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 54 static struct perf_event_attr default_attrs[] = { 55 56 { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_TASK_CLOCK }, 57 { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CONTEXT_SWITCHES }, 58 { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_CPU_MIGRATIONS }, 59 { .type = PERF_TYPE_SOFTWARE, .config = PERF_COUNT_SW_PAGE_FAULTS }, 60 61 { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES }, 62 { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_INSTRUCTIONS }, 63 { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS }, 64 { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_BRANCH_MISSES }, 65 { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_REFERENCES }, 66 { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CACHE_MISSES }, 67 68 }; 69 70 static bool system_wide = false; 71 static unsigned int nr_cpus = 0; 72 static int run_idx = 0; 73 74 static int run_count = 1; 75 static bool no_inherit = false; 76 static bool scale = true; 77 static pid_t target_pid = -1; 78 static pid_t target_tid = -1; 79 static pid_t *all_tids = NULL; 80 static int thread_num = 0; 81 static pid_t child_pid = -1; 82 static bool null_run = false; 83 84 static int *fd[MAX_NR_CPUS][MAX_COUNTERS]; 85 86 static int event_scaled[MAX_COUNTERS]; 87 88 static volatile int done = 0; 89 90 struct stats 91 { 92 double n, mean, M2; 93 }; 94 95 static void update_stats(struct stats *stats, u64 val) 96 { 97 double delta; 98 99 stats->n++; 100 delta = val - stats->mean; 101 stats->mean += delta / stats->n; 102 stats->M2 += delta*(val - stats->mean); 103 } 104 105 static double avg_stats(struct stats *stats) 106 { 107 return stats->mean; 108 } 109 110 /* 111 * http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance 112 * 113 * (\Sum n_i^2) - ((\Sum n_i)^2)/n 114 * s^2 = ------------------------------- 115 * n - 1 116 * 117 * http://en.wikipedia.org/wiki/Stddev 118 * 119 * The std dev of the mean is related to the std dev by: 120 * 121 * s 122 * s_mean = ------- 123 * sqrt(n) 124 * 125 */ 126 static double stddev_stats(struct stats *stats) 127 { 128 double variance = stats->M2 / (stats->n - 1); 129 double variance_mean = variance / stats->n; 130 131 return sqrt(variance_mean); 132 } 133 134 struct stats event_res_stats[MAX_COUNTERS][3]; 135 struct stats runtime_nsecs_stats; 136 struct stats walltime_nsecs_stats; 137 struct stats runtime_cycles_stats; 138 struct stats runtime_branches_stats; 139 140 #define MATCH_EVENT(t, c, counter) \ 141 (attrs[counter].type == PERF_TYPE_##t && \ 142 attrs[counter].config == PERF_COUNT_##c) 143 144 #define ERR_PERF_OPEN \ 145 "Error: counter %d, sys_perf_event_open() syscall returned with %d (%s)\n" 146 147 static int create_perf_stat_counter(int counter) 148 { 149 struct perf_event_attr *attr = attrs + counter; 150 int thread; 151 int ncreated = 0; 152 153 if (scale) 154 attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED | 155 PERF_FORMAT_TOTAL_TIME_RUNNING; 156 157 if (system_wide) { 158 unsigned int cpu; 159 160 for (cpu = 0; cpu < nr_cpus; cpu++) { 161 fd[cpu][counter][0] = sys_perf_event_open(attr, 162 -1, cpumap[cpu], -1, 0); 163 if (fd[cpu][counter][0] < 0) 164 pr_debug(ERR_PERF_OPEN, counter, 165 fd[cpu][counter][0], strerror(errno)); 166 else 167 ++ncreated; 168 } 169 } else { 170 attr->inherit = !no_inherit; 171 if (target_pid == -1 && target_tid == -1) { 172 attr->disabled = 1; 173 attr->enable_on_exec = 1; 174 } 175 for (thread = 0; thread < thread_num; thread++) { 176 fd[0][counter][thread] = sys_perf_event_open(attr, 177 all_tids[thread], -1, -1, 0); 178 if (fd[0][counter][thread] < 0) 179 pr_debug(ERR_PERF_OPEN, counter, 180 fd[0][counter][thread], 181 strerror(errno)); 182 else 183 ++ncreated; 184 } 185 } 186 187 return ncreated; 188 } 189 190 /* 191 * Does the counter have nsecs as a unit? 192 */ 193 static inline int nsec_counter(int counter) 194 { 195 if (MATCH_EVENT(SOFTWARE, SW_CPU_CLOCK, counter) || 196 MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) 197 return 1; 198 199 return 0; 200 } 201 202 /* 203 * Read out the results of a single counter: 204 */ 205 static void read_counter(int counter) 206 { 207 u64 count[3], single_count[3]; 208 unsigned int cpu; 209 size_t res, nv; 210 int scaled; 211 int i, thread; 212 213 count[0] = count[1] = count[2] = 0; 214 215 nv = scale ? 3 : 1; 216 for (cpu = 0; cpu < nr_cpus; cpu++) { 217 for (thread = 0; thread < thread_num; thread++) { 218 if (fd[cpu][counter][thread] < 0) 219 continue; 220 221 res = read(fd[cpu][counter][thread], 222 single_count, nv * sizeof(u64)); 223 assert(res == nv * sizeof(u64)); 224 225 close(fd[cpu][counter][thread]); 226 fd[cpu][counter][thread] = -1; 227 228 count[0] += single_count[0]; 229 if (scale) { 230 count[1] += single_count[1]; 231 count[2] += single_count[2]; 232 } 233 } 234 } 235 236 scaled = 0; 237 if (scale) { 238 if (count[2] == 0) { 239 event_scaled[counter] = -1; 240 count[0] = 0; 241 return; 242 } 243 244 if (count[2] < count[1]) { 245 event_scaled[counter] = 1; 246 count[0] = (unsigned long long) 247 ((double)count[0] * count[1] / count[2] + 0.5); 248 } 249 } 250 251 for (i = 0; i < 3; i++) 252 update_stats(&event_res_stats[counter][i], count[i]); 253 254 if (verbose) { 255 fprintf(stderr, "%s: %Ld %Ld %Ld\n", event_name(counter), 256 count[0], count[1], count[2]); 257 } 258 259 /* 260 * Save the full runtime - to allow normalization during printout: 261 */ 262 if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) 263 update_stats(&runtime_nsecs_stats, count[0]); 264 if (MATCH_EVENT(HARDWARE, HW_CPU_CYCLES, counter)) 265 update_stats(&runtime_cycles_stats, count[0]); 266 if (MATCH_EVENT(HARDWARE, HW_BRANCH_INSTRUCTIONS, counter)) 267 update_stats(&runtime_branches_stats, count[0]); 268 } 269 270 static int run_perf_stat(int argc __used, const char **argv) 271 { 272 unsigned long long t0, t1; 273 int status = 0; 274 int counter, ncreated = 0; 275 int child_ready_pipe[2], go_pipe[2]; 276 const bool forks = (argc > 0); 277 char buf; 278 279 if (!system_wide) 280 nr_cpus = 1; 281 282 if (forks && (pipe(child_ready_pipe) < 0 || pipe(go_pipe) < 0)) { 283 perror("failed to create pipes"); 284 exit(1); 285 } 286 287 if (forks) { 288 if ((child_pid = fork()) < 0) 289 perror("failed to fork"); 290 291 if (!child_pid) { 292 close(child_ready_pipe[0]); 293 close(go_pipe[1]); 294 fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC); 295 296 /* 297 * Do a dummy execvp to get the PLT entry resolved, 298 * so we avoid the resolver overhead on the real 299 * execvp call. 300 */ 301 execvp("", (char **)argv); 302 303 /* 304 * Tell the parent we're ready to go 305 */ 306 close(child_ready_pipe[1]); 307 308 /* 309 * Wait until the parent tells us to go. 310 */ 311 if (read(go_pipe[0], &buf, 1) == -1) 312 perror("unable to read pipe"); 313 314 execvp(argv[0], (char **)argv); 315 316 perror(argv[0]); 317 exit(-1); 318 } 319 320 if (target_tid == -1 && target_pid == -1 && !system_wide) 321 all_tids[0] = child_pid; 322 323 /* 324 * Wait for the child to be ready to exec. 325 */ 326 close(child_ready_pipe[1]); 327 close(go_pipe[0]); 328 if (read(child_ready_pipe[0], &buf, 1) == -1) 329 perror("unable to read pipe"); 330 close(child_ready_pipe[0]); 331 } 332 333 for (counter = 0; counter < nr_counters; counter++) 334 ncreated += create_perf_stat_counter(counter); 335 336 if (ncreated == 0) { 337 pr_err("No permission to collect %sstats.