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         "ppc64_runlatch_off",
 289         "pseries_dedicated_idle_sleep",
 290         NULL
 291 };
 292
 293 static int symbol_filter(struct dso *self, struct symbol *sym)
 294 {
 295         static int filter_match;
 296         struct sym_entry *syme;
 297         const char *name = sym->name;
 298         int i;
 299
 300         /*
 301          * ppc64 uses function descriptors and appends a '.' to the
 302          * start of every instruction address. Remove it.
 303          */
 304         if (name[0] == '.')
 305                 name++;
 306
 307         if (!strcmp(name, "_text") ||
 308             !strcmp(name, "_etext") ||
 309             !strcmp(name, "_sinittext") ||
 310             !strncmp("init_module", name, 11) ||
 311             !strncmp("cleanup_module", name, 14) ||
 312             strstr(name, "_text_start") ||
 313             strstr(name, "_text_end"))
 314                 return 1;
 315
 316         syme = dso__sym_priv(self, sym);
 317         for (i = 0; skip_symbols[i]; i++) {
 318                 if (!strcmp(skip_symbols[i], name)) {
 319                         syme->skip = 1;
 320                         break;
 321                 }
 322         }
 323
 324         if (filter_match == 1) {
 325                 filter_end = sym->start;
 326                 filter_match = -1;
 327                 if (filter_end - filter_start > 10000) {
 328                         fprintf(stderr,
 329                                 "hm, too large filter symbol <%s> - skipping.\n",
 330                                 sym_filter);
 331                         fprintf(stderr, "symbol filter start: %016lx\n",
 332                                 filter_start);
 333                         fprintf(stderr, "                end: %016lx\n",
 334                                 filter_end);
 335                         filter_end = filter_start = 0;
 336                         sym_filter = NULL;
 337                         sleep(1);
 338                 }
 339         }
 340
 341         if (filter_match == 0 && sym_filter && !strcmp(name, sym_filter)) {
 342                 filter_match = 1;
 343                 filter_start = sym->start;
 344         }
 345
 346
 347         return 0;
 348 }
 349
 350 static int parse_symbols(void)
 351 {
 352         struct rb_node *node;
 353         struct symbol  *sym;
 354         int modules = vmlinux ? 1 : 0;
 355
 356         kernel_dso = dso__new("[kernel]", sizeof(struct sym_entry));
 357         if (kernel_dso == NULL)
 358                 return -1;
 359
 360         if (dso__load_kernel(kernel_dso, vmlinux, symbol_filter, verbose, modules) <= 0)
 361                 goto out_delete_dso;
 362
 363         node = rb_first(&kernel_dso->syms);
 364         sym = rb_entry(node, struct symbol, rb_node);
 365         min_ip = sym->start;
 366
 367         node = rb_last(&kernel_dso->syms);
 368         sym = rb_entry(node, struct symbol, rb_node);
 369         max_ip = sym->end;
 370
 371         if (dump_symtab)
 372                 dso__fprintf(kernel_dso, stderr);
 373
 374         return 0;
 375
 376 out_delete_dso:
 377         dso__delete(kernel_dso);
 378         kernel_dso = NULL;
 379         return -1;
 380 }
 381
 382 #define TRACE_COUNT     3
 383
 384 /*
 385  * Binary search in the histogram table and record the hit:
 386  */
 387 static void record_ip(u64 ip, int counter)
 388 {
 389         struct symbol *sym = dso__find_symbol(kernel_dso, ip);
 390
 391         if (sym != NULL) {
 392                 struct sym_entry *syme = dso__sym_priv(kernel_dso, sym);
 393
 394                 if (!syme->skip) {
 395                         syme->count[counter]++;
 396                         pthread_mutex_lock(&active_symbols_lock);
 397                         if (list_empty(&syme->node) || !syme->node.next)
 398                                 __list_insert_active_sym(syme);
 399                         pthread_mutex_unlock(&active_symbols_lock);
 400                         return;
 401                 }
 402         }
 403
 404         samples--;
 405 }
 406
 407 static void process_event(u64 ip, int counter, int user)
 408 {
 409         samples++;
 410
 411         if (user) {
 412                 userspace_samples++;
 413                 return;
 414         }
 415
 416         record_ip(ip, counter);
 417 }
 418
 419 struct mmap_data {
 420         int                     counter;
 421         void                    *base;
 422         int                     mask;
 423         unsigned int            prev;
 424 };
 425
 426 static unsigned int mmap_read_head(struct mmap_data *md)
 427 {
 428         struct perf_counter_mmap_page *pc = md->base;
 429         int head;
 430
 431         head = pc->data_head;
 432         rmb();
 433
 434         return head;
 435 }
 436
 437 struct timeval last_read, this_read;
 438
 439 static void mmap_read_counter(struct mmap_data *md)
 440 {
 441         unsigned int head = mmap_read_head(md);
 442         unsigned int old = md->prev;
 443         unsigned char *data = md->base + page_size;
 444         int diff;
 445
 446         gettimeofday(&this_read, NULL);
 447
 448         /*
 449          * If we're further behind than half the buffer, there's a chance
 450          * the writer will bite our tail and mess up the samples under us.
