tools/perf/builtin-stat.c

   1 /*
   2  * builtin-stat.c
   3  *
   4  * Builtin stat command: Give a precise performance counters summary
   5  * overview about any workload, CPU or specific PID.
   6  *
   7  * Sample output:
   8
   9    $ perf stat ~/hackbench 10
  10    Time: 0.104
  11
  12     Performance counter stats for '/home/mingo/hackbench':
  13
  14        1255.538611  task clock ticks     #      10.143 CPU utilization factor
  15              54011  context switches     #       0.043 M/sec
  16                385  CPU migrations       #       0.000 M/sec
  17              17755  pagefaults           #       0.014 M/sec
  18         3808323185  CPU cycles           #    3033.219 M/sec
  19         1575111190  instructions         #    1254.530 M/sec
  20           17367895  cache references     #      13.833 M/sec
  21            7674421  cache misses         #       6.112 M/sec
  22
  23     Wall-clock time elapsed:   123.786620 msecs
  24
  25  *
  26  * Copyright (C) 2008, Red Hat Inc, Ingo Molnar <mingo@redhat.com>
  27  *
  28  * Improvements and fixes by:
  29  *
  30  *   Arjan van de Ven <arjan@linux.intel.com>
  31  *   Yanmin Zhang <yanmin.zhang@intel.com>
  32  *   Wu Fengguang <fengguang.wu@intel.com>
  33  *   Mike Galbraith <efault@gmx.de>
  34  *   Paul Mackerras <paulus@samba.org>
  35  *   Jaswinder Singh Rajput <jaswinder@kernel.org>
  36  *
  37  * Released under the GPL v2. (and only v2, not any later version)
  38  */
  39
  40 #include "perf.h"
  41 #include "builtin.h"
  42 #include "util/util.h"
  43 #include "util/parse-options.h"
  44 #include "util/parse-events.h"
  45 #include "util/event.h"
  46 #include "util/debug.h"
  47 #include "util/header.h"
  48
  49 #include <sys/prctl.h>
  50 #include <math.h>
  51
  52 static struct perf_event_attr default_attrs[] = {
  53
  54   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_TASK_CLOCK              },
  55   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CONTEXT_SWITCHES        },
  56   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_MIGRATIONS          },
  57   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_PAGE_FAULTS             },
  58
  59   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES              },
  60   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_INSTRUCTIONS            },
  61   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS     },
  62   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_MISSES           },
  63   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_REFERENCES        },
  64   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_MISSES            },
  65
  66 };
  67
  68 static int                      system_wide                     =  0;
  69 static unsigned int             nr_cpus                         =  0;
  70 static int                      run_idx                         =  0;
  71
  72 static int                      run_count                       =  1;
  73 static int                      inherit                         =  1;
  74 static int                      scale                           =  1;
  75 static pid_t                    target_pid                      = -1;
  76 static pid_t                    child_pid                       = -1;
  77 static int                      null_run                        =  0;
  78
  79 static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
  80
  81 static int                      event_scaled[MAX_COUNTERS];
  82
  83 static volatile int done = 0;
  84
  85 struct stats
  86 {
  87         double n, mean, M2;
  88 };
  89
  90 static void update_stats(struct stats *stats, u64 val)
  91 {
  92         double delta;
  93
  94         stats->n++;
  95         delta = val - stats->mean;
  96         stats->mean += delta / stats->n;
  97         stats->M2 += delta*(val - stats->mean);
  98 }
  99
 100 static double avg_stats(struct stats *stats)
 101 {
 102         return stats->mean;
 103 }
 104
 105 /*
 106  * http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance
 107  *
 108  *       (\Sum n_i^2) - ((\Sum n_i)^2)/n
 109  * s^2 = -------------------------------
 110  *                  n - 1
 111  *
 112  * http://en.wikipedia.org/wiki/Stddev
 113  *
 114  * The std dev of the mean is related to the std dev by:
 115  *
 116  *             s
 117  * s_mean = -------
 118  *          sqrt(n)
 119  *
 120  */
 121 static double stddev_stats(struct stats *stats)
 122 {
 123         double variance = stats->M2 / (stats->n - 1);
 124         double variance_mean = variance / stats->n;
 125
 126         return sqrt(variance_mean);
 127 }
 128
 129 struct stats                    event_res_stats[MAX_COUNTERS][3];
 130 struct stats                    runtime_nsecs_stats;
 131 struct stats                    walltime_nsecs_stats;
 132 struct stats                    runtime_cycles_stats;
 133 struct stats                    runtime_branches_stats;
 134
 135 #define MATCH_EVENT(t, c, counter)                      \
 136         (attrs[counter].type == PERF_TYPE_##t &&        \
 137          attrs[counter].config == PERF_COUNT_##c)
 138
 139 #define ERR_PERF_OPEN \
 140 "Error: counter %d, sys_perf_event_open() syscall returned with %d (%s)\n"
 141
 142 static void create_perf_stat_counter(int counter, int pid)
 143 {
 144         struct perf_event_attr *attr = attrs + counter;
 145
 146         if (scale)
 147                 attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
 148                                     PERF_FORMAT_TOTAL_TIME_RUNNING;
 149
 150         if (system_wide) {
 151                 unsigned int cpu;
 152
 153                 for (cpu = 0; cpu < nr_cpus; cpu++) {
 154                         fd[cpu][counter] = sys_perf_event_open(attr, -1, cpu, -1, 0);
 155                         if (fd[cpu][counter] < 0 && verbose)
 156                                 fprintf(stderr, ERR_PERF_OPEN, counter,
 157                                         fd[cpu][counter], strerror(errno));
 158                 }
 159         } else {
 160                 attr->inherit        = inherit;
 161                 attr->disabled       = 1;
 162                 attr->enable_on_exec = 1;
 163
 164                 fd[0][counter] = sys_perf_event_open(attr, pid, -1, -1, 0);
 165                 if (fd[0][counter] < 0 && verbose)
 166                         fprintf(stderr, ERR_PERF_OPEN, counter,
 167                                 fd[0][counter], strerror(errno));
 168         }
 169 }
 170
 171 /*
 172  * Does the counter have nsecs as a unit?
