tools/perf/builtin-top.c

   1 /*
   2  * builtin-top.c
   3  *
   4  * Builtin top command: Display a continuously updated profile of
   5  * any workload, CPU or specific PID.
   6  *
   7  * Copyright (C) 2008, Red Hat Inc, Ingo Molnar <mingo@redhat.com>
   8  *
   9  * Improvements and fixes by:
  10  *
  11  *   Arjan van de Ven <arjan@linux.intel.com>
  12  *   Yanmin Zhang <yanmin.zhang@intel.com>
  13  *   Wu Fengguang <fengguang.wu@intel.com>
  14  *   Mike Galbraith <efault@gmx.de>
  15  *   Paul Mackerras <paulus@samba.org>
  16  *
  17  * Released under the GPL v2. (and only v2, not any later version)
  18  */
  19 #include "builtin.h"
  20
  21 #include "perf.h"
  22
  23 #include "util/symbol.h"
  24 #include "util/color.h"
  25 #include "util/util.h"
  26 #include <linux/rbtree.h>
  27 #include "util/parse-options.h"
  28 #include "util/parse-events.h"
  29
  30 #include <assert.h>
  31 #include <fcntl.h>
  32
  33 #include <stdio.h>
  34
  35 #include <errno.h>
  36 #include <time.h>
  37 #include <sched.h>
  38 #include <pthread.h>
  39
  40 #include <sys/syscall.h>
  41 #include <sys/ioctl.h>
  42 #include <sys/poll.h>
  43 #include <sys/prctl.h>
  44 #include <sys/wait.h>
  45 #include <sys/uio.h>
  46 #include <sys/mman.h>
  47
  48 #include <linux/unistd.h>
  49 #include <linux/types.h>
  50
  51 static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
  52
  53 static int                      system_wide                     =  0;
  54
  55 static int                      default_interval                = 100000;
  56
  57 static u64                      count_filter                    =  5;
  58 static int                      print_entries                   = 15;
  59
  60 static int                      target_pid                      = -1;
  61 static int                      inherit                         =  0;
  62 static int                      profile_cpu                     = -1;
  63 static int                      nr_cpus                         =  0;
  64 static unsigned int             realtime_prio                   =  0;
  65 static int                      group                           =  0;
  66 static unsigned int             page_size;
  67 static unsigned int             mmap_pages                      = 16;
  68 static int                      freq                            =  0;
  69 static int                      verbose                         =  0;
  70 static char                     *vmlinux                        =  NULL;
  71
  72 static char                     *sym_filter;
  73 static unsigned long            filter_start;
  74 static unsigned long            filter_end;
  75
  76 static int                      delay_secs                      =  2;
  77 static int                      zero;
  78 static int                      dump_symtab;
  79
  80 /*
  81  * Symbols
  82  */
  83
  84 static u64                      min_ip;
  85 static u64                      max_ip = -1ll;
  86
  87 struct sym_entry {
  88         struct rb_node          rb_node;
  89         struct list_head        node;
  90         unsigned long           count[MAX_COUNTERS];
  91         unsigned long           snap_count;
  92         double                  weight;
  93         int                     skip;
  94 };
  95
  96 struct sym_entry                *sym_filter_entry;
  97
  98 struct dso                      *kernel_dso;
  99
 100 /*
 101  * Symbols will be added here in record_ip and will get out
 102  * after decayed.