 451          *
 452          * If we somehow ended up ahead of the head, we got messed up.
 453          *
 454          * In either case, truncate and restart at head.
 455          */
 456         diff = head - old;
 457         if (diff > md->mask / 2 || diff < 0) {
 458                 struct timeval iv;
 459                 unsigned long msecs;
 460
 461                 timersub(&this_read, &last_read, &iv);
 462                 msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
 463
 464                 fprintf(stderr, "WARNING: failed to keep up with mmap data."
 465                                 "  Last read %lu msecs ago.\n", msecs);
 466
 467                 /*
 468                  * head points to a known good entry, start there.
 469                  */
 470                 old = head;
 471         }
 472
 473         last_read = this_read;
 474
 475         for (; old != head;) {
 476                 struct ip_event {
 477                         struct perf_event_header header;
 478                         u64 ip;
 479                         u32 pid, target_pid;
 480                 };
 481                 struct mmap_event {
 482                         struct perf_event_header header;
 483                         u32 pid, target_pid;
 484                         u64 start;
 485                         u64 len;
 486                         u64 pgoff;
 487                         char filename[PATH_MAX];
 488                 };
 489
 490                 typedef union event_union {
 491                         struct perf_event_header header;
 492                         struct ip_event ip;
 493                         struct mmap_event mmap;
 494                 } event_t;
 495
 496                 event_t *event = (event_t *)&data[old & md->mask];
 497
 498                 event_t event_copy;
 499
 500                 size_t size = event->header.size;
 501
 502                 /*
 503                  * Event straddles the mmap boundary -- header should always
 504                  * be inside due to u64 alignment of output.
 505                  */
 506                 if ((old & md->mask) + size != ((old + size) & md->mask)) {
 507                         unsigned int offset = old;
 508                         unsigned int len = min(sizeof(*event), size), cpy;
 509                         void *dst = &event_copy;
 510
 511                         do {
 512                                 cpy = min(md->mask + 1 - (offset & md->mask), len);
 513                                 memcpy(dst, &data[offset & md->mask], cpy);
 514                                 offset += cpy;
 515                                 dst += cpy;
 516                                 len -= cpy;
 517                         } while (len);
 518
 519                         event = &event_copy;
 520                 }
 521
 522                 old += size;
 523
 524                 if (event->header.type == PERF_EVENT_SAMPLE) {
 525                         int user =
 526         (event->header.misc & PERF_EVENT_MISC_CPUMODE_MASK) == PERF_EVENT_MISC_USER;
 527                         process_event(event->ip.ip, md->counter, user);
 528                 }
 529         }
 530
 531         md->prev = old;
 532 }
 533
 534 static struct pollfd event_array[MAX_NR_CPUS * MAX_COUNTERS];
 535 static struct mmap_data mmap_array[MAX_NR_CPUS][MAX_COUNTERS];
 536
 537 static void mmap_read(void)
 538 {
 539         int i, counter;
 540
 541         for (i = 0; i < nr_cpus; i++) {
 542                 for (counter = 0; counter < nr_counters; counter++)
 543                         mmap_read_counter(&mmap_array[i][counter]);
 544         }
 545 }
 546
 547 int nr_poll;
 548 int group_fd;
 549
 550 static void start_counter(int i, int counter)
 551 {
 552         struct perf_counter_attr *attr;
 553         int cpu;
 554
 555         cpu = profile_cpu;
