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/session.h"
  21 #include "util/symbol.h"
  22
  23 #include <unistd.h>
  24 #include <sched.h>
  25
  26 static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
  27
  28 static long                     default_interval                =      0;
  29
  30 static int                      nr_cpus                         =      0;
  31 static unsigned int             page_size;
  32 static unsigned int             mmap_pages                      =    128;
  33 static int                      freq                            =   1000;
  34 static int                      output;
  35 static const char               *output_name                    = "perf.data";
  36 static int                      group                           =      0;
  37 static unsigned int             realtime_prio                   =      0;
  38 static int                      raw_samples                     =      0;
  39 static int                      system_wide                     =      0;
  40 static int                      profile_cpu                     =     -1;
  41 static pid_t                    target_pid                      =     -1;
  42 static pid_t                    child_pid                       =     -1;
  43 static int                      inherit                         =      1;
  44 static int                      force                           =      0;
  45 static int                      append_file                     =      0;
  46 static int                      call_graph                      =      0;
  47 static int                      inherit_stat                    =      0;
  48 static int                      no_samples                      =      0;
  49 static int                      sample_address                  =      0;
  50 static int                      multiplex                       =      0;
  51 static int                      multiplex_fd                    =     -1;
  52
  53 static long                     samples                         =      0;
  54 static struct timeval           last_read;
  55 static struct timeval           this_read;
  56
  57 static u64                      bytes_written                   =      0;
  58
  59 static struct pollfd            event_array[MAX_NR_CPUS * MAX_COUNTERS];
  60
  61 static int                      nr_poll                         =      0;
  62 static int                      nr_cpu                          =      0;
  63
  64 static int                      file_new                        =      1;
  65
  66 static struct perf_session      *session;
  67
  68 struct mmap_data {
  69         int                     counter;
  70         void                    *base;
  71         unsigned int            mask;
  72         unsigned int            prev;
  73 };
  74
  75 static struct mmap_data         mmap_array[MAX_NR_CPUS][MAX_COUNTERS];
  76
  77 static unsigned long mmap_read_head(struct mmap_data *md)
  78 {
  79         struct perf_event_mmap_page *pc = md->base;
  80         long head;
  81
  82         head = pc->data_head;
  83         rmb();
  84
  85         return head;
  86 }
  87
  88 static void mmap_write_tail(struct mmap_data *md, unsigned long tail)
  89 {
  90         struct perf_event_mmap_page *pc = md->base;
  91
  92         /*
  93          * ensure all reads are done before we write the tail out.
  94          */
  95         /* mb(); */
  96         pc->data_tail = tail;
  97 }
  98
  99 static void write_output(void *buf, size_t size)
 100 {
 101         while (size) {
 102                 int ret = write(output, buf, size);
 103
 104                 if (ret < 0)
 105                         die("failed to write");
 106
 107                 size -= ret;
 108                 buf += ret;
 109
 110                 bytes_written += ret;
 111         }
 112 }
 113
 114 static void write_event(event_t *buf, size_t size)
 115 {
 116         size_t processed_size = buf->header.size;
 117         event_t *ev = buf;
 118
 119         do {
 120                 /*
 121                 * Add it to the list of DSOs, so that when we finish this
 122                  * record session we can pick the available build-ids.
 123                  */
 124                 if (ev->header.type == PERF_RECORD_MMAP) {
 125                         struct list_head *head = &dsos__user;
 126                         if (ev->header.misc == 1)
 127                                 head = &dsos__kernel;
 128                         __dsos__findnew(head, ev->mmap.filename);
 129                 }
 130
 131                 ev = ((void *)ev) + ev->header.size;
 132                 processed_size += ev->header.size;
 133         } while (processed_size < size);
 134
 135         write_output(buf, size);
 136 }
 137
 138 static int process_synthesized_event(event_t *event,
 139                                      struct perf_session *self __used)
 140 {
 141         write_event(event, event->header.size);
 142         return 0;
 143 }
 144
 145 static void mmap_read(struct mmap_data *md)
 146 {
 147         unsigned int head = mmap_read_head(md);
 148         unsigned int old = md->prev;
 149         unsigned char *data = md->base + page_size;
 150         unsigned long size;
 151         void *buf;
 152         int diff;
 153
 154         gettimeofday(&this_read, NULL);
 155
 156         /*
 157          * If we're further behind than half the buffer, there's a chance
 158          * the writer will bite our tail and mess up the samples under us.
