd[nr_cpu][counter], strerror(err));
 453                 die("No CONFIG_PERF_EVENTS=y kernel support configured?\n");
 454                 exit(-1);
 455         }
 456
 457         h_attr = get_header_attr(attr, counter);
 458
 459         if (!file_new) {
 460                 if (memcmp(&h_attr->attr, attr, sizeof(*attr))) {
 461                         fprintf(stderr, "incompatible append\n");
 462                         exit(-1);
 463                 }
 464         }
 465
 466         if (read(fd[nr_cpu][counter], &read_data, sizeof(read_data)) == -1) {
 467                 perror("Unable to read perf file descriptor\n");
 468                 exit(-1);
 469         }
 470
 471         perf_header_attr__add_id(h_attr, read_data.id);
 472
 473         assert(fd[nr_cpu][counter] >= 0);
 474         fcntl(fd[nr_cpu][counter], F_SETFL, O_NONBLOCK);
 475
 476         /*
 477          * First counter acts as the group leader:
 478          */
 479         if (group && group_fd == -1)
 480                 group_fd = fd[nr_cpu][counter];
 481         if (multiplex && multiplex_fd == -1)
 482                 multiplex_fd = fd[nr_cpu][counter];
 483
 484         if (multiplex && fd[nr_cpu][counter] != multiplex_fd) {
 485
 486                 ret = ioctl(fd[nr_cpu][counter], PERF_EVENT_IOC_SET_OUTPUT, multiplex_fd);
 487                 assert(ret != -1);
 488         } else {
 489                 event_array[nr_poll].fd = fd[nr_cpu][counter];
 490                 event_array[nr_poll].events = POLLIN;
 491                 nr_poll++;
 492
 493                 mmap_array[nr_cpu][counter].counter = counter;
 494                 mmap_array[nr_cpu][counter].prev = 0;
 495                 mmap_array[nr_cpu][counter].mask = mmap_pages*page_size - 1;
 496                 mmap_array[nr_cpu][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
 497                                 PROT_READ|PROT_WRITE, MAP_SHARED, fd[nr_cpu][counter], 0);
 498                 if (mmap_array[nr_cpu][counter].base == MAP_FAILED) {
 499                         error("failed to mmap with %d (%s)\n", errno, strerror(errno));
 500                         exit(-1);
 501                 }
 502         }
 503
 504         if (filter != NULL) {
 505                 ret = ioctl(fd[nr_cpu][counter],
 506                             PERF_EVENT_IOC_SET_FILTER, filter);
 507                 if (ret) {
 508                         error("failed to set filter with %d (%s)\n", errno,
 509                               strerror(errno));
 510                         exit(-1);
 511                 }
 512         }
 513
 514         ioctl(fd[nr_cpu][counter], PERF_EVENT_IOC_ENABLE);
 515 }
 516
 517 static void open_counters(int cpu, pid_t pid)
 518 {
 519         int counter;
 520
 521         group_fd = -1;
 522         for (counter = 0; counter < nr_counters; counter++)
 523                 create_counter(counter, cpu, pid);
 524
 525         nr_cpu++;
 526 }
 527
 528 static void atexit_header(void)
 529 {
 530         header->data_size += bytes_written;
 531
 532         perf_header__write(header, output);
 533 }
 534
 535 static int __cmd_record(int argc, const char **argv)
 536 {
 537         int i, counter;
 538         struct stat st;
 539         pid_t pid = 0;
 540         int flags;
 541         int ret;
 542         unsigned long waking = 0;
 543
 544         page_size = sysconf(_SC_PAGE_SIZE);
 545         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 546         assert(nr_cpus <= MAX_NR_CPUS);
 547         assert(nr_cpus >= 0);
 548
 549         atexit(sig_atexit);
 550         signal(SIGCHLD, sig_handler);
 551         signal(SIGINT, sig_handler);
 552
 553         if (!stat(output_name, &st) && st.st_size) {
 554                 if (!force && !append_file) {
 555                         fprintf(stderr, "Error, output file %s exists, use -A to append or -f to overwrite.\n",
 556                                         output_name);
 557                         exit(-1);
