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 #include "util/cpumap.h"
  49
  50 #include <sys/prctl.h>
  51 #include <math.h>
  52
  53 static struct perf_event_attr default_attrs[] = {
  54
  55   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_TASK_CLOCK              },
  56   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CONTEXT_SWITCHES        },
  57   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_MIGRATIONS          },
  58   { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_PAGE_FAULTS             },
  59
  60   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES              },
  61   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_INSTRUCTIONS            },
  62   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS     },
  63   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_MISSES           },
  64   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_REFERENCES        },
  65   { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_MISSES            },
  66
  67 };
  68
  69 static int                      system_wide                     =  0;
  70 static unsigned int             nr_cpus                         =  0;
  71 static int                      run_idx                         =  0;
  72
  73 static int                      run_count                       =  1;
  74 static int                      inherit                         =  1;
  75 static int                      scale                           =  1;
  76 static pid_t                    target_pid                      = -1;
  77 static pid_t                    child_pid                       = -1;
  78 static int                      null_run                        =  0;
  79
  80 static int                      fd[MAX_NR_CPUS][MAX_COUNTERS];
  81
  82 static int                      event_scaled[MAX_COUNTERS];
  83
  84 static volatile int done = 0;
  85
  86 struct stats
  87 {
  88         double n, mean, M2;
  89 };
  90
  91 static void update_stats(struct stats *stats, u64 val)
  92 {
  93         double delta;
  94
  95         stats->n++;
  96         delta = val - stats->mean;
  97         stats->mean += delta / stats->n;
  98         stats->M2 += delta*(val - stats->mean);
  99 }
 100
 101 static double avg_stats(struct stats *stats)
 102 {
 103         return stats->mean;
 104 }
 105
 106 /*
 107  * http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance
 108  *
 109  *       (\Sum n_i^2) - ((\Sum n_i)^2)/n
 110  * s^2 = -------------------------------
 111  *                  n - 1
 112  *
 113  * http://en.wikipedia.org/wiki/Stddev
 114  *
 115  * The std dev of the mean is related to the std dev by:
 116  *
 117  *             s
 118  * s_mean = -------
 119  *          sqrt(n)
 120  *
 121  */
 122 static double stddev_stats(struct stats *stats)
 123 {
 124         double variance = stats->M2 / (stats->n - 1);
 125         double variance_mean = variance / stats->n;
 126
 127         return sqrt(variance_mean);
 128 }
 129
 130 struct stats                    event_res_stats[MAX_COUNTERS][3];
 131 struct stats                    runtime_nsecs_stats;
 132 struct stats                    walltime_nsecs_stats;
 133 struct stats                    runtime_cycles_stats;
 134 struct stats                    runtime_branches_stats;
 135
 136 #define MATCH_EVENT(t, c, counter)                      \
 137         (attrs[counter].type == PERF_TYPE_##t &&        \
 138          attrs[counter].config == PERF_COUNT_##c)
 139
 140 #define ERR_PERF_OPEN \
 141 "Error: counter %d, sys_perf_event_open() syscall returned with %d (%s)\n"
 142
 143 static void create_perf_stat_counter(int counter, int pid)
 144 {
 145         struct perf_event_attr *attr = attrs + counter;
 146
 147         if (scale)
 148                 attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
 149                                     PERF_FORMAT_TOTAL_TIME_RUNNING;
 150
 151         if (system_wide) {
 152                 unsigned int cpu;
 153
 154                 for (cpu = 0; cpu < nr_cpus; cpu++) {
 155                         fd[cpu][counter] = sys_perf_event_open(attr, -1, cpumap[cpu], -1, 0);
 156                         if (fd[cpu][counter] < 0 && verbose)
 157                                 fprintf(stderr, ERR_PERF_OPEN, counter,
 158                                         fd[cpu][counter], strerror(errno));
 159                 }
 160         } else {
 161                 attr->inherit        = inherit;
 162                 attr->disabled       = 1;
 163                 attr->enable_on_exec = 1;
 164
 165                 fd[0][counter] = sys_perf_event_open(attr, pid, -1, -1, 0);
 166                 if (fd[0][counter] < 0 && verbose)
 167                         fprintf(stderr, ERR_PERF_OPEN, counter,
 168                                 fd[0][counter], strerror(errno));
 169         }
 170 }
 171
 172 /*
 173  * Does the counter have nsecs as a unit?