 103  */
 104 static LIST_HEAD(active_symbols);
 105 static pthread_mutex_t active_symbols_lock = PTHREAD_MUTEX_INITIALIZER;
 106
 107 /*
 108  * Ordering weight: count-1 * count-2 * ... / count-n
 109  */
 110 static double sym_weight(const struct sym_entry *sym)
 111 {
 112         double weight = sym->snap_count;
 113         int counter;
 114
 115         for (counter = 1; counter < nr_counters-1; counter++)
 116                 weight *= sym->count[counter];
 117
 118         weight /= (sym->count[counter] + 1);
 119
 120         return weight;
 121 }
 122
 123 static long                     samples;
 124 static long                     userspace_samples;
 125 static const char               CONSOLE_CLEAR[] = "\e[H\e[2J";
 126
 127 static void __list_insert_active_sym(struct sym_entry *syme)
 128 {
 129         list_add(&syme->node, &active_symbols);
 130 }
 131
 132 static void list_remove_active_sym(struct sym_entry *syme)
 133 {
 134         pthread_mutex_lock(&active_symbols_lock);
 135         list_del_init(&syme->node);
 136         pthread_mutex_unlock(&active_symbols_lock);
 137 }
 138
 139 static void rb_insert_active_sym(struct rb_root *tree, struct sym_entry *se)
 140 {
 141         struct rb_node **p = &tree->rb_node;
 142         struct rb_node *parent = NULL;
 143         struct sym_entry *iter;
 144
 145         while (*p != NULL) {
 146                 parent = *p;
 147                 iter = rb_entry(parent, struct sym_entry, rb_node);
 148
 149                 if (se->weight > iter->weight)
 150                         p = &(*p)->rb_left;
 151                 else
 152                         p = &(*p)->rb_right;
 153         }
 154
 155         rb_link_node(&se->rb_node, parent, p);
 156         rb_insert_color(&se->rb_node, tree);
 157 }
 158
 159 static void print_sym_table(void)
 160 {
 161         int printed = 0, j;
 162         int counter;
 163         float samples_per_sec = samples/delay_secs;
 164         float ksamples_per_sec = (samples-userspace_samples)/delay_secs;
 165         float sum_ksamples = 0.0;
 166         struct sym_entry *syme, *n;
 167         struct rb_root tmp = RB_ROOT;
 168         struct rb_node *nd;
 169
 170         samples = userspace_samples = 0;
 171
 172         /* Sort the active symbols */
 173         pthread_mutex_lock(&active_symbols_lock);
 174         syme = list_entry(active_symbols.next, struct sym_entry, node);
 175         pthread_mutex_unlock(&active_symbols_lock);
 176
 177         list_for_each_entry_safe_from(syme, n, &active_symbols, node) {
 178                 syme->snap_count = syme->count[0];
 179                 if (syme->snap_count != 0) {
 180                         syme->weight = sym_weight(syme);
 181                         rb_insert_active_sym(&tmp, syme);
 182                         sum_ksamples += syme->snap_count;
 183
 184                         for (j = 0; j < nr_counters; j++)
 185                                 syme->count[j] = zero ? 0 : syme->count[j] * 7 / 8;
 186                 } else
 187                         list_remove_active_sym(syme);
 188         }
 189
 190         puts(CONSOLE_CLEAR);
 191
 192         printf(
 193 "------------------------------------------------------------------------------\n");
 194         printf( "   PerfTop:%8.0f irqs/sec  kernel:%4.1f%% [",
 195                 samples_per_sec,
 196                 100.0 - (100.0*((samples_per_sec-ksamples_per_sec)/samples_per_sec)));
 197
 198         if (nr_counters == 1) {
 199                 printf("%Ld", (u64)attrs[0].sample_period);
 200                 if (freq)
 201                         printf("Hz ");
 202                 else
 203                         printf(" ");
 204         }
 205
 206         for (counter = 0; counter < nr_counters; counter++) {
 207                 if (counter)
 208                         printf("/");
 209
 210                 printf("%s", event_name(counter));
 211         }
 212
 213         printf( "], ");
 214
 215         if (target_pid != -1)
 216                 printf(" (target_pid: %d", target_pid);
 217         else
 218                 printf(" (all");
 219
 220         if (profile_cpu != -1)
 221                 printf(", cpu: %d)\n", profile_cpu);
 222         else {
 223                 if (target_pid != -1)
 224                         printf(")\n");
 225                 else
 226                         printf(", %d CPUs)\n", nr_cpus);
 227         }
 228
 229         printf("------------------------------------------------------------------------------\n\n");
 230
 231         if (nr_counters == 1)
 232                 printf("             samples    pcnt");
 233         else
 234                 printf("  weight     samples    pcnt");