 558                 }
 559         } else {
 560                 append_file = 0;
 561         }
 562
 563         flags = O_CREAT|O_RDWR;
 564         if (append_file)
 565                 file_new = 0;
 566         else
 567                 flags |= O_TRUNC;
 568
 569         output = open(output_name, flags, S_IRUSR|S_IWUSR);
 570         if (output < 0) {
 571                 perror("failed to create output file");
 572                 exit(-1);
 573         }
 574
 575         if (!file_new)
 576                 header = perf_header__read(output);
 577         else
 578                 header = perf_header__new();
 579
 580         if (raw_samples) {
 581                 perf_header__feat_trace_info(header);
 582         } else {
 583                 for (i = 0; i < nr_counters; i++) {
 584                         if (attrs[i].sample_type & PERF_SAMPLE_RAW) {
 585                                 perf_header__feat_trace_info(header);
 586                                 break;
 587                         }
 588                 }
 589         }
 590
 591         atexit(atexit_header);
 592
 593         if (!system_wide) {
 594                 pid = target_pid;
 595                 if (pid == -1)
 596                         pid = getpid();
 597
 598                 open_counters(profile_cpu, pid);
 599         } else {
 600                 if (profile_cpu != -1) {
 601                         open_counters(profile_cpu, target_pid);
 602                 } else {
 603                         for (i = 0; i < nr_cpus; i++)
 604                                 open_counters(i, target_pid);
 605                 }
 606         }
 607
 608         if (file_new)
 609                 perf_header__write(header, output);
 610
 611         if (!system_wide) {
 612                 pid_t tgid = pid_synthesize_comm_event(pid, 0);
 613                 pid_synthesize_mmap_samples(pid, tgid);
 614         } else
 615                 synthesize_all();
 616
 617         if (target_pid == -1 && argc) {
 618                 pid = fork();
 619                 if (pid < 0)
 620                         perror("failed to fork");
 621
 622                 if (!pid) {
 623                         if (execvp(argv[0], (char **)argv)) {
 624                                 perror(argv[0]);
 625                                 exit(-1);
 626                         }
 627                 }
 628
 629                 child_pid = pid;
 630         }
 631
 632         if (realtime_prio) {
 633                 struct sched_param param;
 634
 635                 param.sched_priority = realtime_prio;
 636                 if (sched_setscheduler(0, SCHED_FIFO, &param)) {
 637                         pr_err("Could not set realtime priority.\n");
 638                         exit(-1);
 639                 }
 640         }
 641
 642         for (;;) {
 643                 int hits = samples;
 644
 645                 for (i = 0; i < nr_cpu; i++) {
 646                         for (counter = 0; counter < nr_counters; counter++) {
 647                                 if (mmap_array[i][counter].base)
 648                                         mmap_read(&mmap_array[i][counter]);
 649                         }
 650                 }
 651
 652                 if (hits == samples) {
 653                         if (done)
 654                                 break;
 655                         ret = poll(event_array, nr_poll, -1);
 656                         waking++;
 657                 }
 658
 659                 if (done) {
 660                         for (i = 0; i < nr_cpu; i++) {
 661                                 for (counter = 0; counter < nr_counters; counter++)
 662                                         ioctl(fd[i][counter], PERF_EVENT_IOC_DISABLE);
 663                         }
 664                 }
 665         }
 666
 667         fprintf(stderr, "[ perf record: Woken up %ld times to write data ]\n", waking);
 668
 669         /*
 670          * Approximate RIP event size: 24 bytes.