 174  */
 175 static inline int nsec_counter(int counter)
 176 {
 177         if (MATCH_EVENT(SOFTWARE, SW_CPU_CLOCK, counter) ||
 178             MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter))
 179                 return 1;
 180
 181         return 0;
 182 }
 183
 184 /*
 185  * Read out the results of a single counter:
 186  */
 187 static void read_counter(int counter)
 188 {
 189         u64 count[3], single_count[3];
 190         unsigned int cpu;
 191         size_t res, nv;
 192         int scaled;
 193         int i;
 194
 195         count[0] = count[1] = count[2] = 0;
 196
 197         nv = scale ? 3 : 1;
 198         for (cpu = 0; cpu < nr_cpus; cpu++) {
 199                 if (fd[cpu][counter] < 0)
 200                         continue;
 201
 202                 res = read(fd[cpu][counter], single_count, nv * sizeof(u64));
 203                 assert(res == nv * sizeof(u64));
 204
 205                 close(fd[cpu][counter]);
 206                 fd[cpu][counter] = -1;
 207
 208                 count[0] += single_count[0];
 209                 if (scale) {
 210                         count[1] += single_count[1];
 211                         count[2] += single_count[2];
 212                 }
 213         }
 214
 215         scaled = 0;
 216         if (scale) {
 217                 if (count[2] == 0) {
 218                         event_scaled[counter] = -1;
 219                         count[0] = 0;
 220                         return;
 221                 }
 222
 223                 if (count[2] < count[1]) {
 224                         event_scaled[counter] = 1;
 225                         count[0] = (unsigned long long)
 226                                 ((double)count[0] * count[1] / count[2] + 0.5);
 227                 }
 228         }
 229
 230         for (i = 0; i < 3; i++)
 231                 update_stats(&event_res_stats[counter][i], count[i]);
 232
 233         if (verbose) {
 234                 fprintf(stderr, "%s: %Ld %Ld %Ld\n", event_name(counter),
 235                                 count[0], count[1], count[2]);
 236         }
 237
 238         /*
 239          * Save the full runtime - to allow normalization during printout:
 240          */
 241         if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter))
 242                 update_stats(&runtime_nsecs_stats, count[0]);
 243         if (MATCH_EVENT(HARDWARE, HW_CPU_CYCLES, counter))
 244                 update_stats(&runtime_cycles_stats, count[0]);
 245         if (MATCH_EVENT(HARDWARE, HW_BRANCH_INSTRUCTIONS, counter))
 246                 update_stats(&runtime_branches_stats, count[0]);
 247 }
 248
 249 static int run_perf_stat(int argc __used, const char **argv)
 250 {
 251         unsigned long long t0, t1;
 252         int status = 0;
 253         int counter;
 254         int pid = target_pid;
 255         int child_ready_pipe[2], go_pipe[2];
 256         const bool forks = (target_pid == -1 && argc > 0);
 257         char buf;
 258
 259         if (!system_wide)
 260                 nr_cpus = 1;
 261
 262         if (forks && (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) {
 263                 perror("failed to create pipes");
 264                 exit(1);
 265         }
 266
 267         if (forks) {
 268                 if ((pid = fork()) < 0)
 269                         perror("failed to fork");
 270
 271                 if (!pid) {
 272                         close(child_ready_pipe[0]);
 273                         close(go_pipe[1]);
 274                         fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC);
 275
 276                         /*
 277                          * Do a dummy execvp to get the PLT entry resolved,
 278                          * so we avoid the resolver overhead on the real
 279                          * execvp call.
 280                          */
 281                         execvp("", (char **)argv);
 282
 283                         /*
 284                          * Tell the parent we're ready to go
 285                          */
 286                         close(child_ready_pipe[1]);
 287
 288                         /*
 289                          * Wait until the parent tells us to go.
 290                          */
 291                         if (read(go_pipe[0], &buf, 1) == -1)
 292                                 perror("unable to read pipe");
 293
 294                         execvp(argv[0], (char **)argv);
 295
 296                         perror(argv[0]);
 297                         exit(-1);
 298                 }
 299
 300                 child_pid = pid;
 301
 302                 /*
 303                  * Wait for the child to be ready to exec.