 556         if (target_pid == -1 && profile_cpu == -1)
 557                 cpu = i;
 558
 559         attr = attrs + counter;
 560
 561         attr->sample_type       = PERF_SAMPLE_IP | PERF_SAMPLE_TID;
 562         attr->freq              = freq;
 563         attr->inherit           = (cpu < 0) && inherit;
 564
 565 try_again:
 566         fd[i][counter] = sys_perf_counter_open(attr, target_pid, cpu, group_fd, 0);
 567
 568         if (fd[i][counter] < 0) {
 569                 int err = errno;
 570
 571                 if (err == EPERM)
 572                         die("No permission - are you root?\n");
 573                 /*
 574                  * If it's cycles then fall back to hrtimer
 575                  * based cpu-clock-tick sw counter, which
 576                  * is always available even if no PMU support:
 577                  */
 578                 if (attr->type == PERF_TYPE_HARDWARE
 579                         && attr->config == PERF_COUNT_HW_CPU_CYCLES) {
 580
 581                         if (verbose)
 582                                 warning(" ... trying to fall back to cpu-clock-ticks\n");
 583
 584                         attr->type = PERF_TYPE_SOFTWARE;
 585                         attr->config = PERF_COUNT_SW_CPU_CLOCK;
 586                         goto try_again;
 587                 }
 588                 printf("\n");
 589                 error("perfcounter syscall returned with %d (%s)\n",
 590                         fd[i][counter], strerror(err));
 591                 die("No CONFIG_PERF_COUNTERS=y kernel support configured?\n");
 592                 exit(-1);
 593         }
 594         assert(fd[i][counter] >= 0);
 595         fcntl(fd[i][counter], F_SETFL, O_NONBLOCK);
 596
 597         /*
 598          * First counter acts as the group leader:
 599          */
 600         if (group && group_fd == -1)
 601                 group_fd = fd[i][counter];
 602
 603         event_array[nr_poll].fd = fd[i][counter];
 604         event_array[nr_poll].events = POLLIN;
 605         nr_poll++;
 606
 607         mmap_array[i][counter].counter = counter;
 608         mmap_array[i][counter].prev = 0;
 609         mmap_array[i][counter].mask = mmap_pages*page_size - 1;
 610         mmap_array[i][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
 611                         PROT_READ, MAP_SHARED, fd[i][counter], 0);
 612         if (mmap_array[i][counter].base == MAP_FAILED)
 613                 die("failed to mmap with %d (%s)\n", errno, strerror(errno));
 614 }
 615
 616 static int __cmd_top(void)
 617 {
 618         pthread_t thread;
 619         int i, counter;
 620         int ret;
 621
 622         for (i = 0; i < nr_cpus; i++) {
 623                 group_fd = -1;
 624                 for (counter = 0; counter < nr_counters; counter++)
 625                         start_counter(i, counter);
 626         }
 627
 628         /* Wait for a minimal set of events before starting the snapshot */
 629         poll(event_array, nr_poll, 100);
 630
 631         mmap_read();
 632
 633         if (pthread_create(&thread, NULL, display_thread, NULL)) {
 634                 printf("Could not create display thread.\n");
 635                 exit(-1);
 636         }
 637
 638         if (realtime_prio) {
 639                 struct sched_param param;
 640
 641                 param.sched_priority = realtime_prio;
 642                 if (sched_setscheduler(0, SCHED_FIFO, &param)) {
 643                         printf("Could not set realtime priority.\n");
 644                         exit(-1);
 645                 }
 646         }
 647
 648         while (1) {
 649                 int hits = samples;
 650
 651                 mmap_read();
 652
 653                 if (hits == samples)
 654                         ret = poll(event_array, nr_poll, 100);
 655         }
 656
 657         return 0;
 658 }
 659
 660 static const char * const top_usage[] = {