 159          *
 160          * If we somehow ended up ahead of the head, we got messed up.
 161          *
 162          * In either case, truncate and restart at head.
 163          */
 164         diff = head - old;
 165         if (diff < 0) {
 166                 struct timeval iv;
 167                 unsigned long msecs;
 168
 169                 timersub(&this_read, &last_read, &iv);
 170                 msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
 171
 172                 fprintf(stderr, "WARNING: failed to keep up with mmap data."
 173                                 "  Last read %lu msecs ago.\n", msecs);
 174
 175                 /*
 176                  * head points to a known good entry, start there.
 177                  */
 178                 old = head;
 179         }
 180
 181         last_read = this_read;
 182
 183         if (old != head)
 184                 samples++;
 185
 186         size = head - old;
 187
 188         if ((old & md->mask) + size != (head & md->mask)) {
 189                 buf = &data[old & md->mask];
 190                 size = md->mask + 1 - (old & md->mask);
 191                 old += size;
 192
 193                 write_event(buf, size);
 194         }
 195
 196         buf = &data[old & md->mask];
 197         size = head - old;
 198         old += size;
 199
 200         write_event(buf, size);
 201
 202         md->prev = old;
 203         mmap_write_tail(md, old);
 204 }
 205
 206 static volatile int done = 0;
 207 static volatile int signr = -1;
 208
 209 static void sig_handler(int sig)
 210 {
 211         done = 1;
 212         signr = sig;
 213 }
 214
 215 static void sig_atexit(void)
 216 {
 217         if (child_pid != -1)
 218                 kill(child_pid, SIGTERM);
 219
 220         if (signr == -1)
 221                 return;
 222
 223         signal(signr, SIG_DFL);
 224         kill(getpid(), signr);
 225 }
 226
 227 static int group_fd;
 228
 229 static struct perf_header_attr *get_header_attr(struct perf_event_attr *a, int nr)
 230 {
 231         struct perf_header_attr *h_attr;
 232
 233         if (nr < session->header.attrs) {
 234                 h_attr = session->header.attr[nr];
 235         } else {
 236                 h_attr = perf_header_attr__new(a);
 237                 if (h_attr != NULL)
 238                         if (perf_header__add_attr(&session->header, h_attr) < 0) {
 239                                 perf_header_attr__delete(h_attr);
 240                                 h_attr = NULL;
 241                         }
 242         }
 243
 244         return h_attr;
 245 }
 246
 247 static void create_counter(int counter, int cpu, pid_t pid)
 248 {
 249         char *filter = filters[counter];
 250         struct perf_event_attr *attr = attrs + counter;
 251         struct perf_header_attr *h_attr;
 252         int track = !counter; /* only the first counter needs these */
 253         int ret;
 254         struct {
 255                 u64 count;
 256                 u64 time_enabled;
 257                 u64 time_running;
 258                 u64 id;
 259         } read_data;
 260
 261         attr->read_format       = PERF_FORMAT_TOTAL_TIME_ENABLED |
 262                                   PERF_FORMAT_TOTAL_TIME_RUNNING |
 263                                   PERF_FORMAT_ID;
 264
 265         attr->sample_type       |= PERF_SAMPLE_IP | PERF_SAMPLE_TID;
 266
 267         if (freq) {
 268                 attr->sample_type       |= PERF_SAMPLE_PERIOD;
 269                 attr->freq              = 1;
 270                 attr->sample_freq       = freq;
 271         }
 272
 273         if (no_samples)
 274                 attr->sample_freq = 0;
 275
 276         if (inherit_stat)
 277                 attr->inherit_stat = 1;
 278
 279         if (sample_address)
 280                 attr->sample_type       |= PERF_SAMPLE_ADDR;
 281
 282         if (call_graph)
 283                 attr->sample_type       |= PERF_SAMPLE_CALLCHAIN;
 284
 285         if (raw_samples) {
 286                 attr->sample_type       |= PERF_SAMPLE_TIME;
 287                 attr->sample_type       |= PERF_SAMPLE_RAW;
 288                 attr->sample_type       |= PERF_SAMPLE_CPU;
 289         }
 290
 291         attr->mmap              = track;
 292         attr->comm              = track;
 293         attr->inherit           = inherit;
 294         attr->disabled          = 1;
 295
 296 try_again:
