1 /* 2 * Clock functions 3 */ 4 5 #include <unistd.h> 6 #include <math.h> 7 #include <sys/time.h> 8 #include <time.h> 9 10 #include "fio.h" 11 #include "smalloc.h" 12 13 #include "hash.h" 14 #include "os/os.h" 15 16 #if defined(ARCH_HAVE_CPU_CLOCK) && !defined(ARCH_CPU_CLOCK_CYCLES_PER_USEC) 17 static unsigned long cycles_per_usec; 18 static unsigned long inv_cycles_per_usec; 19 static uint64_t max_cycles_for_mult; 20 #endif 21 #ifdef ARCH_CPU_CLOCK_WRAPS 22 static unsigned long long cycles_start, cycles_wrap; 23 #endif 24 int tsc_reliable = 0; 25 26 struct tv_valid { 27 uint64_t last_cycles; 28 int last_tv_valid; 29 int warned; 30 }; 31 #ifdef ARCH_HAVE_CPU_CLOCK 32 #ifdef CONFIG_TLS_THREAD 33 static __thread struct tv_valid static_tv_valid; 34 #else 35 static pthread_key_t tv_tls_key; 36 #endif 37 #endif 38 39 enum fio_cs fio_clock_source = FIO_PREFERRED_CLOCK_SOURCE; 40 int fio_clock_source_set = 0; 41 static enum fio_cs fio_clock_source_inited = CS_INVAL; 42 43 #ifdef FIO_DEBUG_TIME 44 45 #define HASH_BITS 8 46 #define HASH_SIZE (1 << HASH_BITS) 47 48 static struct flist_head hash[HASH_SIZE]; 49 static int gtod_inited; 50 51 struct gtod_log { 52 struct flist_head list; 53 void *caller; 54 unsigned long calls; 55 }; 56 57 static struct gtod_log *find_hash(void *caller) 58 { 59 unsigned long h = hash_ptr(caller, HASH_BITS); 60 struct flist_head *entry; 61 62 flist_for_each(entry, &hash[h]) { 63 struct gtod_log *log = flist_entry(entry, struct gtod_log, 64 list); 65 66 if (log->caller == caller) 67 return log; 68 } 69 70 return NULL; 71 } 72 73 static void inc_caller(void *caller) 74 { 75 struct gtod_log *log = find_hash(caller); 76 77 if (!log) { 78 unsigned long h; 79 80 log = malloc(sizeof(*log)); 81 INIT_FLIST_HEAD(&log->list); 82 log->caller = caller; 83 log->calls = 0; 84 85 h = hash_ptr(caller, HASH_BITS); 86 flist_add_tail(&log->list, &hash[h]); 87 } 88 89 log->calls++; 90 } 91 92 static void gtod_log_caller(void *caller) 93 { 94 if (gtod_inited) 95 inc_caller(caller); 96 } 97 98 static void fio_exit fio_dump_gtod(void) 99 { 100 unsigned long total_calls = 0; 101 int i; 102 103 for (i = 0; i < HASH_SIZE; i++) { 104 struct flist_head *entry; 105 struct gtod_log *log; 106 107 flist_for_each(entry, &hash[i]) { 108 log = flist_entry(entry, struct gtod_log, list); 109 110 printf("function %p, calls %lu\n", log->caller, 111 log->calls); 112 total_calls += log->calls; 113 } 114 } 115 116 printf("Total %lu gettimeofday\n", total_calls); 117 } 118 119 static void fio_init gtod_init(void) 120 { 121 int i; 122 123 for (i = 0; i < HASH_SIZE; i++) 124 INIT_FLIST_HEAD(&hash[i]); 125 126 gtod_inited = 1; 127 } 128 129 #endif /* FIO_DEBUG_TIME */ 130 131 #ifdef CONFIG_CLOCK_GETTIME 132 static int fill_clock_gettime(struct timespec *ts) 133 { 134 #ifdef CONFIG_CLOCK_MONOTONIC 135 return clock_gettime(CLOCK_MONOTONIC, ts); 136 #else 137 return clock_gettime(CLOCK_REALTIME, ts); 138 #endif 139 } 140 #endif 141 142 static void __fio_gettime(struct timeval *tp) 143 { 144 switch (fio_clock_source) { 145 #ifdef CONFIG_GETTIMEOFDAY 146 case CS_GTOD: 