\n" 338 "Consider tweaking /proc/sys/kernel/perf_event_paranoid.\n", 339 system_wide ? "system-wide " : ""); 340 if (child_pid != -1) 341 kill(child_pid, SIGTERM); 342 return -1; 343 } 344 345 /* 346 * Enable counters and exec the command: 347 */ 348 t0 = rdclock(); 349 350 if (forks) { 351 close(go_pipe[1]); 352 wait(&status); 353 } else { 354 while(!done) sleep(1); 355 } 356 357 t1 = rdclock(); 358 359 update_stats(&walltime_nsecs_stats, t1 - t0); 360 361 for (counter = 0; counter < nr_counters; counter++) 362 read_counter(counter); 363 364 return WEXITSTATUS(status); 365 } 366 367 static void print_noise(int counter, double avg) 368 { 369 if (run_count == 1) 370 return; 371 372 fprintf(stderr, " ( +- %7.3f%% )", 373 100 * stddev_stats(&event_res_stats[counter][0]) / avg); 374 } 375 376 static void nsec_printout(int counter, double avg) 377 { 378 double msecs = avg / 1e6; 379 380 fprintf(stderr, " %14.6f %-24s", msecs, event_name(counter)); 381 382 if (MATCH_EVENT(SOFTWARE, SW_TASK_CLOCK, counter)) { 383 fprintf(stderr, " # %10.3f CPUs ", 384 avg / avg_stats(&walltime_nsecs_stats)); 385 } 386 } 387 388 static void abs_printout(int counter, double avg) 389 { 390 double total, ratio = 0.0; 391 392 fprintf(stderr, " %14.0f %-24s", avg, event_name(counter)); 393 394 if (MATCH_EVENT(HARDWARE, HW_INSTRUCTIONS, counter)) { 395 total = avg_stats(&runtime_cycles_stats); 396 397 if (total) 398 ratio = avg / total; 399 400 fprintf(stderr, " # %10.3f IPC ", ratio); 401 } else if (MATCH_EVENT(HARDWARE, HW_BRANCH_MISSES, counter) && 402 runtime_branches_stats.n != 0) { 403 total = avg_stats(&runtime_branches_stats); 404 405 if (total) 406 ratio = avg * 100 / total; 407 408 fprintf(stderr, " # %10.3f %% ", ratio); 409 410 } else if (runtime_nsecs_stats.n != 0) { 411 total = avg_stats(&runtime_nsecs_stats); 412 413 if (total) 414 ratio = 1000.0 * avg / total; 415 416 fprintf(stderr, " # %10.3f M/sec", ratio); 417 } 418 } 419 420 /* 421 * Print out the results of a single counter: 422 */ 423 static void print_counter(int counter) 424 { 425 double avg = avg_stats(&event_res_stats[counter][0]); 426 int scaled = event_scaled[counter]; 427 428 if (scaled == -1) { 429 fprintf(stderr, " %14s %-24s\n", 430 "<not counted>", event_name(counter)); 431 return; 432 } 433 434 if (nsec_counter(counter)) 435 nsec_printout(counter, avg); 436 else 437 abs_printout(counter, avg); 438 439 print_noise(counter, avg); 440 441 if (scaled) { 442 double avg_enabled, avg_running; 443 444 avg_enabled = avg_stats(&event_res_stats[counter][1]); 445 avg_running = avg_stats(&event_res_stats[counter][2]); 446 447 fprintf(stderr, " (scaled from %.2f%%)", 448 100 * avg_running / avg_enabled); 449 } 450 451 fprintf(stderr, "\n"); 452 } 453 454 static void print_stat(int argc, const char **argv) 455 { 456 int i, counter; 457 458 fflush(stdout); 459 460 fprintf(stderr, "\n"); 461 fprintf(stderr, " Performance counter stats for "); 462 if(target_pid == -1 && target_tid == -1) { 463 fprintf(stderr, "\'%s", argv[0]); 464 for (i = 1; i < argc; i++) 465 fprintf(stderr, " %s", argv[i]); 466 } else if (target_pid != -1) 467 fprintf(stderr, "process id \'%d", target_pid); 468 else 469 fprintf(stderr, "thread id \'%d", target_tid); 470 471 fprintf(stderr, "\'"); 472 if (run_count > 1) 473 fprintf(stderr, " (%d runs)", run_count); 474 fprintf(stderr, ":\n\n"); 475 476 for (counter = 0; counter < nr_counters; counter++) 477 print_counter(counter); 478 479 