 297         fd[nr_cpu][counter] = sys_perf_event_open(attr, pid, cpu, group_fd, 0);
 298
 299         if (fd[nr_cpu][counter] < 0) {
 300                 int err = errno;
 301
 302                 if (err == EPERM || err == EACCES)
 303                         die("Permission error - are you root?\n");
 304                 else if (err ==  ENODEV && profile_cpu != -1)
 305                         die("No such device - did you specify an out-of-range profile CPU?\n");
 306
 307                 /*
 308                  * If it's cycles then fall back to hrtimer
 309                  * based cpu-clock-tick sw counter, which
 310                  * is always available even if no PMU support:
 311                  */
 312                 if (attr->type == PERF_TYPE_HARDWARE
 313                         && attr->config == PERF_COUNT_HW_CPU_CYCLES) {
 314
 315                         if (verbose)
 316                                 warning(" ... trying to fall back to cpu-clock-ticks\n");
 317                         attr->type = PERF_TYPE_SOFTWARE;
 318                         attr->config = PERF_COUNT_SW_CPU_CLOCK;
 319                         goto try_again;
 320                 }
 321                 printf("\n");
 322                 error("perfcounter syscall returned with %d (%s)\n",
 323                         fd[nr_cpu][counter], strerror(err));
 324
 325 #if defined(__i386__) || defined(__x86_64__)
 326                 if (attr->type == PERF_TYPE_HARDWARE && err == EOPNOTSUPP)
 327                         die("No hardware sampling interrupt available. No APIC? If so then you can boot the kernel with the \"lapic\" boot parameter to force-enable it.\n");
 328 #endif
 329
 330                 die("No CONFIG_PERF_EVENTS=y kernel support configured?\n");
 331                 exit(-1);
 332         }
 333
 334         h_attr = get_header_attr(attr, counter);
 335         if (h_attr == NULL)
 336                 die("nomem\n");
 337
 338         if (!file_new) {
 339                 if (memcmp(&h_attr->attr, attr, sizeof(*attr))) {
 340                         fprintf(stderr, "incompatible append\n");
 341                         exit(-1);
 342                 }
 343         }
 344
 345         if (read(fd[nr_cpu][counter], &read_data, sizeof(read_data)) == -1) {
 346                 perror("Unable to read perf file descriptor\n");
 347                 exit(-1);
 348         }
 349
 350         if (perf_header_attr__add_id(h_attr, read_data.id) < 0) {
 351                 pr_warning("Not enough memory to add id\n");
 352                 exit(-1);
 353         }
 354
 355         assert(fd[nr_cpu][counter] >= 0);
 356         fcntl(fd[nr_cpu][counter], F_SETFL, O_NONBLOCK);
 357
 358         /*
 359          * First counter acts as the group leader:
 360          */
 361         if (group && group_fd == -1)
 362                 group_fd = fd[nr_cpu][counter];
 363         if (multiplex && multiplex_fd == -1)
 364                 multiplex_fd = fd[nr_cpu][counter];
 365
 366         if (multiplex && fd[nr_cpu][counter] != multiplex_fd) {
 367
 368                 ret = ioctl(fd[nr_cpu][counter], PERF_EVENT_IOC_SET_OUTPUT, multiplex_fd);
 369                 assert(ret != -1);
 370         } else {
 371                 event_array[nr_poll].fd = fd[nr_cpu][counter];
 372                 event_array[nr_poll].events = POLLIN;
 373                 nr_poll++;
 374
 375                 mmap_array[nr_cpu][counter].counter = counter;
 376                 mmap_array[nr_cpu][counter].prev = 0;
 377                 mmap_array[nr_cpu][counter].mask = mmap_pages*page_size - 1;
 378                 mmap_array[nr_cpu][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
 379                                 PROT_READ|PROT_WRITE, MAP_SHARED, fd[nr_cpu][counter], 0);
 380                 if (mmap_array[nr_cpu][counter].base == MAP_FAILED) {
 381                         error("failed to mmap with %d (%s)\n", errno, strerror(errno));
 382                         exit(-1);
 383                 }
 384         }
 385
 386         if (filter != NULL) {
 387                 ret = ioctl(fd[nr_cpu][counter],
 388                             PERF_EVENT_IOC_SET_FILTER, filter);
 389                 if (ret) {
 390                         error("failed to set filter with %d (%s)\n", errno,
 391                               strerror(errno));
 392                         exit(-1);
 393                 }
 394         }
 395
