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 #include "util/thread.h" 50 51 #include <sys/prctl.h> 52 #include <math.h> 53 #include <locale.h> 54 55 static struct perf_event_attr default_attrs[] = { 56 57 { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_TASK_CLOCK }, 58 { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CONTEXT_SWITCHES }, 59 { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_MIGRATIONS }, 60 { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_PAGE_FAULTS }, 61 62 { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES }, 63 { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_INSTRUCTIONS }, 64 { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS }, 65 { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_MISSES }, 66 { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_REFERENCES }, 67 { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_MISSES }, 68 69 }; 70 71 static bool system_wide = false; 72 static int nr_cpus = 0; 73 static int run_idx = 0; 74 75 static int run_count = 1; 76 static bool no_inherit = false; 77 static bool scale = true; 78 static pid_t target_pid = -1; 79 static pid_t target_tid = -1; 80 static pid_t *all_tids = NULL; 81 static int thread_num = 0; 82 static pid_t child_pid = -1; 83 static bool null_run = false; 84 static bool big_num = false; 85 static const char *cpu_list; 86 87 88 static int *fd[MAX_NR_CPUS][MAX_COUNTERS]; 89 90 static int event_scaled[MAX_COUNTERS]; 91 92 static volatile int done = 0; 93 94 struct stats 95 { 96 double n, mean, M2; 97 }; 98 99 static void update_stats(struct stats *stats, u64 val) 100 { 101 double delta; 102 103 stats->n++; 104 delta = val - stats->mean; 105 stats->mean += delta / stats->n; 106 stats->M2 += delta*(val - stats->mean); 107 } 108 109 static double avg_stats(struct stats *stats) 110 { 111 return stats->mean; 112 } 113 114 /* 115 * http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance 116 * 117 * (\Sum n_i^2) - ((\Sum n_i)^2)/n 118 * s^2 = ------------------------------- 119 * n - 1 120 * 121 * http://en.wikipedia.org/wiki/Stddev 122 * 123 * The std dev of the mean is related to the std dev by: 124 * 125 * s 126 * s_mean = ------- 127 * sqrt(n) 128 * 129 */ 130 static double stddev_stats(struct stats *stats) 131 { 132 double variance = stats->M2 / (stats->n - 1); 133 double variance_mean = variance / stats->n; 134 135 return sqrt(variance_mean); 136 } 137 138 struct stats event_res_stats[MAX_COUNTERS][3]; 139 struct stats runtime_nsecs_stats; 140 struct stats walltime_nsecs_stats; 141 struct stats runtime_cycles_stats; 142 struct stats runtime_branches_stats; 143 144 #define MATCH_EVENT(t, c, counter) \ 145 (attrs[counter].type == PERF_TYPE_##t && \ 146 attrs[counter].config == PERF_COUNT_##c) 147 148 #define ERR_PERF_OPEN \ 149 "Error: counter %d, sys_perf_event_open() syscall returned with %d (%s)\n" 150 151 static int create_perf_stat_counter(int counter) 152 { 153 struct perf_event_attr *attr = attrs + counter; 154 int thread; 155 int ncreated = 0; 156 157 if (scale) 158 attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED | 159 PERF_FORMAT_TOTAL_TIME_RUNNING; 160 161 if (system_wide) { 162 int cpu; 163 164 for (cpu = 0; cpu < nr_cpus; cpu++) { 165 fd[cpu][counter][0] = sys_perf_event_open(attr, 166 -1, cpumap[cpu], -1, 0); 167 if (fd[cpu][counter][0] < 0) 168 pr_debug(ERR_PERF_OPEN, counter, 169 fd[cpu][counter][0], strerror(errno)); 170 else 171 ++ncreated; 172 } 173 } else { 174 attr->inherit = !no_inherit; 175 if (target_pid == -1 && target_tid == -1) { 176 attr->disabled = 1; 177 attr->enable_on_exec = 1; 178 } 179 for (thread = 0; thread < thread_num; thread++) { 180 fd[0][counter][thread] = sys_perf_event_open(attr, 181 all_tids[thread], -1, -1, 0); 182 if (fd[0][counter][thread] < 0) 183 pr_debug(ERR_PERF_OPEN, counter, 184 fd[0][counter][thread], 185 strerror(errno)); 186 else 187 ++ncreated; 188 } 189 } 190 191 return ncreated; 192 } 193 194 /* 195 * Does the counter have nsecs as a unit? 196 */ 197 static inline int nsec_counter(int counter) 198 { 199 if (MATCH_EVENT(SOFTWARE, SW_CPU_CLOCK, counter) || 200 MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) 201 return 1; 202 203 return 0; 204 } 205 206 /* 207 * Read out the results of a single counter: 208 */ 209 static void read_counter(int counter) 210 { 211 u64 count[3], single_count[3]; 212 int cpu; 213 size_t res, nv; 214 int scaled; 215 int i, thread; 216 217 count[0] = count[1] = count[2] = 0; 218 219 nv = scale ? 3 : 1; 220 for (cpu = 0; cpu < nr_cpus; cpu++) { 221 for (thread = 0; thread < thread_num; thread++) { 222 if (fd[cpu][counter][thread] < 0) 223 continue; 224 225 res = read(fd[cpu][counter][thread], 226 single_count, nv * sizeof(u64)); 227 assert(res == nv * sizeof(u64)); 228 229 close(fd[cpu][counter][thread]); 230 fd[cpu][counter][thread] = -1; 231 232 count[0] += single_count[0]; 233 if (scale) { 234 count[1] += single_count[1]; 235 count[2] += single_count[2]; 236 } 237 } 238 } 239 240 scaled = 0; 241 if (scale) { 242 if (count[2] == 0) { 243 event_scaled[counter] = -1; 244 count[0] = 0; 245 return; 246 } 247 248 if (count[2] < count[1]) { 249 event_scaled[counter] = 1; 250 count[0] = (unsigned long long) 251 ((double)count[0] * count[1] / count[2] + 0.5); 252 } 253 } 254 255 for (i = 0; i < 3; i++) 256 update_stats(&event_res_stats[counter][i], count[i]); 257 258 if (verbose) { 259 fprintf(stderr, "%s: %Ld %Ld %Ld\n", event_name(counter), 260 count[0], count[1], count[2]); 261 } 262 263 /* 264 * Save the full runtime - to allow normalization during printout: 265 */ 266 if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) 267 update_stats(&runtime_nsecs_stats, count[0]); 268 if (MATCH_EVENT(HARDWARE, HW_CPU_CYCLES, counter)) 269 update_stats(&runtime_cycles_stats, count[0]); 270 if (MATCH_EVENT(HARDWARE, HW_BRANCH_INSTRUCTIONS, counter)) 271 update_stats(&runtime_branches_stats, count[0]); 272 } 273 274 static int run_perf_stat(int argc __used, const char **argv) 275 { 276 unsigned long long t0, t1; 277 int status = 0; 278 int counter, ncreated = 0; 279 int child_ready_pipe[2], go_pipe[2]; 280 const bool forks = (argc > 0); 281 char buf; 282 283 if (!system_wide) 284 nr_cpus = 1; 285 286 if (forks && (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) { 287 perror("failed to create pipes"); 288 exit(1); 289 } 290 291 if (forks) { 292 if ((child_pid = fork()) < 0) 293 perror("failed to fork"); 294 295 if (!child_pid) { 296 close(child_ready_pipe[0]); 297 close(go_pipe[1]); 298 fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC); 299 300 /* 301 * Do a dummy execvp to get the PLT entry resolved, 302 * so we avoid the resolver overhead on the real 303 * execvp call. 304 */ 305 execvp("", (char **)argv); 306 307 /* 308 * Tell the parent we're ready to go 309 */ 310 close(child_ready_pipe[1]); 311 312 /* 313 * Wait until the parent tells us to go. 314 */ 315 if (read(go_pipe[0], &buf, 1) == -1) 316 perror("unable to read pipe"); 317 318 execvp(argv[0], (char **)argv); 319 320 perror(argv[0]); 321 exit(-1); 322 } 323 324 if (target_tid == -1 && target_pid == -1 && !system_wide) 325 all_tids[0] = child_pid; 326 327 /* 328 * Wait for the child to be ready to exec. 329 */ 330 close(child_ready_pipe[1]); 331 close(go_pipe[0]); 332 if (read(child_ready_pipe[0], &buf, 1) == -1) 333 perror("unable to read pipe"); 334 close(child_ready_pipe[0]); 335 } 336 337 for (counter = 0; counter < nr_counters; counter++) 338 ncreated += create_perf_stat_counter(counter); 339 340 if (ncreated == 0) { 341 pr_err("No permission to collect %sstats.