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) 17 #ifndef ARCH_CPU_CLOCK_CYCLES_PER_USEC 18 static unsigned long cycles_per_usec; 19 static unsigned long inv_cycles_per_usec; 20 static uint64_t max_cycles_for_mult; 21 #endif 22 #ifdef ARCH_CPU_CLOCK_WRAPS 23 static unsigned long long cycles_start, cycles_wrap; 24 #endif 25 #endif 26 int tsc_reliable = 0; 27 28 struct tv_valid { 29 uint64_t last_cycles; 30 int last_tv_valid; 31 int warned; 32 }; 33 #ifdef ARCH_HAVE_CPU_CLOCK 34 #ifdef CONFIG_TLS_THREAD 35 static __thread struct tv_valid static_tv_valid; 36 #else 37 static pthread_key_t tv_tls_key; 38 #endif 39 #endif 40 41 enum fio_cs fio_clock_source = FIO_PREFERRED_CLOCK_SOURCE; 42 int fio_clock_source_set = 0; 43 static enum fio_cs fio_clock_source_inited = CS_INVAL; 44 45 #ifdef FIO_DEBUG_TIME 46 47 #define HASH_BITS 8 48 #define HASH_SIZE (1 << HASH_BITS) 49 50 static struct flist_head hash[HASH_SIZE]; 51 static int gtod_inited; 52 53 struct gtod_log { 54 struct flist_head list; 55 void *caller; 56 unsigned long calls; 57 }; 58 59 static struct gtod_log *find_hash(void *caller) 60 { 61 unsigned long h = hash_ptr(caller, HASH_BITS); 62 struct flist_head *entry; 63 64 flist_for_each(entry, &hash[h]) { 65 struct gtod_log *log = flist_entry(entry, struct gtod_log, 66 list); 67 68 if (log->caller == caller) 69 return log; 70 } 71 72 return NULL; 73 } 74 75 static void inc_caller(void *caller) 76 { 77 struct gtod_log *log = find_hash(caller); 78 79 if (!log) { 80 unsigned long h; 81 82 log = malloc(sizeof(*log)); 83 INIT_FLIST_HEAD(&log->list); 84 log->caller = caller; 85 log->calls = 0; 86 87 h = hash_ptr(caller, HASH_BITS); 88 flist_add_tail(&log->list, &hash[h]); 89 } 90 91 log->calls++; 92 } 93 94 static void gtod_log_caller(void *caller) 95 { 96 if (gtod_inited) 97 inc_caller(caller); 98 } 99 100 static void fio_exit fio_dump_gtod(void) 101 { 102 unsigned long total_calls = 0; 103 int i; 104 105 for (i = 0; i < HASH_SIZE; i++) { 106 struct flist_head *entry; 107 struct gtod_log *log; 108 109 flist_for_each(entry, &hash[i]) { 110 log = flist_entry(entry, struct gtod_log, list); 111 112 printf("function %p, calls %lu\n", log->caller, 113 log->calls); 114 total_calls += log->calls; 115 } 116 } 117 118 printf("Total %lu gettimeofday\n", total_calls); 119 } 120 121 static void fio_init gtod_init(void) 122 { 123 int i; 124 125 for (i = 0; i < HASH_SIZE; i++) 126 INIT_FLIST_HEAD(&hash[i]); 127 128 gtod_inited = 1; 129 } 130 131 #endif /* FIO_DEBUG_TIME */ 132 133 #ifdef CONFIG_CLOCK_GETTIME 134 static int fill_clock_gettime(struct timespec *ts) 135 { 136 #if defined(CONFIG_CLOCK_MONOTONIC_RAW) 137 return clock_gettime(CLOCK_MONOTONIC_RAW, ts); 138 #elif defined(CONFIG_CLOCK_MONOTONIC) 139 return clock_gettime(CLOCK_MONOTONIC, ts); 140 #else 141 return clock_gettime(CLOCK_REALTIME, ts); 142 #endif 143 } 144 #endif 145 146 static void __fio_gettime(struct timeval *tp) 147 { 148 switch (fio_clock_source) { 149 #ifdef CONFIG_GETTIMEOFDAY 150 case CS_GTOD: 151 gettimeofday(tp, NULL); 152 break; 153 #endif 154 #ifdef CONFIG_CLOCK_GETTIME 155 case CS_CGETTIME: { 156 struct timespec ts; 157 158 if (fill_clock_gettime(&ts) < 0) { 159 log_err("fio: clock_gettime fails\n"); 160 assert(0); 161 } 162 163 tp->tv_sec = ts.tv_sec; 164 tp->tv_usec = ts.tv_nsec / 1000; 165 break; 166 } 167 #endif 168 #ifdef ARCH_HAVE_CPU_CLOCK 169 case CS_CPUCLOCK: { 170 uint64_t usecs, t; 171 struct tv_valid *tv; 172 173 #ifdef CONFIG_TLS_THREAD 174 tv = &static_tv_valid; 175 #else 176 tv = pthread_getspecific(tv_tls_key); 177 #endif 178 179 t = get_cpu_clock(); 180 #ifdef ARCH_CPU_CLOCK_WRAPS 181 if (t < cycles_start && !cycles_wrap) 182 cycles_wrap = 1; 183 else if (cycles_wrap && t >= cycles_start && !tv->warned) { 184 log_err("fio: double CPU clock wrap\n"); 185 tv->warned = 1; 186 } 187 188 t -= cycles_start; 189 #endif 190 tv->last_cycles = t; 191 tv->last_tv_valid = 1; 192 #ifdef ARCH_CPU_CLOCK_CYCLES_PER_USEC 193 usecs = t / ARCH_CPU_CLOCK_CYCLES_PER_USEC; 194 #else 195 if (t < max_cycles_for_mult) 196 usecs = (t * inv_cycles_per_usec) / 16777216UL; 197 else 198 usecs = t / cycles_per_usec; 199 #endif 200 tp->tv_sec = usecs / 1000000; 201 tp->tv_usec = usecs % 1000000; 202 break; 203 } 204 #endif 205 default: 206 log_err("fio: invalid clock source %d\n", fio_clock_source); 207 break; 208 } 209 } 210 211 #ifdef FIO_DEBUG_TIME 212 void fio_gettime(struct timeval *tp, void *caller) 213 #else 214 void fio_gettime(struct timeval *tp, void fio_unused *caller) 215 #endif 216 { 217 #ifdef FIO_DEBUG_TIME 218 if (!caller) 219 caller = __builtin_return_address(0); 220 221 gtod_log_caller(caller); 222 #endif 223 if (fio_unlikely(fio_gettime_offload(tp))) 224 return; 225 226 __fio_gettime(tp); 227 } 228 229 #if defined(ARCH_HAVE_CPU_CLOCK) && !defined(ARCH_CPU_CLOCK_CYCLES_PER_USEC) 230 static unsigned long get_cycles_per_usec(void) 231 { 232 struct timeval s, e; 233 uint64_t c_s, c_e; 234 enum fio_cs old_cs = fio_clock_source; 235 uint64_t elapsed; 236 237 #ifdef CONFIG_CLOCK_GETTIME 238 fio_clock_source = CS_CGETTIME; 239 #else 240 fio_clock_source = CS_GTOD; 241 #endif 242 __fio_gettime(&s); 243 244 c_s = get_cpu_clock(); 245 do { 246 __fio_gettime(&e); 247 248 elapsed = utime_since(&s, &e); 249 if (elapsed >= 1280) { 250 c_e = get_cpu_clock(); 251 break; 252 } 253 } while (1); 254 255 fio_clock_source = old_cs; 256 return (c_e - c_s) / elapsed; 257 } 258 259 #define NR_TIME_ITERS 50 260 261 static int calibrate_cpu_clock(void) 262 { 263 double delta, mean, S; 264 uint64_t minc, maxc, avg, cycles[NR_TIME_ITERS]; 265 int i, samples; 266 267 cycles[0] = get_cycles_per_usec(); 268 S = delta = mean = 0.0; 269 for (i = 0; i < NR_TIME_ITERS; i++) { 270 cycles[i] = get_cycles_per_usec(); 271 delta = cycles[i] - mean; 272 if (delta) { 273 mean += delta / (i + 1.0); 274 S += delta * (cycles[i] - mean); 275 } 276 } 277 278 /* 279 * The most common platform clock breakage is returning zero 280 * indefinitely. Check for that and return failure. 281 */ 282 if (!cycles[0] && !cycles[NR_TIME_ITERS - 1]) 283 return 1; 284 285 S = sqrt(S / (NR_TIME_ITERS - 1.0)); 286 287 minc = -1ULL; 288 maxc = samples = avg = 0; 289 for (i = 0; i < NR_TIME_ITERS; i++) { 290 double this = cycles[i]; 291 292 minc = min(cycles[i], minc); 293 maxc = max(cycles[i], maxc); 294 295 if ((fmax(this, mean) - fmin(this, mean)) > S) 296 continue; 297 samples++; 298 avg += this; 299 } 300 301 S /= (double) NR_TIME_ITERS; 302 303 for (i = 0; i < NR_TIME_ITERS; i++) 304 dprint(FD_TIME, "cycles[%d]=%llu\n", i, (unsigned long long) cycles[i]); 305 306 avg /= samples; 