 671          */
 672         fprintf(stderr,
 673                 "[ perf record: Captured and wrote %.3f MB %s (~%lld samples) ]\n",
 674                 (double)bytes_written / 1024.0 / 1024.0,
 675                 output_name,
 676                 bytes_written / 24);
 677
 678         return 0;
 679 }
 680
 681 static const char * const record_usage[] = {
 682         "perf record [<options>] [<command>]",
 683         "perf record [<options>] -- <command> [<options>]",
 684         NULL
 685 };
 686
 687 static const struct option options[] = {
 688         OPT_CALLBACK('e', "event", NULL, "event",
 689                      "event selector. use 'perf list' to list available events",
 690                      parse_events),
 691         OPT_CALLBACK(0, "filter", NULL, "filter",
 692                      "event filter", parse_filter),
 693         OPT_INTEGER('p', "pid", &target_pid,
 694                     "record events on existing pid"),
 695         OPT_INTEGER('r', "realtime", &realtime_prio,
 696                     "collect data with this RT SCHED_FIFO priority"),
 697         OPT_BOOLEAN('R', "raw-samples", &raw_samples,
 698                     "collect raw sample records from all opened counters"),
 699         OPT_BOOLEAN('a', "all-cpus", &system_wide,
 700                             "system-wide collection from all CPUs"),
 701         OPT_BOOLEAN('A', "append", &append_file,
 702                             "append to the output file to do incremental profiling"),
 703         OPT_INTEGER('C', "profile_cpu", &profile_cpu,
 704                             "CPU to profile on"),
 705         OPT_BOOLEAN('f', "force", &force,
 706                         "overwrite existing data file"),
 707         OPT_LONG('c', "count", &default_interval,
 708                     "event period to sample"),
 709         OPT_STRING('o', "output", &output_name, "file",
 710                     "output file name"),
 711         OPT_BOOLEAN('i', "inherit", &inherit,
 712                     "child tasks inherit counters"),
 713         OPT_INTEGER('F', "freq", &freq,
 714                     "profile at this frequency"),
 715         OPT_INTEGER('m', "mmap-pages", &mmap_pages,
 716                     "number of mmap data pages"),
 717         OPT_BOOLEAN('g', "call-graph", &call_graph,
 718                     "do call-graph (stack chain/backtrace) recording"),
 719         OPT_BOOLEAN('v', "verbose", &verbose,
 720                     "be more verbose (show counter open errors, etc)"),
 721         OPT_BOOLEAN('s', "stat", &inherit_stat,
 722                     "per thread counts"),
 723         OPT_BOOLEAN('d', "data", &sample_address,
 724                     "Sample addresses"),
 725         OPT_BOOLEAN('n', "no-samples", &no_samples,
 726                     "don't sample"),
 727         OPT_BOOLEAN('M', "multiplex", &multiplex,
 728                     "multiplex counter output in a single channel"),
 729         OPT_END()
 730 };
 731
 732 int cmd_record(int argc, const char **argv, const char *prefix __used)
 733 {
 734         int counter;
 735
 736         argc = parse_options(argc, argv, options, record_usage,
 737                 PARSE_OPT_STOP_AT_NON_OPTION);
 738         if (!argc && target_pid == -1 && !system_wide)
 739                 usage_with_options(record_usage, options);
 740
 741         if (!nr_counters) {
 742                 nr_counters     = 1;
 743                 attrs[0].type   = PERF_TYPE_HARDWARE;
 744                 attrs[0].config = PERF_COUNT_HW_CPU_CYCLES;
 745         }
 746
 747         /*
 748          * User specified count overrides default frequency.
 749          */
 750         if (default_interval)
 751                 freq = 0;
 752         else if (freq) {
 753                 default_interval = freq;
 754         } else {
 755                 fprintf(stderr, "frequency and count are zero, aborting\n");
 756                 exit(EXIT_FAILURE);
 757         }
 758
 759         for (counter = 0; counter < nr_counters; counter++) {
 760                 if (attrs[counter].sample_period)
 761                         continue;
 762
 763                 attrs[counter].sample_period = default_interval;
 764         }
 765
 766         return __cmd_record(argc, argv);
 767 }