 173  */
 174 static inline int nsec_counter(int counter)
 175 {
 176         if (MATCH_EVENT(SOFTWARE, SW_CPU_CLOCK, counter) ||
 177             MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter))
 178                 return 1;
 179
 180         return 0;
 181 }
 182
 183 /*
 184  * Read out the results of a single counter:
 185  */
 186 static void read_counter(int counter)
 187 {
 188         u64 count[3], single_count[3];
 189         unsigned int cpu;
 190         size_t res, nv;
 191         int scaled;
 192         int i;
 193
 194         count[0] = count[1] = count[2] = 0;
 195
 196         nv = scale ? 3 : 1;
 197         for (cpu = 0; cpu < nr_cpus; cpu++) {
 198                 if (fd[cpu][counter] < 0)
 199                         continue;
 200
 201                 res = read(fd[cpu][counter], single_count, nv * sizeof(u64));
 202                 assert(res == nv * sizeof(u64));
 203
 204                 close(fd[cpu][counter]);
 205                 fd[cpu][counter] = -1;
 206
 207                 count[0] += single_count[0];
 208                 if (scale) {
 209                         count[1] += single_count[1];
 210                         count[2] += single_count[2];
 211                 }
 212         }
 213
 214         scaled = 0;
 215         if (scale) {
 216                 if (count[2] == 0) {
 217                         event_scaled[counter] = -1;
 218                         count[0] = 0;
 219                         return;
 220                 }
 221
 222                 if (count[2] < count[1]) {
 223                         event_scaled[counter] = 1;
 224                         count[0] = (unsigned long long)
 225                                 ((double)count[0] * count[1] / count[2] + 0.5);
 226                 }
 227         }
 228
 229         for (i = 0; i < 3; i++)
 230                 update_stats(&event_res_stats[counter][i], count[i]);
 231
 232         if (verbose) {
 233                 fprintf(stderr, "%s: %Ld %Ld %Ld\n", event_name(counter),
 234                                 count[0], count[1], count[2]);
 235         }
 236
 237         /*
 238          * Save the full runtime - to allow normalization during printout:
 239          */
 240         if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter))
 241                 update_stats(&runtime_nsecs_stats, count[0]);
 242         if (MATCH_EVENT(HARDWARE, HW_CPU_CYCLES, counter))
 243                 update_stats(&runtime_cycles_stats, count[0]);
 244         if (MATCH_EVENT(HARDWARE, HW_BRANCH_INSTRUCTIONS, counter))
 245                 update_stats(&runtime_branches_stats, count[0]);
 246 }
 247
 248 static int run_perf_stat(int argc __used, const char **argv)
 249 {
 250         unsigned long long t0, t1;
 251         int status = 0;
 252         int counter;
 253         int pid = target_pid;
 254         int child_ready_pipe[2], go_pipe[2];
 255         const bool forks = (target_pid == -1 && argc > 0);
 256         char buf;
 257
 258         if (!system_wide)
 259                 nr_cpus = 1;
 260
 261         if (forks && (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) {
 262                 perror("failed to create pipes");
 263                 exit(1);
 264         }
 265
 266         if (forks) {
 267                 if ((pid = fork()) < 0)
 268                         perror("failed to fork");
 269
 270                 if (!pid) {
 271                         close(child_ready_pipe[0]);
 272                         close(go_pipe[1]);
 273                         fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
 274
 275                         /*
 276                          * Do a dummy execvp to get the PLT entry resolved,
 277                          * so we avoid the resolver overhead on the real
 278                          * execvp call.