 661         "perf top [<options>]",
 662         NULL
 663 };
 664
 665 static const struct option options[] = {
 666         OPT_CALLBACK('e', "event", NULL, "event",
 667                      "event selector. use 'perf list' to list available events",
 668                      parse_events),
 669         OPT_INTEGER('c', "count", &default_interval,
 670                     "event period to sample"),
 671         OPT_INTEGER('p', "pid", &target_pid,
 672                     "profile events on existing pid"),
 673         OPT_BOOLEAN('a', "all-cpus", &system_wide,
 674                             "system-wide collection from all CPUs"),
 675         OPT_INTEGER('C', "CPU", &profile_cpu,
 676                     "CPU to profile on"),
 677         OPT_STRING('k', "vmlinux", &vmlinux, "file", "vmlinux pathname"),
 678         OPT_INTEGER('m', "mmap-pages", &mmap_pages,
 679                     "number of mmap data pages"),
 680         OPT_INTEGER('r', "realtime", &realtime_prio,
 681                     "collect data with this RT SCHED_FIFO priority"),
 682         OPT_INTEGER('d', "delay", &delay_secs,
 683                     "number of seconds to delay between refreshes"),
 684         OPT_BOOLEAN('D', "dump-symtab", &dump_symtab,
 685                             "dump the symbol table used for profiling"),
 686         OPT_INTEGER('f', "count-filter", &count_filter,
 687                     "only display functions with more events than this"),
 688         OPT_BOOLEAN('g', "group", &group,
 689                             "put the counters into a counter group"),
 690         OPT_BOOLEAN('i', "inherit", &inherit,
 691                     "child tasks inherit counters"),
 692         OPT_STRING('s', "sym-filter", &sym_filter, "pattern",
 693                     "only display symbols matchig this pattern"),
 694         OPT_BOOLEAN('z', "zero", &zero,
 695                     "zero history across updates"),
 696         OPT_INTEGER('F', "freq", &freq,
 697                     "profile at this frequency"),
 698         OPT_INTEGER('E', "entries", &print_entries,
 699                     "display this many functions"),
 700         OPT_BOOLEAN('v', "verbose", &verbose,
 701                     "be more verbose (show counter open errors, etc)"),
 702         OPT_END()
 703 };
 704
 705 int cmd_top(int argc, const char **argv, const char *prefix __used)
 706 {
 707         int counter;
 708
 709         symbol__init();
 710
 711         page_size = sysconf(_SC_PAGE_SIZE);
 712
 713         argc = parse_options(argc, argv, options, top_usage, 0);
 714         if (argc)
 715                 usage_with_options(top_usage, options);
 716
 717         if (freq) {
 718                 default_interval = freq;
 719                 freq = 1;
 720         }
 721
 722         /* CPU and PID are mutually exclusive */
 723         if (target_pid != -1 && profile_cpu != -1) {
 724                 printf("WARNING: PID switch overriding CPU\n");
 725                 sleep(1);
 726                 profile_cpu = -1;
 727         }
 728
 729         if (!nr_counters)
 730                 nr_counters = 1;
 731
 732         if (delay_secs < 1)
 733                 delay_secs = 1;
 734
 735         parse_symbols();
 736
 737         /*
 738          * Fill in the ones not specifically initialized via -c:
 739          */
 740         for (counter = 0; counter < nr_counters; counter++) {
 741                 if (attrs[counter].sample_period)
 742                         continue;
 743
 744                 attrs[counter].sample_period = default_interval;
 745         }
 746
 747         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 748         assert(nr_cpus <= MAX_NR_CPUS);
 749         assert(nr_cpus >= 0);
 750
 751         if (target_pid != -1 || profile_cpu != -1)
 752                 nr_cpus = 1;
 753
 754         return __cmd_top();
 755 }