 396         ioctl(fd[nr_cpu][counter], PERF_EVENT_IOC_ENABLE);
 397 }
 398
 399 static void open_counters(int cpu, pid_t pid)
 400 {
 401         int counter;
 402
 403         group_fd = -1;
 404         for (counter = 0; counter < nr_counters; counter++)
 405                 create_counter(counter, cpu, pid);
 406
 407         nr_cpu++;
 408 }
 409
 410 static void atexit_header(void)
 411 {
 412         session->header.data_size += bytes_written;
 413
 414         perf_header__write(&session->header, output, true);
 415 }
 416
 417 static int __cmd_record(int argc, const char **argv)
 418 {
 419         int i, counter;
 420         struct stat st;
 421         pid_t pid = 0;
 422         int flags;
 423         int err;
 424         unsigned long waking = 0;
 425         int child_ready_pipe[2], go_pipe[2];
 426         const bool forks = target_pid == -1 && argc > 0;
 427         char buf;
 428
 429         page_size = sysconf(_SC_PAGE_SIZE);
 430         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 431         assert(nr_cpus <= MAX_NR_CPUS);
 432         assert(nr_cpus >= 0);
 433
 434         atexit(sig_atexit);
 435         signal(SIGCHLD, sig_handler);
 436         signal(SIGINT, sig_handler);
 437
 438         if (forks && (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) {
 439                 perror("failed to create pipes");
 440                 exit(-1);
 441         }
 442
 443         if (!stat(output_name, &st) && st.st_size) {
 444                 if (!force) {
 445                         if (!append_file) {
 446                                 pr_err("Error, output file %s exists, use -A "
 447                                        "to append or -f to overwrite.\n",
 448                                        output_name);
 449                                 exit(-1);
 450                         }
 451                 } else {
 452                         char oldname[PATH_MAX];
 453                         snprintf(oldname, sizeof(oldname), "%s.old",
 454                                  output_name);
 455                         unlink(oldname);
 456                         rename(output_name, oldname);
 457                 }
 458         } else {
 459                 append_file = 0;
 460         }
 461
 462         flags = O_CREAT|O_RDWR;
 463         if (append_file)
 464                 file_new = 0;
 465         else
 466                 flags |= O_TRUNC;
 467
 468         output = open(output_name, flags, S_IRUSR|S_IWUSR);
 469         if (output < 0) {
 470                 perror("failed to create output file");
 471                 exit(-1);
 472         }
 473
 474         session = perf_session__new(output_name, O_WRONLY, force);
 475         if (session == NULL) {
 476                 pr_err("Not enough memory for reading perf file header\n");
 477                 return -1;
 478         }
 479
 480         if (perf_session__create_kernel_maps(session) < 0) {
 481                 pr_err("Problems creating kernel maps\n");
 482                 return -1;
 483         }
 484
 485         if (!file_new) {
 486                 err = perf_header__read(&session->header, output);
 487                 if (err < 0)
 488                         return err;
 489         }
 490
 491         if (raw_samples) {
 492                 perf_header__set_feat(&session->header, HEADER_TRACE_INFO);
 493         } else {
 494                 for (i = 0; i < nr_counters; i++) {
 495                         if (attrs[i].sample_type & PERF_SAMPLE_RAW) {
 496                                 perf_header__set_feat(&session->header, HEADER_TRACE_INFO);
 497                                 break;
 498                         }
 499                 }
 500         }
 501
 502         atexit(atexit_header);
 503
 504         if (forks) {
 505                 pid = fork();
 506                 if (pid < 0) {
 507                         perror("failed to fork");
 508                         exit(-1);
 509                 }
 510
 511                 if (!pid) {
 512                         close(child_ready_pipe[0]);
 513                         close(go_pipe[1]);
 514                         fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
 515
 516                         /*
 517                          * Do a dummy execvp to get the PLT entry resolved,
 518                          * so we avoid the resolver overhead on the real
 519                          * execvp call.
