SAFE public projects git trees. - safe/jmp/linux-2.6/blob - Documentation/perf_counter/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 "util/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                      system_wide                     =  0;
  52
  53 static __u64                    default_event_id[MAX_COUNTERS]          = {
  54         EID(PERF_TYPE_SOFTWARE, PERF_COUNT_TASK_CLOCK),
  55         EID(PERF_TYPE_SOFTWARE, PERF_COUNT_CONTEXT_SWITCHES),
  56         EID(PERF_TYPE_SOFTWARE, PERF_COUNT_CPU_MIGRATIONS),
  57         EID(PERF_TYPE_SOFTWARE, PERF_COUNT_PAGE_FAULTS),
  58
  59         EID(PERF_TYPE_HARDWARE, PERF_COUNT_CPU_CYCLES),
  60         EID(PERF_TYPE_HARDWARE, PERF_COUNT_INSTRUCTIONS),
  61         EID(PERF_TYPE_HARDWARE, PERF_COUNT_CACHE_REFERENCES),
  62         EID(PERF_TYPE_HARDWARE, PERF_COUNT_CACHE_MISSES),
  63 };
  64 static int                      default_interval = 100000;
  65 static int                      event_count[MAX_COUNTERS];
  66 static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
  67
  68 static __u64                    count_filter                    =  5;
  69 static int                      print_entries                   = 15;
  70
  71 static int                      target_pid                      = -1;
  72 static int                      profile_cpu                     = -1;
  73 static int                      nr_cpus                         =  0;
  74 static unsigned int             realtime_prio                   =  0;
  75 static int                      group                           =  0;
  76 static unsigned int             page_size;
  77 static unsigned int             mmap_pages                      = 16;
  78 static int                      freq                            =  0;
  79
  80 static char                     *sym_filter;
  81 static unsigned long            filter_start;
  82 static unsigned long            filter_end;
  83
  84 static int                      delay_secs                      =  2;
  85 static int                      zero;
  86 static int                      dump_symtab;
  87
  88 static const unsigned int default_count[] = {
  89         1000000,
  90         1000000,
  91           10000,
  92           10000,
  93         1000000,
  94           10000,
  95 };
  96
  97 /*
  98  * Symbols
  99  */
 100
 101 static uint64_t                 min_ip;
 102 static uint64_t                 max_ip = -1ll;
 103
 104 struct sym_entry {
 105         struct rb_node          rb_node;
 106         struct list_head        node;
 107         unsigned long           count[MAX_COUNTERS];
 108         unsigned long           snap_count;
 109         double                  weight;
 110         int                     skip;
 111 };
 112
 113 struct sym_entry                *sym_filter_entry;
 114
 115 struct dso *kernel_dso;
 116
 117 /*
 118  * Symbols will be added here in record_ip and will get out
 119  * after decayed.