 235
 236         printf("         RIP          kernel function\n"
 237                        "  ______     _______   _____   ________________   _______________\n\n"
 238         );
 239
 240         for (nd = rb_first(&tmp); nd; nd = rb_next(nd)) {
 241                 struct sym_entry *syme = rb_entry(nd, struct sym_entry, rb_node);
 242                 struct symbol *sym = (struct symbol *)(syme + 1);
 243                 double pcnt;
 244
 245                 if (++printed > print_entries || syme->snap_count < count_filter)
 246                         continue;
 247
 248                 pcnt = 100.0 - (100.0 * ((sum_ksamples - syme->snap_count) /
 249                                          sum_ksamples));
 250
 251                 if (nr_counters == 1)
 252                         printf("%20.2f - ", syme->weight);
 253                 else
 254                         printf("%9.1f %10ld - ", syme->weight, syme->snap_count);
 255
 256                 percent_color_fprintf(stdout, "%4.1f%%", pcnt);
 257                 printf(" - %016llx : %s", sym->start, sym->name);
 258                 if (sym->module)
 259                         printf("\t[%s]", sym->module->name);
 260                 printf("\n");
 261         }
 262 }
 263
 264 static void *display_thread(void *arg __used)
 265 {
 266         struct pollfd stdin_poll = { .fd = 0, .events = POLLIN };
 267         int delay_msecs = delay_secs * 1000;
 268
 269         printf("PerfTop refresh period: %d seconds\n", delay_secs);
 270
 271         do {
 272                 print_sym_table();
 273         } while (!poll(&stdin_poll, 1, delay_msecs) == 1);
 274
 275         printf("key pressed - exiting.\n");
 276         exit(0);
 277
 278         return NULL;
 279 }
 280
 281 /* Tag samples to be skipped. */
 282 static const char *skip_symbols[] = {
 283         "default_idle",
 284         "cpu_idle",
 285         "enter_idle",
 286         "exit_idle",
 287         "mwait_idle",
 288         "mwait_idle_with_hints",
 289         "ppc64_runlatch_off",
 290         "pseries_dedicated_idle_sleep",
 291         NULL
 292 };
 293
 294 static int symbol_filter(struct dso *self, struct symbol *sym)
 295 {
 296         static int filter_match;
 297         struct sym_entry *syme;
 298         const char *name = sym->name;
 299         int i;
 300
 301         /*
 302          * ppc64 uses function descriptors and appends a '.' to the
 303          * start of every instruction address. Remove it.
 304          */
 305         if (name[0] == '.')
 306                 name++;
 307
 308         if (!strcmp(name, "_text") ||
 309             !strcmp(name, "_etext") ||
 310             !strcmp(name, "_sinittext") ||
 311             !strncmp("init_module", name, 11) ||
 312             !strncmp("cleanup_module", name, 14) ||
 313             strstr(name, "_text_start") ||
 314             strstr(name, "_text_end"))
 315                 return 1;
 316
 317         syme = dso__sym_priv(self, sym);
 318         for (i = 0; skip_symbols[i]; i++) {
 319                 if (!strcmp(skip_symbols[i], name)) {
 320                         syme->skip = 1;
 321                         break;
 322                 }
 323         }
 324
 325         if (filter_match == 1) {
 326                 filter_end = sym->start;
 327                 filter_match = -1;
 328                 if (filter_end - filter_start > 10000) {
 329                         fprintf(stderr,
 330                                 "hm, too large filter symbol <%s> - skipping.\n",
 331                                 sym_filter);
 332                         fprintf(stderr, "symbol filter start: %016lx\n",
 333                                 filter_start);
 334                         fprintf(stderr, "                end: %016lx\n",
 335                                 filter_end);
 336                         filter_end = filter_start = 0;
 337                         sym_filter = NULL;
 338                         sleep(1);
 339                 }
 340         }
 341
 342         if (filter_match == 0 && sym_filter && !strcmp(name, sym_filter)) {
 343                 filter_match = 1;
 344                 filter_start = sym->start;
 345         }
 346
 347
 348         return 0;
 349 }
 350
 351 static int parse_symbols(void)
 352 {
 353         struct rb_node *node;
 354         struct symbol  *sym;
 355         int modules = vmlinux ? 1 : 0;
 356
 357         kernel_dso = dso__new("[kernel]", sizeof(struct sym_entry));
 358         if (kernel_dso == NULL)
 359                 return -1;
 360
 361         if (dso__load_kernel(kernel_dso, vmlinux, symbol_filter, verbose, modules) <= 0)
 362                 goto out_delete_dso;