 304                  */
 305                 close(child_ready_pipe[1]);
 306                 close(go_pipe[0]);
 307                 if (read(child_ready_pipe[0], &buf, 1) == -1)
 308                         perror("unable to read pipe");
 309                 close(child_ready_pipe[0]);
 310         }
 311
 312         for (counter = 0; counter < nr_counters; counter++)
 313                 create_perf_stat_counter(counter, pid);
 314
 315         /*
 316          * Enable counters and exec the command:
 317          */
 318         t0 = rdclock();
 319
 320         if (forks) {
 321                 close(go_pipe[1]);
 322                 wait(&status);
 323         } else {
 324                 while(!done);
 325         }
 326
 327         t1 = rdclock();
 328
 329         update_stats(&walltime_nsecs_stats, t1 - t0);
 330
 331         for (counter = 0; counter < nr_counters; counter++)
 332                 read_counter(counter);
 333
 334         return WEXITSTATUS(status);
 335 }
 336
 337 static void print_noise(int counter, double avg)
 338 {
 339         if (run_count == 1)
 340                 return;
 341
 342         fprintf(stderr, "   ( +- %7.3f%% )",
 343                         100 * stddev_stats(&event_res_stats[counter][0]) / avg);
 344 }
 345
 346 static void nsec_printout(int counter, double avg)
 347 {
 348         double msecs = avg / 1e6;
 349
 350         fprintf(stderr, " %14.6f  %-24s", msecs, event_name(counter));
 351
 352         if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) {
 353                 fprintf(stderr, " # %10.3f CPUs ",
 354                                 avg / avg_stats(&walltime_nsecs_stats));
 355         }
 356 }
 357
 358 static void abs_printout(int counter, double avg)
 359 {
 360         double total, ratio = 0.0;
 361
 362         fprintf(stderr, " %14.0f  %-24s", avg, event_name(counter));
 363
 364         if (MATCH_EVENT(HARDWARE, HW_INSTRUCTIONS, counter)) {
 365                 total = avg_stats(&runtime_cycles_stats);
 366
 367                 if (total)
 368                         ratio = avg / total;
 369
 370                 fprintf(stderr, " # %10.3f IPC  ", ratio);
 371         } else if (MATCH_EVENT(HARDWARE, HW_BRANCH_MISSES, counter) &&
 372                         runtime_branches_stats.n != 0) {
 373                 total = avg_stats(&runtime_branches_stats);
 374
 375                 if (total)
 376                         ratio = avg * 100 / total;
 377
 378                 fprintf(stderr, " # %10.3f %%    ", ratio);
 379
 380         } else if (runtime_nsecs_stats.n != 0) {
 381                 total = avg_stats(&runtime_nsecs_stats);
 382
 383                 if (total)
 384                         ratio = 1000.0 * avg / total;
 385
 386                 fprintf(stderr, " # %10.3f M/sec", ratio);
 387         }
 388 }
 389
 390 /*
 391  * Print out the results of a single counter:
 392  */
 393 static void print_counter(int counter)
 394 {
 395         double avg = avg_stats(&event_res_stats[counter][0]);
 396         int scaled = event_scaled[counter];
 397
 398         if (scaled == -1) {
 399                 fprintf(stderr, " %14s  %-24s\n",
 400                         "<not counted>", event_name(counter));
 401                 return;
 402         }
 403
 404         if (nsec_counter(counter))
 405                 nsec_printout(counter, avg);
 406         else
 407                 abs_printout(counter, avg);
 408
 409         print_noise(counter, avg);
 410
 411         if (scaled) {
 412                 double avg_enabled, avg_running;
 413
 414                 avg_enabled = avg_stats(&event_res_stats[counter][1]);
 415                 avg_running = avg_stats(&event_res_stats[counter][2]);
 416
 417                 fprintf(stderr, "  (scaled from %.2f%%)",
 418                                 100 * avg_running / avg_enabled);
 419         }
 420
 421         fprintf(stderr, "\n");
 422 }
 423
 424 static void print_stat(int argc, const char **argv)
 425 {
 426         int i, counter;
 427
 428         fflush(stdout);
 429
 430         fprintf(stderr, "\n");
 431         fprintf(stderr, " Performance counter stats for ");
 432         if(target_pid == -1) {
 433                 fprintf(stderr, "\'%s", argv[0]);
 434                 for (i = 1; i < argc; i++)