147 gettimeofday(tp, NULL); 148 break; 149 #endif 150 #ifdef CONFIG_CLOCK_GETTIME 151 case CS_CGETTIME: { 152 struct timespec ts; 153 154 if (fill_clock_gettime(&ts) < 0) { 155 log_err("fio: clock_gettime fails\n"); 156 assert(0); 157 } 158 159 tp->tv_sec = ts.tv_sec; 160 tp->tv_usec = ts.tv_nsec / 1000; 161 break; 162 } 163 #endif 164 #ifdef ARCH_HAVE_CPU_CLOCK 165 case CS_CPUCLOCK: { 166 uint64_t usecs, t; 167 struct tv_valid *tv; 168 169 #ifdef CONFIG_TLS_THREAD 170 tv = &static_tv_valid; 171 #else 172 tv = pthread_getspecific(tv_tls_key); 173 #endif 174 175 t = get_cpu_clock(); 176 #ifdef ARCH_CPU_CLOCK_WRAPS 177 if (t < cycles_start && !cycles_wrap) 178 cycles_wrap = 1; 179 else if (cycles_wrap && t >= cycles_start && !tv->warned) { 180 log_err("fio: double CPU clock wrap\n"); 181 tv->warned = 1; 182 } 183 184 t -= cycles_start; 185 #endif 186 tv->last_cycles = t; 187 tv->last_tv_valid = 1; 188 #ifdef ARCH_CPU_CLOCK_CYCLES_PER_USEC 189 usecs = t / ARCH_CPU_CLOCK_CYCLES_PER_USEC; 190 #else 191 if (t < max_cycles_for_mult) 192 usecs = (t * inv_cycles_per_usec) / 16777216UL; 193 else 194 usecs = t / cycles_per_usec; 195 #endif 196 tp->tv_sec = usecs / 1000000; 197 tp->tv_usec = usecs % 1000000; 198 break; 199 } 200 #endif 201 default: 202 log_err("fio: invalid clock source %d\n", fio_clock_source); 203 break; 204 } 205 } 206 207 #ifdef FIO_DEBUG_TIME 208 void fio_gettime(struct timeval *tp, void *caller) 209 #else 210 void fio_gettime(struct timeval *tp, void fio_unused *caller) 211 #endif 212 { 213 #ifdef FIO_DEBUG_TIME 214 if (!caller) 215 caller = __builtin_return_address(0); 216 217 gtod_log_caller(caller); 218 #endif 219 if (fio_unlikely(fio_gettime_offload(tp))) 220 return; 221 222 __fio_gettime(tp); 223 } 224 225 #if defined(ARCH_HAVE_CPU_CLOCK) && !defined(ARCH_CPU_CLOCK_CYCLES_PER_USEC) 226 static unsigned long get_cycles_per_usec(void) 227 { 228 struct timeval s, e; 229 uint64_t c_s, c_e; 230 enum fio_cs old_cs = fio_clock_source; 231 232 #ifdef CONFIG_CLOCK_GETTIME 233 fio_clock_source = CS_CGETTIME; 234 #else 235 fio_clock_source = CS_GTOD; 236 #endif 237 __fio_gettime(&s); 238 239 c_s = get_cpu_clock(); 240 do { 241 uint64_t elapsed; 242 243 __fio_gettime(&e); 244 245 elapsed = utime_since(&s, &e); 246 if (elapsed >= 1280) { 247 c_e = get_cpu_clock(); 248 break; 249 } 250 } while (1); 251 252 fio_clock_source = old_cs; 253 return (c_e - c_s + 127) >> 7; 254 } 255 256 #define NR_TIME_ITERS 50 257 258 static int calibrate_cpu_clock(void) 259 { 260 double delta, mean, S; 261 uint64_t minc, maxc, avg, cycles[NR_TIME_ITERS]; 262 int i, samples; 263 264 cycles[0] = get_cycles_per_usec(); 265 S = delta = mean = 0.0; 266 for (i = 0; i < NR_TIME_ITERS; i++) { 267 cycles[i] = get_cycles_per_usec(); 268 delta = cycles[i] - mean; 269 if (delta) { 270 mean += delta / (i + 1.0); 271 S += delta * (cycles[i] - mean); 272 } 273 } 274 275 /* 276 * The most common platform clock breakage is returning zero 277 * indefinitely. Check for that and return failure. 