 120  */
 121 static LIST_HEAD(active_symbols);
 122 static pthread_mutex_t active_symbols_lock = PTHREAD_MUTEX_INITIALIZER;
 123
 124 /*
 125  * Ordering weight: count-1 * count-2 * ... / count-n
 126  */
 127 static double sym_weight(const struct sym_entry *sym)
 128 {
 129         double weight = sym->snap_count;
 130         int counter;
 131
 132         for (counter = 1; counter < nr_counters-1; counter++)
 133                 weight *= sym->count[counter];
 134
 135         weight /= (sym->count[counter] + 1);
 136
 137         return weight;
 138 }
 139
 140 static long                     samples;
 141 static long                     userspace_samples;
 142 static const char               CONSOLE_CLEAR[] = "\e[H\e[2J";
 143
 144 static void __list_insert_active_sym(struct sym_entry *syme)
 145 {
 146         list_add(&syme->node, &active_symbols);
 147 }
 148
 149 static void list_remove_active_sym(struct sym_entry *syme)
 150 {
 151         pthread_mutex_lock(&active_symbols_lock);
 152         list_del_init(&syme->node);
 153         pthread_mutex_unlock(&active_symbols_lock);
 154 }
 155
 156 static void rb_insert_active_sym(struct rb_root *tree, struct sym_entry *se)
 157 {
 158         struct rb_node **p = &tree->rb_node;
 159         struct rb_node *parent = NULL;
 160         struct sym_entry *iter;
 161
 162         while (*p != NULL) {
 163                 parent = *p;
 164                 iter = rb_entry(parent, struct sym_entry, rb_node);
 165
 166                 if (se->weight > iter->weight)
 167                         p = &(*p)->rb_left;
 168                 else
 169                         p = &(*p)->rb_right;
 170         }
 171
 172         rb_link_node(&se->rb_node, parent, p);
 173         rb_insert_color(&se->rb_node, tree);
 174 }
 175
 176 static void print_sym_table(void)
 177 {
 178         int printed = 0, j;
 179         int counter;
 180         float samples_per_sec = samples/delay_secs;
 181         float ksamples_per_sec = (samples-userspace_samples)/delay_secs;
 182         float sum_ksamples = 0.0;
 183         struct sym_entry *syme, *n;
 184         struct rb_root tmp = RB_ROOT;
 185         struct rb_node *nd;
 186
 187         samples = userspace_samples = 0;
 188
 189         /* Sort the active symbols */
 190         pthread_mutex_lock(&active_symbols_lock);
 191         syme = list_entry(active_symbols.next, struct sym_entry, node);
 192         pthread_mutex_unlock(&active_symbols_lock);
 193
 194         list_for_each_entry_safe_from(syme, n, &active_symbols, node) {
 195                 syme->snap_count = syme->count[0];
 196                 if (syme->snap_count != 0) {
 197                         syme->weight = sym_weight(syme);
 198                         rb_insert_active_sym(&tmp, syme);
 199                         sum_ksamples += syme->snap_count;
 200
 201                         for (j = 0; j < nr_counters; j++)
 202                                 syme->count[j] = zero ? 0 : syme->count[j] * 7 / 8;
 203                 } else
 204                         list_remove_active_sym(syme);
 205         }
 206
 207         puts(CONSOLE_CLEAR);
 208
 209         printf(
 210 "------------------------------------------------------------------------------\n");
 211         printf( "   PerfTop:%8.0f irqs/sec  kernel:%4.1f%% [",
 212                 samples_per_sec,
 213                 100.0 - (100.0*((samples_per_sec-ksamples_per_sec)/samples_per_sec)));
 214
 215         if (nr_counters == 1) {
 216                 printf("%d", event_count[0]);
 217                 if (freq)
 218                         printf("Hz ");
 219                 else
 220                         printf(" ");
 221         }
 222
 223         for (counter = 0; counter < nr_counters; counter++) {
 224                 if (counter)
 225                         printf("/");
 226
 227                 printf("%s", event_name(counter));
 228         }
 229
 230         printf( "], ");
 231
 232         if (target_pid != -1)
 233                 printf(" (target_pid: %d", target_pid);
 234         else
 235                 printf(" (all");
 236
 237         if (profile_cpu != -1)
 238                 printf(", cpu: %d)\n", profile_cpu);
 239         else {
 240                 if (target_pid != -1)
 241                         printf(")\n");
 242                 else
 243                         printf(", %d CPUs)\n", nr_cpus);
 244         }
 245
 246         printf("------------------------------------------------------------------------------\n\n");
 247
 248         if (nr_counters == 1)