 363
 364         node = rb_first(&kernel_dso->syms);
 365         sym = rb_entry(node, struct symbol, rb_node);
 366         min_ip = sym->start;
 367
 368         node = rb_last(&kernel_dso->syms);
 369         sym = rb_entry(node, struct symbol, rb_node);
 370         max_ip = sym->end;
 371
 372         if (dump_symtab)
 373                 dso__fprintf(kernel_dso, stderr);
 374
 375         return 0;
 376
 377 out_delete_dso:
 378         dso__delete(kernel_dso);
 379         kernel_dso = NULL;
 380         return -1;
 381 }
 382
 383 #define TRACE_COUNT     3
 384
 385 /*
 386  * Binary search in the histogram table and record the hit:
 387  */
 388 static void record_ip(u64 ip, int counter)
 389 {
 390         struct symbol *sym = dso__find_symbol(kernel_dso, ip);
 391
 392         if (sym != NULL) {
 393                 struct sym_entry *syme = dso__sym_priv(kernel_dso, sym);
 394
 395                 if (!syme->skip) {
 396                         syme->count[counter]++;
 397                         pthread_mutex_lock(&active_symbols_lock);
 398                         if (list_empty(&syme->node) || !syme->node.next)
 399                                 __list_insert_active_sym(syme);
 400                         pthread_mutex_unlock(&active_symbols_lock);
 401                         return;
 402                 }
 403         }
 404
 405         samples--;
 406 }
 407
 408 static void process_event(u64 ip, int counter, int user)
 409 {
 410         samples++;
 411
 412         if (user) {
 413                 userspace_samples++;
 414                 return;
 415         }
 416
 417         record_ip(ip, counter);
 418 }
 419
 420 struct mmap_data {
 421         int                     counter;
 422         void                    *base;
 423         int                     mask;
 424         unsigned int            prev;
 425 };
 426
 427 static unsigned int mmap_read_head(struct mmap_data *md)
 428 {
 429         struct perf_counter_mmap_page *pc = md->base;
 430         int head;
 431
 432         head = pc->data_head;
 433         rmb();
 434
 435         return head;
 436 }
 437
 438 struct timeval last_read, this_read;
 439
 440 static void mmap_read_counter(struct mmap_data *md)
 441 {
 442         unsigned int head = mmap_read_head(md);
 443         unsigned int old = md->prev;
 444         unsigned char *data = md->base + page_size;
 445         int diff;
 446
 447         gettimeofday(&this_read, NULL);
 448
 449         /*
 450          * If we're further behind than half the buffer, there's a chance
 451          * the writer will bite our tail and mess up the samples under us.
 452          *
 453          * If we somehow ended up ahead of the head, we got messed up.
 454          *
 455          * In either case, truncate and restart at head.
 456          */
 457         diff = head - old;
 458         if (diff > md->mask / 2 || diff < 0) {
 459                 struct timeval iv;
 460                 unsigned long msecs;
 461
 462                 timersub(&this_read, &last_read, &iv);
 463                 msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
 464
 465                 fprintf(stderr, "WARNING: failed to keep up with mmap data."
 466                                 "  Last read %lu msecs ago.\n", msecs);
 467
 468                 /*
 469                  * head points to a known good entry, start there.
 470                  */
 471                 old = head;
 472         }
 473
 474         last_read = this_read;
 475
 476         for (; old != head;) {
 477                 struct ip_event {
 478                         struct perf_event_header header;
 479                         u64 ip;
 480                         u32 pid, target_pid;
 481                 };
 482                 struct mmap_event {
 483                         struct perf_event_header header;
 484                         u32 pid, target_pid;
 485                         u64 start;
 486                         u64 len;
 487                         u64 pgoff;
 488                         char filename[PATH_MAX];
 489                 };
 490
 491                 typedef union event_union {
 492                         struct perf_event_header header;
 493                         struct ip_event ip;
 494                         struct mmap_event mmap;
 495                 } event_t;
 496
 497                 event_t *event = (event_t *)&data[old & md->mask];
 498
 499                 event_t event_copy;
 500
 501                 size_t size = event->header.size;
 502
 503                 /*
 504                  * Event straddles the mmap boundary -- header should always
 505                  * be inside due to u64 alignment of output.