278 */ 279 if (!cycles[0] && !cycles[NR_TIME_ITERS - 1]) 280 return 1; 281 282 S = sqrt(S / (NR_TIME_ITERS - 1.0)); 283 284 minc = -1ULL; 285 maxc = samples = avg = 0; 286 for (i = 0; i < NR_TIME_ITERS; i++) { 287 double this = cycles[i]; 288 289 minc = min(cycles[i], minc); 290 maxc = max(cycles[i], maxc); 291 292 if ((fmax(this, mean) - fmin(this, mean)) > S) 293 continue; 294 samples++; 295 avg += this; 296 } 297 298 S /= (double) NR_TIME_ITERS; 299 mean /= 10.0; 300 301 for (i = 0; i < NR_TIME_ITERS; i++) 302 dprint(FD_TIME, "cycles[%d]=%llu\n", i, 303 (unsigned long long) cycles[i] / 10); 304 305 avg /= samples; 306 avg = (avg + 5) / 10; 307 minc /= 10; 308 maxc /= 10; 309 dprint(FD_TIME, "avg: %llu\n", (unsigned long long) avg); 310 dprint(FD_TIME, "min=%llu, max=%llu, mean=%f, S=%f\n", 311 (unsigned long long) minc, 312 (unsigned long long) maxc, mean, S); 313 314 cycles_per_usec = avg; 315 inv_cycles_per_usec = 16777216UL / cycles_per_usec; 316 max_cycles_for_mult = ~0ULL / inv_cycles_per_usec; 317 dprint(FD_TIME, "inv_cycles_per_usec=%lu\n", inv_cycles_per_usec); 318 #ifdef ARCH_CPU_CLOCK_WRAPS 319 cycles_start = get_cpu_clock(); 320 dprint(FD_TIME, "cycles_start=%llu\n", cycles_start); 321 #endif 322 return 0; 323 } 324 #else 325 static int calibrate_cpu_clock(void) 326 { 327 #ifdef ARCH_CPU_CLOCK_CYCLES_PER_USEC 328 return 0; 329 #else 330 return 1; 331 #endif 332 } 333 #endif // ARCH_HAVE_CPU_CLOCK 334 335 #ifndef CONFIG_TLS_THREAD 336 void fio_local_clock_init(int is_thread) 337 { 338 struct tv_valid *t; 339 340 t = calloc(1, sizeof(*t)); 341 if (pthread_setspecific(tv_tls_key, t)) { 342 log_err("fio: can't set TLS key\n"); 343 assert(0); 344 } 345 } 346 347 static void kill_tv_tls_key(void *data) 348 { 349 free(data); 350 } 351 #else 352 void fio_local_clock_init(int is_thread) 353 { 354 } 355 #endif 356 357 void fio_clock_init(void) 358 { 359 if (fio_clock_source == fio_clock_source_inited) 360 return; 361 362 #ifndef CONFIG_TLS_THREAD 363 if (pthread_key_create(&tv_tls_key, kill_tv_tls_key)) 364 log_err("fio: can't create TLS key\n"); 365 #endif 366 367 fio_clock_source_inited = fio_clock_source; 368 369 if (calibrate_cpu_clock()) 370 tsc_reliable = 0; 371 372 /* 373 * If the arch sets tsc_reliable != 0, then it must be good enough 374 * to use as THE clock source. For x86 CPUs, this means the TSC 375 * runs at a constant rate and is synced across CPU cores. 376 */ 377 if (tsc_reliable) { 378 if (!fio_clock_source_set && !fio_monotonic_clocktest(0)) 379 fio_clock_source = CS_CPUCLOCK; 380 } else if (fio_clock_source == CS_CPUCLOCK) 381 log_info("fio: clocksource=cpu may not be reliable\n"); 382 } 383 384 uint64_t utime_since(const struct timeval *s, const struct timeval *e) 385 { 386 long sec, usec; 387 uint64_t ret; 388 389 sec = e->tv_sec - s->tv_sec; 390 usec = e->tv_usec - s->tv_usec; 391 if (sec > 0 && usec < 0) { 392 sec--; 393 usec += 1000000; 394 } 395 396 /* 397 * time warp bug on some kernels? 