\n" 342 "Consider tweaking /proc/sys/kernel/perf_event_paranoid.\n", 343 system_wide ? "system-wide " : ""); 344 if (child_pid != -1) 345 kill(child_pid, SIGTERM); 346 return -1; 347 } 348 349 /* 350 * Enable counters and exec the command: 351 */ 352 t0 = rdclock(); 353 354 if (forks) { 355 close(go_pipe[1]); 356 wait(&status); 357 } else { 358 while(!done) sleep(1); 359 } 360 361 t1 = rdclock(); 362 363 update_stats(&walltime_nsecs_stats, t1 - t0); 364 365 for (counter = 0; counter < nr_counters; counter++) 366 read_counter(counter); 367 368 return WEXITSTATUS(status); 369 } 370 371 static void print_noise(int counter, double avg) 372 { 373 if (run_count == 1) 374 return; 375 376 fprintf(stderr, " ( +- %7.3f%% )", 377 100 * stddev_stats(&event_res_stats[counter][0]) / avg); 378 } 379 380 static void nsec_printout(int counter, double avg) 381 { 382 double msecs = avg / 1e6; 383 384 fprintf(stderr, " %18.6f %-24s", msecs, event_name(counter)); 385 386 if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) { 387 fprintf(stderr, " # %10.3f CPUs ", 388 avg / avg_stats(&walltime_nsecs_stats)); 389 } 390 } 391 392 static void abs_printout(int counter, double avg) 393 { 394 double total, ratio = 0.0; 395 396 if (big_num) 397 fprintf(stderr, " %'18.0f %-24s", avg, event_name(counter)); 398 else 399 fprintf(stderr, " %18.0f %-24s", avg, event_name(counter)); 400 401 if (MATCH_EVENT(HARDWARE, HW_INSTRUCTIONS, counter)) { 402 total = avg_stats(&runtime_cycles_stats); 403 404 if (total) 405 ratio = avg / total; 406 407 fprintf(stderr, " # %10.3f IPC ", ratio); 408 } else if (MATCH_EVENT(HARDWARE, HW_BRANCH_MISSES, counter) && 409 runtime_branches_stats.n != 0) { 410 total = avg_stats(&runtime_branches_stats); 411 412 if (total) 413 ratio = avg * 100 / total; 414 415 fprintf(stderr, " # %10.3f %% ", ratio); 416 417 } else if (runtime_nsecs_stats.n != 0) { 418 total = avg_stats(&runtime_nsecs_stats); 419 420 if (total) 421 ratio = 1000.0 * avg / total; 422 423 fprintf(stderr, " # %10.3f M/sec", ratio); 424 } 425 } 426 427 /* 428 * Print out the results of a single counter: 429 */ 430 static void print_counter(int counter) 431 { 432 double avg = avg_stats(&event_res_stats[counter][0]); 433 int scaled = event_scaled[counter]; 434 435 if (scaled == -1) { 436 fprintf(stderr, " %18s %-24s\n", 437 "<not counted>", event_name(counter)); 438 return; 439 } 440 441 if (nsec_counter(counter)) 442 nsec_printout(counter, avg); 443 else 444 abs_printout(counter, avg); 445 446 print_noise(counter, avg); 447 448 if (scaled) { 449 double avg_enabled, avg_running; 450 451 avg_enabled = avg_stats(&event_res_stats[counter][1]); 452 avg_running = avg_stats(&event_res_stats[counter][2]); 453 454 fprintf(stderr, " (scaled from %.2f%%)", 455 100 * avg_running / avg_enabled); 456 } 457 458 fprintf(stderr, "\n"); 459 } 460 461 static void print_stat(int argc, const char **argv) 462 { 463 int i, counter; 464 465 fflush(stdout); 466 467 fprintf(stderr, "\n"); 468 fprintf(stderr, " Performance counter stats for "); 469 if(target_pid == -1 && target_tid == -1) { 470 fprintf(stderr, "\'%s", argv[0]); 471 for (i = 1; i < argc; i++) 472 fprintf(stderr, " %s", argv[i]); 473 } else if (target_pid != -1) 474 fprintf(stderr, "process id \'%d", target_pid); 475 else 476 fprintf(stderr, "thread id \'%d", target_tid); 477 478 fprintf(stderr, "\'"); 479 if (run_count > 1) 480 fprintf(stderr, " (%d runs)", run_count); 481 fprintf(stderr, ":\n\n"); 482 483 for (counter = 0; counter < nr_counters; counter++) 484 print_counter(counter); 485 486 fprintf(stderr, "\n"); 487 fprintf(stderr, " %18.9f seconds time elapsed", 488 avg_stats(&walltime_nsecs_stats)/1e9); 489 if (run_count > 1) { 490 fprintf(stderr, " ( +- %7.3f%% )", 