 506                  */
 507                 if ((old & md->mask) + size != ((old + size) & md->mask)) {
 508                         unsigned int offset = old;
 509                         unsigned int len = min(sizeof(*event), size), cpy;
 510                         void *dst = &event_copy;
 511
 512                         do {
 513                                 cpy = min(md->mask + 1 - (offset & md->mask), len);
 514                                 memcpy(dst, &data[offset & md->mask], cpy);
 515                                 offset += cpy;
 516                                 dst += cpy;
 517                                 len -= cpy;
 518                         } while (len);
 519
 520                         event = &event_copy;
 521                 }
 522
 523                 old += size;
 524
 525                 if (event->header.type == PERF_EVENT_SAMPLE) {
 526                         int user =
 527         (event->header.misc & PERF_EVENT_MISC_CPUMODE_MASK) == PERF_EVENT_MISC_USER;
 528                         process_event(event->ip.ip, md->counter, user);
 529                 }
 530         }
 531
 532         md->prev = old;
 533 }
 534
 535 static struct pollfd event_array[MAX_NR_CPUS * MAX_COUNTERS];
 536 static struct mmap_data mmap_array[MAX_NR_CPUS][MAX_COUNTERS];
 537
 538 static void mmap_read(void)
 539 {
 540         int i, counter;
 541
 542         for (i = 0; i < nr_cpus; i++) {
 543                 for (counter = 0; counter < nr_counters; counter++)
 544                         mmap_read_counter(&mmap_array[i][counter]);
 545         }
 546 }
 547
 548 int nr_poll;
 549 int group_fd;
 550
 551 static void start_counter(int i, int counter)
 552 {
 553         struct perf_counter_attr *attr;
 554         int cpu;
 555
 556         cpu = profile_cpu;
 557         if (target_pid == -1 && profile_cpu == -1)
 558                 cpu = i;
 559
 560         attr = attrs + counter;
 561
 562         attr->sample_type       = PERF_SAMPLE_IP | PERF_SAMPLE_TID;
 563         attr->freq              = freq;
 564         attr->inherit           = (cpu < 0) && inherit;
 565
 566 try_again:
 567         fd[i][counter] = sys_perf_counter_open(attr, target_pid, cpu, group_fd, 0);
 568
 569         if (fd[i][counter] < 0) {
 570                 int err = errno;
 571
 572                 if (err == EPERM)
 573                         die("No permission - are you root?\n");
 574                 /*
 575                  * If it's cycles then fall back to hrtimer
 576                  * based cpu-clock-tick sw counter, which
 577                  * is always available even if no PMU support:
 578                  */
 579                 if (attr->type == PERF_TYPE_HARDWARE
 580                         && attr->config == PERF_COUNT_HW_CPU_CYCLES) {
 581
 582                         if (verbose)
 583                                 warning(" ... trying to fall back to cpu-clock-ticks\n");
 584
 585                         attr->type = PERF_TYPE_SOFTWARE;
 586                         attr->config = PERF_COUNT_SW_CPU_CLOCK;
 587                         goto try_again;
 588                 }
 589                 printf("\n");
 590                 error("perfcounter syscall returned with %d (%s)\n",
 591                         fd[i][counter], strerror(err));
 592                 die("No CONFIG_PERF_COUNTERS=y kernel support configured?\n");
 593                 exit(-1);
 594         }
 595         assert(fd[i][counter] >= 0);
 596         fcntl(fd[i][counter], F_SETFL, O_NONBLOCK);
 597
 598         /*
 599          * First counter acts as the group leader:
 600          */
 601         if (group && group_fd == -1)
 602                 group_fd = fd[i][counter];
 603
 604         event_array[nr_poll].fd = fd[i][counter];
 605         event_array[nr_poll].events = POLLIN;
 606         nr_poll++;
 607
 608         mmap_array[i][counter].counter = counter;
 609         mmap_array[i][counter].prev = 0;
 610         mmap_array[i][counter].mask = mmap_pages*page_size - 1;
 611         mmap_array[i][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
 612                         PROT_READ, MAP_SHARED, fd[i][counter], 0);
 613         if (mmap_array[i][counter].base == MAP_FAILED)
 614                 die("failed to mmap with %d (%s)\n", errno, strerror(errno));
 615 }
 616
 617 static int __cmd_top(void)
 618 {
 619         pthread_t thread;
 620         int i, counter;
 621         int ret;
 622
 623         for (i = 0; i < nr_cpus; i++) {
 624                 group_fd = -1;
 625                 for (counter = 0; counter < nr_counters; counter++)
 626                         start_counter(i, counter);
 627         }
 628
 629         /* Wait for a minimal set of events before starting the snapshot */
 630         poll(event_array, nr_poll, 100);