fprintf(stderr, "\n"); 480 fprintf(stderr, " %14.9f seconds time elapsed", 481 avg_stats(&walltime_nsecs_stats)/1e9); 482 if (run_count > 1) { 483 fprintf(stderr, " ( +- %7.3f%% )", 484 100*stddev_stats(&walltime_nsecs_stats) / 485 avg_stats(&walltime_nsecs_stats)); 486 } 487 fprintf(stderr, "\n\n"); 488 } 489 490 static volatile int signr = -1; 491 492 static void skip_signal(int signo) 493 { 494 if(child_pid == -1) 495 done = 1; 496 497 signr = signo; 498 } 499 500 static void sig_atexit(void) 501 { 502 if (child_pid != -1) 503 kill(child_pid, SIGTERM); 504 505 if (signr == -1) 506 return; 507 508 signal(signr, SIG_DFL); 509 kill(getpid(), signr); 510 } 511 512 static const char * const stat_usage[] = { 513 "perf stat [<options>] [<command>]", 514 NULL 515 }; 516 517 static const struct option options[] = { 518 OPT_CALLBACK('e', "event", NULL, "event", 519 "event selector. use 'perf list' to list available events", 520 parse_events), 521 OPT_BOOLEAN('i', "no-inherit", &no_inherit, 522 "child tasks do not inherit counters"), 523 OPT_INTEGER('p', "pid", &target_pid, 524 "stat events on existing process id"), 525 OPT_INTEGER('t', "tid", &target_tid, 526 "stat events on existing thread id"), 527 OPT_BOOLEAN('a', "all-cpus", &system_wide, 528 "system-wide collection from all CPUs"), 529 OPT_BOOLEAN('c', "scale", &scale, 530 "scale/normalize counters"), 531 OPT_INCR('v', "verbose", &verbose, 532 "be more verbose (show counter open errors, etc)"), 533 OPT_INTEGER('r', "repeat", &run_count, 534 "repeat command and print average + stddev (max: 100)"), 535 OPT_BOOLEAN('n', "null", &null_run, 536 "null run - dont start any counters"), 537 OPT_END() 538 }; 539 540 int cmd_stat(int argc, const char **argv, const char *prefix __used) 541 { 542 int status; 543 int i,j; 544 545 argc = parse_options(argc, argv, options, stat_usage, 546 PARSE_OPT_STOP_AT_NON_OPTION); 547 if (!argc && target_pid == -1 && target_tid == -1) 548 usage_with_options(stat_usage, options); 549 if (run_count <= 0) 550 usage_with_options(stat_usage, options); 551 552 /* Set attrs and nr_counters if no event is selected and !null_run */ 553 if (!null_run && !nr_counters) { 554 memcpy(attrs, default_attrs, sizeof(default_attrs)); 555 nr_counters = ARRAY_SIZE(default_attrs); 556 } 557 558 if (system_wide) 559 nr_cpus = read_cpu_map(); 560 else 561 nr_cpus = 1; 562 563 if (target_pid != -1) { 564 target_tid = target_pid; 565 thread_num = find_all_tid(target_pid, &all_tids); 566 if (thread_num <= 0) { 567 fprintf(stderr, "Can't find all threads of pid %d\n", 568 target_pid); 569 usage_with_options(stat_usage, options); 570 } 571 } else { 572 all_tids=malloc(sizeof(pid_t)); 573 if (!all_tids) 574 return -ENOMEM; 575 576 all_tids[0] = target_tid; 577 thread_num = 1; 578 } 579 580 for (i = 0; i < MAX_NR_CPUS; i++) { 581 for (j = 0; j < MAX_COUNTERS; j++) { 582 fd[i][j] = malloc(sizeof(int)*thread_num); 583 if (!fd[i][j]) 584 return -ENOMEM; 585 } 586 } 587 588 /* 589 * We dont want to block the signals - that would cause 590 * child tasks to inherit that and Ctrl-C would not work. 591 * What we want is for Ctrl-C to work in the exec()-ed 592 * task, but being ignored by perf stat itself: 593 */ 594 atexit(sig_atexit); 595 signal(SIGINT, skip_signal); 596 signal(SIGALRM, skip_signal); 597 signal(SIGABRT, skip_signal); 598 599 status = 0; 600 for (run_idx = 0; run_idx < run_count; run_idx++) { 601 if (run_count != 1 && verbose) 602 fprintf(stderr, "[ perf stat: executing run #%d ... ]\n", run_idx + 1); 603 status = run_perf_stat(argc, argv); 604 } 605 606 if (status != -1) 607 print_stat(argc, argv); 608 609 return status; 610 } 611