 435                         fprintf(stderr, " %s", argv[i]);
 436         }else
 437                 fprintf(stderr, "task pid \'%d", target_pid);
 438
 439         fprintf(stderr, "\'");
 440         if (run_count > 1)
 441                 fprintf(stderr, " (%d runs)", run_count);
 442         fprintf(stderr, ":\n\n");
 443
 444         for (counter = 0; counter < nr_counters; counter++)
 445                 print_counter(counter);
 446
 447         fprintf(stderr, "\n");
 448         fprintf(stderr, " %14.9f  seconds time elapsed",
 449                         avg_stats(&walltime_nsecs_stats)/1e9);
 450         if (run_count > 1) {
 451                 fprintf(stderr, "   ( +- %7.3f%% )",
 452                                 100*stddev_stats(&walltime_nsecs_stats) /
 453                                 avg_stats(&walltime_nsecs_stats));
 454         }
 455         fprintf(stderr, "\n\n");
 456 }
 457
 458 static volatile int signr = -1;
 459
 460 static void skip_signal(int signo)
 461 {
 462         if(target_pid != -1)
 463                 done = 1;
 464
 465         signr = signo;
 466 }
 467
 468 static void sig_atexit(void)
 469 {
 470         if (child_pid != -1)
 471                 kill(child_pid, SIGTERM);
 472
 473         if (signr == -1)
 474                 return;
 475
 476         signal(signr, SIG_DFL);
 477         kill(getpid(), signr);
 478 }
 479
 480 static const char * const stat_usage[] = {
 481         "perf stat [<options>] [<command>]",
 482         NULL
 483 };
 484
 485 static const struct option options[] = {
 486         OPT_CALLBACK('e', "event", NULL, "event",
 487                      "event selector. use 'perf list' to list available events",
 488                      parse_events),
 489         OPT_BOOLEAN('i', "inherit", &inherit,
 490                     "child tasks inherit counters"),
 491         OPT_INTEGER('p', "pid", &target_pid,
 492                     "stat events on existing pid"),
 493         OPT_BOOLEAN('a', "all-cpus", &system_wide,
 494                     "system-wide collection from all CPUs"),
 495         OPT_BOOLEAN('c', "scale", &scale,
 496                     "scale/normalize counters"),
 497         OPT_BOOLEAN('v', "verbose", &verbose,
 498                     "be more verbose (show counter open errors, etc)"),
 499         OPT_INTEGER('r', "repeat", &run_count,
 500                     "repeat command and print average + stddev (max: 100)"),
 501         OPT_BOOLEAN('n', "null", &null_run,
 502                     "null run - dont start any counters"),
 503         OPT_END()
 504 };
 505
 506 int cmd_stat(int argc, const char **argv, const char *prefix __used)
 507 {
 508         int status;
 509
 510         argc = parse_options(argc, argv, options, stat_usage,
 511                 PARSE_OPT_STOP_AT_NON_OPTION);
 512         if (!argc && target_pid == -1)
 513                 usage_with_options(stat_usage, options);
 514         if (run_count <= 0)
 515                 usage_with_options(stat_usage, options);
 516
 517         /* Set attrs and nr_counters if no event is selected and !null_run */
 518         if (!null_run && !nr_counters) {
 519                 memcpy(attrs, default_attrs, sizeof(default_attrs));
 520                 nr_counters = ARRAY_SIZE(default_attrs);
 521         }
 522
 523         if (system_wide)
 524                 nr_cpus = read_cpu_map();
 525         else
 526                 nr_cpus = 1;
 527
 528         /*
 529          * We dont want to block the signals - that would cause
 530          * child tasks to inherit that and Ctrl-C would not work.
 531          * What we want is for Ctrl-C to work in the exec()-ed
 532          * task, but being ignored by perf stat itself:
 533          */
 534         atexit(sig_atexit);
 535         signal(SIGINT,  skip_signal);
 536         signal(SIGALRM, skip_signal);
 537         signal(SIGABRT, skip_signal);
 538
 539         status = 0;
 540         for (run_idx = 0; run_idx < run_count; run_idx++) {
 541                 if (run_count != 1 && verbose)
 542                         fprintf(stderr, "[ perf stat: executing run #%d ... ]\n", run_idx + 1);
 543                 status = run_perf_stat(argc, argv);
 544         }
 545
 546         print_stat(argc, argv);
 547
 548         return status;
 549 }