 249                 printf("             samples    pcnt");
 250         else
 251                 printf("  weight     samples    pcnt");
 252
 253         printf("         RIP          kernel function\n"
 254                        "  ______     _______   _____   ________________   _______________\n\n"
 255         );
 256
 257         for (nd = rb_first(&tmp); nd; nd = rb_next(nd)) {
 258                 struct sym_entry *syme = rb_entry(nd, struct sym_entry, rb_node);
 259                 struct symbol *sym = (struct symbol *)(syme + 1);
 260                 char *color = PERF_COLOR_NORMAL;
 261                 double pcnt;
 262
 263                 if (++printed > print_entries || syme->snap_count < count_filter)
 264                         continue;
 265
 266                 pcnt = 100.0 - (100.0 * ((sum_ksamples - syme->snap_count) /
 267                                          sum_ksamples));
 268
 269                 /*
 270                  * We color high-overhead entries in red, low-overhead
 271                  * entries in green - and keep the middle ground normal:
 272                  */
 273                 if (pcnt >= 5.0)
 274                         color = PERF_COLOR_RED;
 275                 if (pcnt < 0.5)
 276                         color = PERF_COLOR_GREEN;
 277
 278                 if (nr_counters == 1)
 279                         printf("%20.2f - ", syme->weight);
 280                 else
 281                         printf("%9.1f %10ld - ", syme->weight, syme->snap_count);
 282
 283                 color_fprintf(stdout, color, "%4.1f%%", pcnt);
 284                 printf(" - %016llx : %s\n", sym->start, sym->name);
 285         }
 286 }
 287
 288 static void *display_thread(void *arg)
 289 {
 290         struct pollfd stdin_poll = { .fd = 0, .events = POLLIN };
 291         int delay_msecs = delay_secs * 1000;
 292
 293         printf("PerfTop refresh period: %d seconds\n", delay_secs);
 294
 295         do {
 296                 print_sym_table();
 297         } while (!poll(&stdin_poll, 1, delay_msecs) == 1);
 298
 299         printf("key pressed - exiting.\n");
 300         exit(0);
 301
 302         return NULL;
 303 }
 304
 305 static int symbol_filter(struct dso *self, struct symbol *sym)
 306 {
 307         static int filter_match;
 308         struct sym_entry *syme;
 309         const char *name = sym->name;
 310
 311         if (!strcmp(name, "_text") ||
 312             !strcmp(name, "_etext") ||
 313             !strcmp(name, "_sinittext") ||
 314             !strncmp("init_module", name, 11) ||
 315             !strncmp("cleanup_module", name, 14) ||
 316             strstr(name, "_text_start") ||
 317             strstr(name, "_text_end"))
 318                 return 1;
 319
 320         syme = dso__sym_priv(self, sym);
 321         /* Tag samples to be skipped. */
 322         if (!strcmp("default_idle", name) ||
 323             !strcmp("cpu_idle", name) ||
 324             !strcmp("enter_idle", name) ||
 325             !strcmp("exit_idle", name) ||
 326             !strcmp("mwait_idle", name))
 327                 syme->skip = 1;
 328
 329         if (filter_match == 1) {
 330                 filter_end = sym->start;
 331                 filter_match = -1;
 332                 if (filter_end - filter_start > 10000) {
 333                         fprintf(stderr,
 334                                 "hm, too large filter symbol <%s> - skipping.\n",
 335                                 sym_filter);
 336                         fprintf(stderr, "symbol filter start: %016lx\n",
 337                                 filter_start);
 338                         fprintf(stderr, "                end: %016lx\n",
 339                                 filter_end);
 340                         filter_end = filter_start = 0;
 341                         sym_filter = NULL;
 342                         sleep(1);
 343                 }
 344         }
 345
 346         if (filter_match == 0 && sym_filter && !strcmp(name, sym_filter)) {
 347                 filter_match = 1;
 348                 filter_start = sym->start;
 349         }
 350
 351
 352         return 0;
 353 }
 354
 355 static int parse_symbols(void)
 356 {
 357         struct rb_node *node;
 358         struct symbol  *sym;
 359
 360         kernel_dso = dso__new("[kernel]", sizeof(struct sym_entry));
 361         if (kernel_dso == NULL)
 362                 return -1;
 363
 364         if (dso__load_kernel(kernel_dso, NULL, symbol_filter, 1) != 0)
 365                 goto out_delete_dso;
 366
 367         node = rb_first(&kernel_dso->syms);