398 */ 399 if (sec < 0 || (sec == 0 && usec < 0)) 400 return 0; 401 402 ret = sec * 1000000ULL + usec; 403 404 return ret; 405 } 406 407 uint64_t utime_since_now(const struct timeval *s) 408 { 409 struct timeval t; 410 411 fio_gettime(&t, NULL); 412 return utime_since(s, &t); 413 } 414 415 uint64_t mtime_since(const struct timeval *s, const struct timeval *e) 416 { 417 long sec, usec, ret; 418 419 sec = e->tv_sec - s->tv_sec; 420 usec = e->tv_usec - s->tv_usec; 421 if (sec > 0 && usec < 0) { 422 sec--; 423 usec += 1000000; 424 } 425 426 if (sec < 0 || (sec == 0 && usec < 0)) 427 return 0; 428 429 sec *= 1000UL; 430 usec /= 1000UL; 431 ret = sec + usec; 432 433 return ret; 434 } 435 436 uint64_t mtime_since_now(const struct timeval *s) 437 { 438 struct timeval t; 439 void *p = __builtin_return_address(0); 440 441 fio_gettime(&t, p); 442 return mtime_since(s, &t); 443 } 444 445 uint64_t time_since_now(const struct timeval *s) 446 { 447 return mtime_since_now(s) / 1000; 448 } 449 450 #if defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK) && \ 451 defined(CONFIG_SFAA) 452 453 #define CLOCK_ENTRIES_DEBUG 100000 454 #define CLOCK_ENTRIES_TEST 10000 455 456 struct clock_entry { 457 uint32_t seq; 458 uint32_t cpu; 459 uint64_t tsc; 460 }; 461 462 struct clock_thread { 463 pthread_t thread; 464 int cpu; 465 int debug; 466 pthread_mutex_t lock; 467 pthread_mutex_t started; 468 unsigned long nr_entries; 469 uint32_t *seq; 470 struct clock_entry *entries; 471 }; 472 473 static inline uint32_t atomic32_inc_return(uint32_t *seq) 474 { 475 return 1 + __sync_fetch_and_add(seq, 1); 476 } 477 478 static void *clock_thread_fn(void *data) 479 { 480 struct clock_thread *t = data; 481 struct clock_entry *c; 482 os_cpu_mask_t cpu_mask; 483 uint32_t last_seq; 484 int i; 485 486 if (fio_cpuset_init(&cpu_mask)) { 487 int __err = errno; 488 489 log_err("clock cpuset init failed: %s\n", strerror(__err)); 490 goto err_out; 491 } 492 493 fio_cpu_set(&cpu_mask, t->cpu); 494 495 if (fio_setaffinity(gettid(), cpu_mask) == -1) { 496 int __err = errno; 497 498 log_err("clock setaffinity failed: %s\n", strerror(__err)); 499 goto err; 500 } 501 502 pthread_mutex_lock(&t->lock); 503 pthread_mutex_unlock(&t->started); 504 505 last_seq = 0; 506 c = &t->entries[0]; 507 for (i = 0; i < t->nr_entries; i++, c++) { 508 uint32_t seq; 509 uint64_t tsc; 510 511 c->cpu = t->cpu; 512 do { 513 seq = atomic32_inc_return(t->seq); 514 if (seq < last_seq) 515 break; 516 tsc = get_cpu_clock(); 517 } while (seq != *t->seq); 518 519 c->seq = seq; 520 c->tsc = tsc; 521 } 522 523 if (t->debug) { 524 unsigned long long clocks; 525 526 clocks = t->entries[i - 1].tsc - t->entries[0].tsc; 527 log_info("cs: cpu%3d: %llu clocks seen\n", t->cpu, clocks); 528 } 529 530 /* 531 * The most common platform clock breakage is returning zero 532 * indefinitely. Check for that and return failure. 533 */ 534 if (!t->entries[i - 1].tsc && !t->entries[0].tsc) 535 goto err; 536 537 fio_cpuset_exit(&cpu_mask); 538 return NULL; 539 err: 540 fio_cpuset_exit(&cpu_mask); 541 err_out: 542 return (void *) 1; 543 } 544 545 static int clock_cmp(const void *p1, const void *p2) 546 { 547 const struct clock_entry *c1 = p1; 548 const struct clock_entry *c2 = p2; 549 550 if (c1->seq == c2->seq) 551 log_err("cs: bug in atomic sequence!