 279                          */
 280                         execvp("", (char **)argv);
 281
 282                         /*
 283                          * Tell the parent we're ready to go
 284                          */
 285                         close(child_ready_pipe[1]);
 286
 287                         /*
 288                          * Wait until the parent tells us to go.
 289                          */
 290                         if (read(go_pipe[0], &buf, 1) == -1)
 291                                 perror("unable to read pipe");
 292
 293                         execvp(argv[0], (char **)argv);
 294
 295                         perror(argv[0]);
 296                         exit(-1);
 297                 }
 298
 299                 child_pid = pid;
 300
 301                 /*
 302                  * Wait for the child to be ready to exec.
 303                  */
 304                 close(child_ready_pipe[1]);
 305                 close(go_pipe[0]);
 306                 if (read(child_ready_pipe[0], &buf, 1) == -1)
 307                         perror("unable to read pipe");
 308                 close(child_ready_pipe[0]);
 309         }
 310
 311         for (counter = 0; counter < nr_counters; counter++)
 312                 create_perf_stat_counter(counter, pid);
 313
 314         /*
 315          * Enable counters and exec the command:
 316          */
 317         t0 = rdclock();
 318
 319         if (forks) {
 320                 close(go_pipe[1]);
 321                 wait(&status);
 322         } else {
 323                 while(!done);
 324         }
 325
 326         t1 = rdclock();
 327
 328         update_stats(&walltime_nsecs_stats, t1 - t0);
 329
 330         for (counter = 0; counter < nr_counters; counter++)
 331                 read_counter(counter);
 332
 333         return WEXITSTATUS(status);
 334 }
 335
 336 static void print_noise(int counter, double avg)
 337 {
 338         if (run_count == 1)
 339                 return;
 340
 341         fprintf(stderr, "   ( +- %7.3f%% )",
 342                         100 * stddev_stats(&event_res_stats[counter][0]) / avg);
 343 }
 344
 345 static void nsec_printout(int counter, double avg)
 346 {
 347         double msecs = avg / 1e6;
 348
 349         fprintf(stderr, " %14.6f  %-24s", msecs, event_name(counter));
 350
 351         if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) {
 352                 fprintf(stderr, " # %10.3f CPUs ",
 353                                 avg / avg_stats(&walltime_nsecs_stats));
 354         }
 355 }
 356
 357 static void abs_printout(int counter, double avg)
 358 {
 359         double total, ratio = 0.0;
 360
 361         fprintf(stderr, " %14.0f  %-24s", avg, event_name(counter));
 362
 363         if (MATCH_EVENT(HARDWARE, HW_INSTRUCTIONS, counter)) {
 364                 total = avg_stats(&runtime_cycles_stats);
 365
 366                 if (total)
 367                         ratio = avg / total;
 368
 369                 fprintf(stderr, " # %10.3f IPC  ", ratio);
 370         } else if (MATCH_EVENT(HARDWARE, HW_BRANCH_MISSES, counter) &&
 371                         runtime_branches_stats.n != 0) {
 372                 total = avg_stats(&runtime_branches_stats);
 373
 374                 if (total)
 375                         ratio = avg * 100 / total;
 376
 377                 fprintf(stderr, " # %10.3f %%    ", ratio);
 378
 379         } else if (runtime_nsecs_stats.n != 0) {
 380                 total = avg_stats(&runtime_nsecs_stats);
 381
 382                 if (total)
 383                         ratio = 1000.0 * avg / total;
 384
 385                 fprintf(stderr, " # %10.3f M/sec", ratio);
 386         }
 387 }
 388
 389 /*
 390  * Print out the results of a single counter:
 391  */
 392 static void print_counter(int counter)
 393 {
 394         double avg = avg_stats(&event_res_stats[counter][0]);
 395         int scaled = event_scaled[counter];
 396
 397         if (scaled == -1) {
 398                 fprintf(stderr, " %14s  %-24s\n",
 399                         "<not counted>", event_name(counter));
 400                 return;
 401         }
 402
 403         if (nsec_counter(counter))
 404                 nsec_printout(counter, avg);
 405         else
 406                 abs_printout(counter, avg);
 407
 408         print_noise(counter, avg);
 409
 410         if (scaled) {
 411                 double avg_enabled, avg_running;
 412
 413                 avg_enabled = avg_stats(&event_res_stats[counter][1]);
 414                 avg_running = avg_stats(&event_res_stats[counter][2]);
 415
 416                 fprintf(stderr, "  (scaled from %.2f%%)",
 417                                 100 * avg_running / avg_enabled);
 418         }