 368         sym = rb_entry(node, struct symbol, rb_node);
 369         min_ip = sym->start;
 370
 371         node = rb_last(&kernel_dso->syms);
 372         sym = rb_entry(node, struct symbol, rb_node);
 373         max_ip = sym->end;
 374
 375         if (dump_symtab)
 376                 dso__fprintf(kernel_dso, stderr);
 377
 378         return 0;
 379
 380 out_delete_dso:
 381         dso__delete(kernel_dso);
 382         kernel_dso = NULL;
 383         return -1;
 384 }
 385
 386 #define TRACE_COUNT     3
 387
 388 /*
 389  * Binary search in the histogram table and record the hit:
 390  */
 391 static void record_ip(uint64_t ip, int counter)
 392 {
 393         struct symbol *sym = dso__find_symbol(kernel_dso, ip);
 394
 395         if (sym != NULL) {
 396                 struct sym_entry *syme = dso__sym_priv(kernel_dso, sym);
 397
 398                 if (!syme->skip) {
 399                         syme->count[counter]++;
 400                         pthread_mutex_lock(&active_symbols_lock);
 401                         if (list_empty(&syme->node) || !syme->node.next)
 402                                 __list_insert_active_sym(syme);
 403                         pthread_mutex_unlock(&active_symbols_lock);
 404                         return;
 405                 }
 406         }
 407
 408         samples--;
 409 }
 410
 411 static void process_event(uint64_t ip, int counter)
 412 {
 413         samples++;
 414
 415         if (ip < min_ip || ip > max_ip) {
 416                 userspace_samples++;
 417                 return;
 418         }
 419
 420         record_ip(ip, counter);
 421 }
 422
 423 struct mmap_data {
 424         int counter;
 425         void *base;
 426         unsigned int mask;
 427         unsigned int prev;
 428 };
 429
 430 static unsigned int mmap_read_head(struct mmap_data *md)
 431 {
 432         struct perf_counter_mmap_page *pc = md->base;
 433         int head;
 434
 435         head = pc->data_head;
 436         rmb();
 437
 438         return head;
 439 }
 440
 441 struct timeval last_read, this_read;
 442
 443 static void mmap_read(struct mmap_data *md)
 444 {
 445         unsigned int head = mmap_read_head(md);
 446         unsigned int old = md->prev;
 447         unsigned char *data = md->base + page_size;
 448         int diff;
 449
 450         gettimeofday(&this_read, NULL);
 451
 452         /*
 453          * If we're further behind than half the buffer, there's a chance
 454          * the writer will bite our tail and mess up the samples under us.
 455          *
 456          * If we somehow ended up ahead of the head, we got messed up.
 457          *
 458          * In either case, truncate and restart at head.
 459          */
 460         diff = head - old;
 461         if (diff > md->mask / 2 || diff < 0) {
 462                 struct timeval iv;
 463                 unsigned long msecs;
 464
 465                 timersub(&this_read, &last_read, &iv);
 466                 msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
 467
 468                 fprintf(stderr, "WARNING: failed to keep up with mmap data."
 469                                 "  Last read %lu msecs ago.\n", msecs);
 470
 471                 /*
 472                  * head points to a known good entry, start there.
 473                  */
 474                 old = head;
 475         }
 476
 477         last_read = this_read;
 478
 479         for (; old != head;) {
 480                 struct ip_event {
 481                         struct perf_event_header header;
 482                         __u64 ip;
 483                         __u32 pid, target_pid;
 484                 };
 485                 struct mmap_event {
 486                         struct perf_event_header header;
 487                         __u32 pid, target_pid;
 488                         __u64 start;
 489                         __u64 len;
 490                         __u64 pgoff;
 491                         char filename[PATH_MAX];
 492                 };
 493
 494                 typedef union event_union {
 495                         struct perf_event_header header;
 496                         struct ip_event ip;
 497                         struct mmap_event mmap;
 498                 } event_t;
 499
 500                 event_t *event = (event_t *)&data[old & md->mask];
 501
 502                 event_t event_copy;
 503
 504                 size_t size = event->header.size;
 505
 506                 /*
 507                  * Event straddles the mmap boundary -- header should always
 508                  * be inside due to u64 alignment of output.