 520                          */
 521                         execvp("", (char **)argv);
 522
 523                         /*
 524                          * Tell the parent we're ready to go
 525                          */
 526                         close(child_ready_pipe[1]);
 527
 528                         /*
 529                          * Wait until the parent tells us to go.
 530                          */
 531                         if (read(go_pipe[0], &buf, 1) == -1)
 532                                 perror("unable to read pipe");
 533
 534                         execvp(argv[0], (char **)argv);
 535
 536                         perror(argv[0]);
 537                         exit(-1);
 538                 }
 539
 540                 child_pid = pid;
 541
 542                 if (!system_wide)
 543                         target_pid = pid;
 544
 545                 close(child_ready_pipe[1]);
 546                 close(go_pipe[0]);
 547                 /*
 548                  * wait for child to settle
 549                  */
 550                 if (read(child_ready_pipe[0], &buf, 1) == -1) {
 551                         perror("unable to read pipe");
 552                         exit(-1);
 553                 }
 554                 close(child_ready_pipe[0]);
 555         }
 556
 557
 558         if ((!system_wide && !inherit) || profile_cpu != -1) {
 559                 open_counters(profile_cpu, target_pid);
 560         } else {
 561                 for (i = 0; i < nr_cpus; i++)
 562                         open_counters(i, target_pid);
 563         }
 564
 565         if (file_new) {
 566                 err = perf_header__write(&session->header, output, false);
 567                 if (err < 0)
 568                         return err;
 569         }
 570
 571         err = event__synthesize_kernel_mmap(process_synthesized_event,
 572                                             session, "_text");
 573         if (err < 0) {
 574                 pr_err("Couldn't record kernel reference relocation symbol.\n");
 575                 return err;
 576         }
 577
 578         err = event__synthesize_modules(process_synthesized_event, session);
 579         if (err < 0) {
 580                 pr_err("Couldn't record kernel reference relocation symbol.\n");
 581                 return err;
 582         }
 583
 584         if (!system_wide && profile_cpu == -1)
 585                 event__synthesize_thread(pid, process_synthesized_event,
 586                                          session);
 587         else
 588                 event__synthesize_threads(process_synthesized_event, session);
 589
 590         if (realtime_prio) {
 591                 struct sched_param param;
 592
 593                 param.sched_priority = realtime_prio;
 594                 if (sched_setscheduler(0, SCHED_FIFO, &param)) {
 595                         pr_err("Could not set realtime priority.\n");
 596                         exit(-1);
 597                 }
 598         }
 599
 600         /*
 601          * Let the child rip
 602          */
 603         if (forks)
 604                 close(go_pipe[1]);
 605
 606         for (;;) {
 607                 int hits = samples;
 608
 609                 for (i = 0; i < nr_cpu; i++) {
 610                         for (counter = 0; counter < nr_counters; counter++) {
 611                                 if (mmap_array[i][counter].base)
 612                                         mmap_read(&mmap_array[i][counter]);
 613                         }
 614                 }
 615
 616                 if (hits == samples) {
 617                         if (done)
 618                                 break;
 619                         err = poll(event_array, nr_poll, -1);
 620                         waking++;
 621                 }
 622
 623                 if (done) {
 624                         for (i = 0; i < nr_cpu; i++) {
 625                                 for (counter = 0; counter < nr_counters; counter++)
 626                                         ioctl(fd[i][counter], PERF_EVENT_IOC_DISABLE);
 627                         }
 628                 }
 629         }
 630
 631         fprintf(stderr, "[ perf record: Woken up %ld times to write data ]\n", waking);
 632
 633         /*
 634          * Approximate RIP event size: 24 bytes.