\n"); 552 553 return c1->seq - c2->seq; 554 } 555 556 int fio_monotonic_clocktest(int debug) 557 { 558 struct clock_thread *cthreads; 559 unsigned int nr_cpus = cpus_online(); 560 struct clock_entry *entries; 561 unsigned long nr_entries, tentries, failed = 0; 562 struct clock_entry *prev, *this; 563 uint32_t seq = 0; 564 unsigned int i; 565 566 if (debug) { 567 log_info("cs: reliable_tsc: %s\n", tsc_reliable ? "yes" : "no"); 568 569 #ifdef FIO_INC_DEBUG 570 fio_debug |= 1U << FD_TIME; 571 #endif 572 nr_entries = CLOCK_ENTRIES_DEBUG; 573 } else 574 nr_entries = CLOCK_ENTRIES_TEST; 575 576 calibrate_cpu_clock(); 577 578 if (debug) { 579 #ifdef FIO_INC_DEBUG 580 fio_debug &= ~(1U << FD_TIME); 581 #endif 582 } 583 584 cthreads = malloc(nr_cpus * sizeof(struct clock_thread)); 585 tentries = nr_entries * nr_cpus; 586 entries = malloc(tentries * sizeof(struct clock_entry)); 587 588 if (debug) 589 log_info("cs: Testing %u CPUs\n", nr_cpus); 590 591 for (i = 0; i < nr_cpus; i++) { 592 struct clock_thread *t = &cthreads[i]; 593 594 t->cpu = i; 595 t->debug = debug; 596 t->seq = &seq; 597 t->nr_entries = nr_entries; 598 t->entries = &entries[i * nr_entries]; 599 pthread_mutex_init(&t->lock, NULL); 600 pthread_mutex_init(&t->started, NULL); 601 pthread_mutex_lock(&t->lock); 602 if (pthread_create(&t->thread, NULL, clock_thread_fn, t)) { 603 failed++; 604 nr_cpus = i; 605 break; 606 } 607 } 608 609 for (i = 0; i < nr_cpus; i++) { 610 struct clock_thread *t = &cthreads[i]; 611 612 pthread_mutex_lock(&t->started); 613 } 614 615 for (i = 0; i < nr_cpus; i++) { 616 struct clock_thread *t = &cthreads[i]; 617 618 pthread_mutex_unlock(&t->lock); 619 } 620 621 for (i = 0; i < nr_cpus; i++) { 622 struct clock_thread *t = &cthreads[i]; 623 void *ret; 624 625 pthread_join(t->thread, &ret); 626 if (ret) 627 failed++; 628 } 629 free(cthreads); 630 631 if (failed) { 632 if (debug) 633 log_err("Clocksource test: %lu threads failed\n", failed); 634 goto err; 635 } 636 637 qsort(entries, tentries, sizeof(struct clock_entry), clock_cmp); 638 639 for (failed = i = 0; i < tentries; i++) { 640 this = &entries[i]; 641 642 if (!i) { 643 prev = this; 644 continue; 645 } 646 647 if (prev->tsc > this->tsc) { 648 uint64_t diff = prev->tsc - this->tsc; 649 650 if (!debug) { 651 failed++; 652 break; 653 } 654 655 log_info("cs: CPU clock mismatch (diff=%llu):\n", 656 (unsigned long long) diff); 657 log_info("\t CPU%3u: TSC=%llu, SEQ=%u\n", prev->cpu, (unsigned long long) prev->tsc, prev->seq); 658 log_info("\t CPU%3u: TSC=%llu, SEQ=%u\n", this->cpu, (unsigned long long) this->tsc, this->seq); 659 failed++; 660 } 661 662 prev = this; 663 } 664 665 if (debug) { 666 if (failed) 667 log_info("cs: Failed: %lu\n", failed); 668 else 669 log_info("cs: Pass!\n"); 670 } 671 err: 672 free(entries); 673 return !!failed; 674 } 675 676 #else /* defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK) */ 677 678 int fio_monotonic_clocktest(int debug) 679 { 680 if (debug) 681 log_info("cs: current platform does not support CPU clocks\n"); 682 return 1; 683 } 684 685 #endif 686