 509                  */
 510                 if ((old & md->mask) + size != ((old + size) & md->mask)) {
 511                         unsigned int offset = old;
 512                         unsigned int len = min(sizeof(*event), size), cpy;
 513                         void *dst = &event_copy;
 514
 515                         do {
 516                                 cpy = min(md->mask + 1 - (offset & md->mask), len);
 517                                 memcpy(dst, &data[offset & md->mask], cpy);
 518                                 offset += cpy;
 519                                 dst += cpy;
 520                                 len -= cpy;
 521                         } while (len);
 522
 523                         event = &event_copy;
 524                 }
 525
 526                 old += size;
 527
 528                 if (event->header.misc & PERF_EVENT_MISC_OVERFLOW) {
 529                         if (event->header.type & PERF_SAMPLE_IP)
 530                                 process_event(event->ip.ip, md->counter);
 531                 }
 532         }
 533
 534         md->prev = old;
 535 }
 536
 537 static struct pollfd event_array[MAX_NR_CPUS * MAX_COUNTERS];
 538 static struct mmap_data mmap_array[MAX_NR_CPUS][MAX_COUNTERS];
 539
 540 static int __cmd_top(void)
 541 {
 542         struct perf_counter_attr attr;
 543         pthread_t thread;
 544         int i, counter, group_fd, nr_poll = 0;
 545         unsigned int cpu;
 546         int ret;
 547
 548         for (i = 0; i < nr_cpus; i++) {
 549                 group_fd = -1;
 550                 for (counter = 0; counter < nr_counters; counter++) {
 551
 552                         cpu     = profile_cpu;
 553                         if (target_pid == -1 && profile_cpu == -1)
 554                                 cpu = i;
 555
 556                         memset(&attr, 0, sizeof(attr));
 557                         attr.config             = event_id[counter];
 558                         attr.sample_period      = event_count[counter];
 559                         attr.sample_type        = PERF_SAMPLE_IP | PERF_SAMPLE_TID;
 560                         attr.freq               = freq;
 561
 562                         fd[i][counter] = sys_perf_counter_open(&attr, target_pid, cpu, group_fd, 0);
 563                         if (fd[i][counter] < 0) {
 564                                 int err = errno;
 565
 566                                 error("syscall returned with %d (%s)\n",
 567                                         fd[i][counter], strerror(err));
 568                                 if (err == EPERM)
 569                                         printf("Are you root?\n");
 570                                 exit(-1);
 571                         }
 572                         assert(fd[i][counter] >= 0);
 573                         fcntl(fd[i][counter], F_SETFL, O_NONBLOCK);
 574
 575                         /*
 576                          * First counter acts as the group leader:
 577                          */
 578                         if (group && group_fd == -1)
 579                                 group_fd = fd[i][counter];
 580
 581                         event_array[nr_poll].fd = fd[i][counter];
 582                         event_array[nr_poll].events = POLLIN;
 583                         nr_poll++;
 584
 585                         mmap_array[i][counter].counter = counter;
 586                         mmap_array[i][counter].prev = 0;
 587                         mmap_array[i][counter].mask = mmap_pages*page_size - 1;
 588                         mmap_array[i][counter].base = mmap(NULL, (mmap_pages+1)*page_size,
 589                                         PROT_READ, MAP_SHARED, fd[i][counter], 0);
 590                         if (mmap_array[i][counter].base == MAP_FAILED)
 591                                 die("failed to mmap with %d (%s)\n", errno, strerror(errno));
 592                 }
 593         }
 594
 595         if (pthread_create(&thread, NULL, display_thread, NULL)) {
 596                 printf("Could not create display thread.\n");
 597                 exit(-1);
 598         }
 599
 600         if (realtime_prio) {
 601                 struct sched_param param;
 602
 603                 param.sched_priority = realtime_prio;