 631
 632         mmap_read();
 633
 634         if (pthread_create(&thread, NULL, display_thread, NULL)) {
 635                 printf("Could not create display thread.\n");
 636                 exit(-1);
 637         }
 638
 639         if (realtime_prio) {
 640                 struct sched_param param;
 641
 642                 param.sched_priority = realtime_prio;
 643                 if (sched_setscheduler(0, SCHED_FIFO, &param)) {
 644                         printf("Could not set realtime priority.\n");
 645                         exit(-1);
 646                 }
 647         }
 648
 649         while (1) {
 650                 int hits = samples;
 651
 652                 mmap_read();
 653
 654                 if (hits == samples)
 655                         ret = poll(event_array, nr_poll, 100);
 656         }
 657
 658         return 0;
 659 }
 660
 661 static const char * const top_usage[] = {
 662         "perf top [<options>]",
 663         NULL
 664 };
 665
 666 static const struct option options[] = {
 667         OPT_CALLBACK('e', "event", NULL, "event",
 668                      "event selector. use 'perf list' to list available events",
 669                      parse_events),
 670         OPT_INTEGER('c', "count", &default_interval,
 671                     "event period to sample"),
 672         OPT_INTEGER('p', "pid", &target_pid,
 673                     "profile events on existing pid"),
 674         OPT_BOOLEAN('a', "all-cpus", &system_wide,
 675                             "system-wide collection from all CPUs"),
 676         OPT_INTEGER('C', "CPU", &profile_cpu,
 677                     "CPU to profile on"),
 678         OPT_STRING('k', "vmlinux", &vmlinux, "file", "vmlinux pathname"),
 679         OPT_INTEGER('m', "mmap-pages", &mmap_pages,
 680                     "number of mmap data pages"),
 681         OPT_INTEGER('r', "realtime", &realtime_prio,
 682                     "collect data with this RT SCHED_FIFO priority"),
 683         OPT_INTEGER('d', "delay", &delay_secs,
 684                     "number of seconds to delay between refreshes"),
 685         OPT_BOOLEAN('D', "dump-symtab", &dump_symtab,
 686                             "dump the symbol table used for profiling"),
 687         OPT_INTEGER('f', "count-filter", &count_filter,
 688                     "only display functions with more events than this"),
 689         OPT_BOOLEAN('g', "group", &group,
 690                             "put the counters into a counter group"),
 691         OPT_BOOLEAN('i', "inherit", &inherit,
 692                     "child tasks inherit counters"),
 693         OPT_STRING('s', "sym-filter", &sym_filter, "pattern",
 694                     "only display symbols matchig this pattern"),
 695         OPT_BOOLEAN('z', "zero", &zero,
 696                     "zero history across updates"),
 697         OPT_INTEGER('F', "freq", &freq,
 698                     "profile at this frequency"),
 699         OPT_INTEGER('E', "entries", &print_entries,
 700                     "display this many functions"),
 701         OPT_BOOLEAN('v', "verbose", &verbose,
 702                     "be more verbose (show counter open errors, etc)"),
 703         OPT_END()
 704 };
 705
 706 int cmd_top(int argc, const char **argv, const char *prefix __used)
 707 {
 708         int counter;
 709
 710         symbol__init();
 711
 712         page_size = sysconf(_SC_PAGE_SIZE);
 713
 714         argc = parse_options(argc, argv, options, top_usage, 0);
 715         if (argc)
 716                 usage_with_options(top_usage, options);
 717
 718         if (freq) {
 719                 default_interval = freq;
 720                 freq = 1;
 721         }
 722
 723         /* CPU and PID are mutually exclusive */
 724         if (target_pid != -1 && profile_cpu != -1) {
 725                 printf("WARNING: PID switch overriding CPU\n");
 726                 sleep(1);
 727                 profile_cpu = -1;
 728         }
 729
 730         if (!nr_counters)
 731                 nr_counters = 1;
 732
 733         if (delay_secs < 1)
 734                 delay_secs = 1;
 735
 736         parse_symbols();
 737
 738         /*
 739          * Fill in the ones not specifically initialized via -c:
 740          */
 741         for (counter = 0; counter < nr_counters; counter++) {
 742                 if (attrs[counter].sample_period)
 743                         continue;
 744
 745                 attrs[counter].sample_period = default_interval;
 746         }
 747
 748         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 749         assert(nr_cpus <= MAX_NR_CPUS);
 750         assert(nr_cpus >= 0);
 751
 752         if (target_pid != -1 || profile_cpu != -1)
 753                 nr_cpus = 1;
 754
 755         return __cmd_top();
 756 }