 419
 420         fprintf(stderr, "\n");
 421 }
 422
 423 static void print_stat(int argc, const char **argv)
 424 {
 425         int i, counter;
 426
 427         fflush(stdout);
 428
 429         fprintf(stderr, "\n");
 430         fprintf(stderr, " Performance counter stats for ");
 431         if(target_pid == -1) {
 432                 fprintf(stderr, "\'%s", argv[0]);
 433                 for (i = 1; i < argc; i++)
 434                         fprintf(stderr, " %s", argv[i]);
 435         }else
 436                 fprintf(stderr, "task pid \'%d", target_pid);
 437
 438         fprintf(stderr, "\'");
 439         if (run_count > 1)
 440                 fprintf(stderr, " (%d runs)", run_count);
 441         fprintf(stderr, ":\n\n");
 442
 443         for (counter = 0; counter < nr_counters; counter++)
 444                 print_counter(counter);
 445
 446         fprintf(stderr, "\n");
 447         fprintf(stderr, " %14.9f  seconds time elapsed",
 448                         avg_stats(&walltime_nsecs_stats)/1e9);
 449         if (run_count > 1) {
 450                 fprintf(stderr, "   ( +- %7.3f%% )",
 451                                 100*stddev_stats(&walltime_nsecs_stats) /
 452                                 avg_stats(&walltime_nsecs_stats));
 453         }
 454         fprintf(stderr, "\n\n");
 455 }
 456
 457 static volatile int signr = -1;
 458
 459 static void skip_signal(int signo)
 460 {
 461         if(target_pid != -1)
 462                 done = 1;
 463
 464         signr = signo;
 465 }
 466
 467 static void sig_atexit(void)
 468 {
 469         if (child_pid != -1)
 470                 kill(child_pid, SIGTERM);
 471
 472         if (signr == -1)
 473                 return;
 474
 475         signal(signr, SIG_DFL);
 476         kill(getpid(), signr);
 477 }
 478
 479 static const char * const stat_usage[] = {
 480         "perf stat [<options>] [<command>]",
 481         NULL
 482 };
 483
 484 static const struct option options[] = {
 485         OPT_CALLBACK('e', "event", NULL, "event",
 486                      "event selector. use 'perf list' to list available events",
 487                      parse_events),
 488         OPT_BOOLEAN('i', "inherit", &inherit,
 489                     "child tasks inherit counters"),
 490         OPT_INTEGER('p', "pid", &target_pid,
 491                     "stat events on existing pid"),
 492         OPT_BOOLEAN('a', "all-cpus", &system_wide,
 493                     "system-wide collection from all CPUs"),
 494         OPT_BOOLEAN('c', "scale", &scale,
 495                     "scale/normalize counters"),
 496         OPT_BOOLEAN('v', "verbose", &verbose,
 497                     "be more verbose (show counter open errors, etc)"),
 498         OPT_INTEGER('r', "repeat", &run_count,
 499                     "repeat command and print average + stddev (max: 100)"),
 500         OPT_BOOLEAN('n', "null", &null_run,
 501                     "null run - dont start any counters"),
 502         OPT_END()
 503 };
 504
 505 int cmd_stat(int argc, const char **argv, const char *prefix __used)
 506 {
 507         int status;
 508
 509         argc = parse_options(argc, argv, options, stat_usage,
 510                 PARSE_OPT_STOP_AT_NON_OPTION);
 511         if (!argc && target_pid == -1)
 512                 usage_with_options(stat_usage, options);
 513         if (run_count <= 0)
 514                 usage_with_options(stat_usage, options);
 515
 516         /* Set attrs and nr_counters if no event is selected and !null_run */
 517         if (!null_run && !nr_counters) {
 518                 memcpy(attrs, default_attrs, sizeof(default_attrs));
 519                 nr_counters = ARRAY_SIZE(default_attrs);
 520         }
 521
 522         nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
 523         assert(nr_cpus <= MAX_NR_CPUS);
 524         assert((int)nr_cpus >= 0);
 525
 526         /*
 527          * We dont want to block the signals - that would cause
 528          * child tasks to inherit that and Ctrl-C would not work.
 529          * What we want is for Ctrl-C to work in the exec()-ed
 530          * task, but being ignored by perf stat itself:
 531          */
 532         atexit(sig_atexit);
 533         signal(SIGINT,  skip_signal);
 534         signal(SIGALRM, skip_signal);
 535         signal(SIGABRT, skip_signal);
 536
 537         status = 0;
 538         for (run_idx = 0; run_idx < run_count; run_idx++) {
 539                 if (run_count != 1 && verbose)
 540                         fprintf(stderr, "[ perf stat: executing run #%d ... ]\n", run_idx + 1);
 541                 status = run_perf_stat(argc, argv);
 542         }
 543
 544         print_stat(argc, argv);
 545
 546         return status;
 547 }