 604                 if (sched_setscheduler(0, SCHED_FIFO, &param)) {
 605                         printf("Could not set realtime priority.\n");
 606                         exit(-1);
 607                 }
 608         }
 609
 610         while (1) {
 611                 int hits = samples;
 612
 613                 for (i = 0; i < nr_cpus; i++) {
 614                         for (counter = 0; counter < nr_counters; counter++)
 615                                 mmap_read(&mmap_array[i][counter]);
 616                 }
 617
 618                 if (hits == samples)
 619                         ret = poll(event_array, nr_poll, 100);
 620         }
 621
 622         return 0;
 623 }
 624
 625 static const char * const top_usage[] = {
 626         "perf top [<options>]",
 627         NULL
 628 };
 629
 630 static char events_help_msg[EVENTS_HELP_MAX];
 631
 632 static const struct option options[] = {
 633         OPT_CALLBACK('e', "event", NULL, "event",
 634                      events_help_msg, parse_events),
 635         OPT_INTEGER('c', "count", &default_interval,
 636                     "event period to sample"),
 637         OPT_INTEGER('p', "pid", &target_pid,
 638                     "profile events on existing pid"),
 639         OPT_BOOLEAN('a', "all-cpus", &system_wide,
 640                             "system-wide collection from all CPUs"),
 641         OPT_INTEGER('C', "CPU", &profile_cpu,
 642                     "CPU to profile on"),
 643         OPT_INTEGER('m', "mmap-pages", &mmap_pages,
 644                     "number of mmap data pages"),
 645         OPT_INTEGER('r', "realtime", &realtime_prio,
 646                     "collect data with this RT SCHED_FIFO priority"),
 647         OPT_INTEGER('d', "delay", &delay_secs,
 648                     "number of seconds to delay between refreshes"),
 649         OPT_BOOLEAN('D', "dump-symtab", &dump_symtab,
 650                             "dump the symbol table used for profiling"),
 651         OPT_INTEGER('f', "count-filter", &count_filter,
 652                     "only display functions with more events than this"),
 653         OPT_BOOLEAN('g', "group", &group,
 654                             "put the counters into a counter group"),
 655         OPT_STRING('s', "sym-filter", &sym_filter, "pattern",
 656                     "only display symbols matchig this pattern"),
 657         OPT_BOOLEAN('z', "zero", &group,
 658                     "zero history across updates"),
 659         OPT_INTEGER('F', "freq", &freq,
 660                     "profile at this frequency"),
 661         OPT_INTEGER('E', "entries", &print_entries,
 662                     "display this many functions"),
 663         OPT_END()
 664 };
 665
 666 int cmd_top(int argc, const char **argv, const char *prefix)
 667 {
 668         int counter;
 669
 670         page_size = sysconf(_SC_PAGE_SIZE);
 671
 672         create_events_help(events_help_msg);
 673         memcpy(event_id, default_event_id, sizeof(default_event_id));
 674
 675         argc = parse_options(argc, argv, options, top_usage, 0);
 676         if (argc)
 677                 usage_with_options(top_usage, options);
 678
 679         if (freq) {
 680                 default_interval = freq;
 681                 freq = 1;
 682         }
 683
 684         /* CPU and PID are mutually exclusive */
 685         if (target_pid != -1 && profile_cpu != -1) {
 686                 printf("WARNING: PID switch overriding CPU\n");
 687                 sleep(1);
 688                 profile_cpu = -1;
 689         }
 690
 691         if (!nr_counters) {
 692                 nr_counters = 1;
 693                 event_id[0] = 0;
 694         }
 695
 696         for (counter = 0; counter < nr_counters; counter++) {
 697                 if (event_count[counter])
 698                         continue;
 699
 700                 event_count[counter] = default_interval;
 701         }
 702
 703         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 704         assert(nr_cpus <= MAX_NR_CPUS);
 705         assert(nr_cpus >= 0);
 706
 707         if (target_pid != -1 || profile_cpu != -1)
 708                 nr_cpus = 1;
 709
 710         parse_symbols();
 711
 712         return __cmd_top();
 713 }