 635          */
 636         fprintf(stderr,
 637                 "[ perf record: Captured and wrote %.3f MB %s (~%lld samples) ]\n",
 638                 (double)bytes_written / 1024.0 / 1024.0,
 639                 output_name,
 640                 bytes_written / 24);
 641
 642         return 0;
 643 }
 644
 645 static const char * const record_usage[] = {
 646         "perf record [<options>] [<command>]",
 647         "perf record [<options>] -- <command> [<options>]",
 648         NULL
 649 };
 650
 651 static const struct option options[] = {
 652         OPT_CALLBACK('e', "event", NULL, "event",
 653                      "event selector. use 'perf list' to list available events",
 654                      parse_events),
 655         OPT_CALLBACK(0, "filter", NULL, "filter",
 656                      "event filter", parse_filter),
 657         OPT_INTEGER('p', "pid", &target_pid,
 658                     "record events on existing pid"),
 659         OPT_INTEGER('r', "realtime", &realtime_prio,
 660                     "collect data with this RT SCHED_FIFO priority"),
 661         OPT_BOOLEAN('R', "raw-samples", &raw_samples,
 662                     "collect raw sample records from all opened counters"),
 663         OPT_BOOLEAN('a', "all-cpus", &system_wide,
 664                             "system-wide collection from all CPUs"),
 665         OPT_BOOLEAN('A', "append", &append_file,
 666                             "append to the output file to do incremental profiling"),
 667         OPT_INTEGER('C', "profile_cpu", &profile_cpu,
 668                             "CPU to profile on"),
 669         OPT_BOOLEAN('f', "force", &force,
 670                         "overwrite existing data file"),
 671         OPT_LONG('c', "count", &default_interval,
 672                     "event period to sample"),
 673         OPT_STRING('o', "output", &output_name, "file",
 674                     "output file name"),
 675         OPT_BOOLEAN('i', "inherit", &inherit,
 676                     "child tasks inherit counters"),
 677         OPT_INTEGER('F', "freq", &freq,
 678                     "profile at this frequency"),
 679         OPT_INTEGER('m', "mmap-pages", &mmap_pages,
 680                     "number of mmap data pages"),
 681         OPT_BOOLEAN('g', "call-graph", &call_graph,
 682                     "do call-graph (stack chain/backtrace) recording"),
 683         OPT_BOOLEAN('v', "verbose", &verbose,
 684                     "be more verbose (show counter open errors, etc)"),
 685         OPT_BOOLEAN('s', "stat", &inherit_stat,
 686                     "per thread counts"),
 687         OPT_BOOLEAN('d', "data", &sample_address,
 688                     "Sample addresses"),
 689         OPT_BOOLEAN('n', "no-samples", &no_samples,
 690                     "don't sample"),
 691         OPT_BOOLEAN('M', "multiplex", &multiplex,
 692                     "multiplex counter output in a single channel"),
 693         OPT_END()
 694 };
 695
 696 int cmd_record(int argc, const char **argv, const char *prefix __used)
 697 {
 698         int counter;
 699
 700         argc = parse_options(argc, argv, options, record_usage,
 701                             PARSE_OPT_STOP_AT_NON_OPTION);
 702         if (!argc && target_pid == -1 && !system_wide && profile_cpu == -1)
 703                 usage_with_options(record_usage, options);
 704
 705         symbol__init();
 706
 707         if (!nr_counters) {
 708                 nr_counters     = 1;
 709                 attrs[0].type   = PERF_TYPE_HARDWARE;
 710                 attrs[0].config = PERF_COUNT_HW_CPU_CYCLES;
 711         }
 712
 713         /*
 714          * User specified count overrides default frequency.
 715          */
 716         if (default_interval)
 717                 freq = 0;
 718         else if (freq) {
 719                 default_interval = freq;
 720         } else {
 721                 fprintf(stderr, "frequency and count are zero, aborting\n");
 722                 exit(EXIT_FAILURE);
 723         }
 724
 725         for (counter = 0; counter < nr_counters; counter++) {
 726                 if (attrs[counter].sample_period)
 727                         continue;
 728
 729                 attrs[counter].sample_period = default_interval;
 730         }
 731
 732         return __cmd_record(argc, argv);
 733 }