491 100*stddev_stats(&walltime_nsecs_stats) / 492 avg_stats(&walltime_nsecs_stats)); 493 } 494 fprintf(stderr, "\n\n"); 495 } 496 497 static volatile int signr = -1; 498 499 static void skip_signal(int signo) 500 { 501 if(child_pid == -1) 502 done = 1; 503 504 signr = signo; 505 } 506 507 static void sig_atexit(void) 508 { 509 if (child_pid != -1) 510 kill(child_pid, SIGTERM); 511 512 if (signr == -1) 513 return; 514 515 signal(signr, SIG_DFL); 516 kill(getpid(), signr); 517 } 518 519 static const char * const stat_usage[] = { 520 "perf stat [<options>] [<command>]", 521 NULL 522 }; 523 524 static const struct option options[] = { 525 OPT_CALLBACK('e', "event", NULL, "event", 526 "event selector. use 'perf list' to list available events", 527 parse_events), 528 OPT_BOOLEAN('i', "no-inherit", &no_inherit, 529 "child tasks do not inherit counters"), 530 OPT_INTEGER('p', "pid", &target_pid, 531 "stat events on existing process id"), 532 OPT_INTEGER('t', "tid", &target_tid, 533 "stat events on existing thread id"), 534 OPT_BOOLEAN('a', "all-cpus", &system_wide, 535 "system-wide collection from all CPUs"), 536 OPT_BOOLEAN('c', "scale", &scale, 537 "scale/normalize counters"), 538 OPT_INCR('v', "verbose", &verbose, 539 "be more verbose (show counter open errors, etc)"), 540 OPT_INTEGER('r', "repeat", &run_count, 541 "repeat command and print average + stddev (max: 100)"), 542 OPT_BOOLEAN('n', "null", &null_run, 543 "null run - dont start any counters"), 544 OPT_BOOLEAN('B', "big-num", &big_num, 545 "print large numbers with thousands\' separators"), 546 OPT_STRING('C', "cpu", &cpu_list, "cpu", 547 "list of cpus to monitor in system-wide"), 548 OPT_END() 549 }; 550 551 int cmd_stat(int argc, const char **argv, const char *prefix __used) 552 { 553 int status; 554 int i,j; 555 556 setlocale(LC_ALL, ""); 557 558 argc = parse_options(argc, argv, options, stat_usage, 559 PARSE_OPT_STOP_AT_NON_OPTION); 560 if (!argc && target_pid == -1 && target_tid == -1) 561 usage_with_options(stat_usage, options); 562 if (run_count <= 0) 563 usage_with_options(stat_usage, options); 564 565 /* Set attrs and nr_counters if no event is selected and !null_run */ 566 if (!null_run && !nr_counters) { 567 memcpy(attrs, default_attrs, sizeof(default_attrs)); 568 nr_counters = ARRAY_SIZE(default_attrs); 569 } 570 571 if (system_wide) 572 nr_cpus = read_cpu_map(cpu_list); 573 else 574 nr_cpus = 1; 575 576 if (nr_cpus < 1) 577 usage_with_options(stat_usage, options); 578 579 if (target_pid != -1) { 580 target_tid = target_pid; 581 thread_num = find_all_tid(target_pid, &all_tids); 582 if (thread_num <= 0) { 583 fprintf(stderr, "Can't find all threads of pid %d\n", 584 target_pid); 585 usage_with_options(stat_usage, options); 586 } 587 } else { 588 all_tids=malloc(sizeof(pid_t)); 589 if (!all_tids) 590 return -ENOMEM; 591 592 all_tids[0] = target_tid; 593 thread_num = 1; 594 } 595 596 for (i = 0; i < MAX_NR_CPUS; i++) { 597 for (j = 0; j < MAX_COUNTERS; j++) { 598 fd[i][j] = malloc(sizeof(int)*thread_num); 599 if (!fd[i][j]) 600 return -ENOMEM; 601 } 602 } 603 604 /* 605 * We dont want to block the signals - that would cause 606 * child tasks to inherit that and Ctrl-C would not work. 607 * What we want is for Ctrl-C to work in the exec()-ed 608 * task, but being ignored by perf stat itself: 609 */ 610 atexit(sig_atexit); 611 signal(SIGINT, skip_signal); 612 signal(SIGALRM, skip_signal); 613 signal(SIGABRT, skip_signal); 614 615 status = 0; 616 for (run_idx = 0; run_idx < run_count; run_idx++) { 617 if (run_count != 1 && verbose) 618 fprintf(stderr, "[ perf stat: executing run #%d ... ]\n", run_idx + 1); 619 status = run_perf_stat(argc, argv); 620 } 621 622 if (status != -1) 623 print_stat(argc, argv); 624 625 return status; 626 } 627