307 dprint(FD_TIME, "avg: %llu\n", (unsigned long long) avg); 308 dprint(FD_TIME, "min=%llu, max=%llu, mean=%f, S=%f\n", 309 (unsigned long long) minc, 310 (unsigned long long) maxc, mean, S); 311 312 cycles_per_usec = avg; 313 inv_cycles_per_usec = 16777216UL / cycles_per_usec; 314 max_cycles_for_mult = ~0ULL / inv_cycles_per_usec; 315 dprint(FD_TIME, "inv_cycles_per_usec=%lu\n", inv_cycles_per_usec); 316 #ifdef ARCH_CPU_CLOCK_WRAPS 317 cycles_start = get_cpu_clock(); 318 dprint(FD_TIME, "cycles_start=%llu\n", cycles_start); 319 #endif 320 return 0; 321 } 322 #else 323 static int calibrate_cpu_clock(void) 324 { 325 #ifdef ARCH_CPU_CLOCK_CYCLES_PER_USEC 326 return 0; 327 #else 328 return 1; 329 #endif 330 } 331 #endif // ARCH_HAVE_CPU_CLOCK 332 333 #ifndef CONFIG_TLS_THREAD 334 void fio_local_clock_init(int is_thread) 335 { 336 struct tv_valid *t; 337 338 t = calloc(1, sizeof(*t)); 339 if (pthread_setspecific(tv_tls_key, t)) { 340 log_err("fio: can't set TLS key\n"); 341 assert(0); 342 } 343 } 344 345 static void kill_tv_tls_key(void *data) 346 { 347 free(data); 348 } 349 #else 350 void fio_local_clock_init(int is_thread) 351 { 352 } 353 #endif 354 355 void fio_clock_init(void) 356 { 357 if (fio_clock_source == fio_clock_source_inited) 358 return; 359 360 #ifndef CONFIG_TLS_THREAD 361 if (pthread_key_create(&tv_tls_key, kill_tv_tls_key)) 362 log_err("fio: can't create TLS key\n"); 363 #endif 364 365 fio_clock_source_inited = fio_clock_source; 366 367 if (calibrate_cpu_clock()) 368 tsc_reliable = 0; 369 370 /* 371 * If the arch sets tsc_reliable != 0, then it must be good enough 372 * to use as THE clock source. For x86 CPUs, this means the TSC 373 * runs at a constant rate and is synced across CPU cores. 374 */ 375 if (tsc_reliable) { 376 if (!fio_clock_source_set && !fio_monotonic_clocktest(0)) 377 fio_clock_source = CS_CPUCLOCK; 378 } else if (fio_clock_source == CS_CPUCLOCK) 379 log_info("fio: clocksource=cpu may not be reliable\n"); 380 } 381 382 uint64_t utime_since(const struct timeval *s, const struct timeval *e) 383 { 384 int64_t sec, usec; 385 386 sec = e->tv_sec - s->tv_sec; 387 usec = e->tv_usec - s->tv_usec; 388 if (sec > 0 && usec < 0) { 389 sec--; 390 usec += 1000000; 391 } 392 393 /* 394 * time warp bug on some kernels? 395 */ 396 if (sec < 0 || (sec == 0 && usec < 0)) 397 return 0; 398 399 return usec + (sec * 1000000); 400 } 401 402 uint64_t utime_since_now(const struct timeval *s) 403 { 404 struct timeval t; 405 #ifdef FIO_DEBUG_TIME 406 void *p = __builtin_return_address(0); 407 408 fio_gettime(&t, p); 409 #else 410 fio_gettime(&t, NULL); 411 #endif 412 413 return utime_since(s, &t); 414 } 415 416 uint64_t mtime_since(const struct timeval *s, const struct timeval *e) 417 { 418 long sec, usec; 419 420 sec = e->tv_sec - s->tv_sec; 421 usec = e->tv_usec - s->tv_usec; 422 if (sec > 0 && usec < 0) { 423 sec--; 424 usec += 1000000; 425 } 426 427 if (sec < 0 || (sec == 0 && usec < 0)) 428 return 0; 429 430 sec *= 1000; 431 usec /= 1000; 432 return sec + usec; 433 } 434 435 uint64_t mtime_since_now(const struct timeval *s) 436 { 437 struct timeval t; 438 #ifdef FIO_DEBUG_TIME 439 void *p = __builtin_return_address(0); 440 441 fio_gettime(&t, p); 442 #else 443 fio_gettime(&t, NULL); 444 #endif 445 446 return mtime_since(s, &t); 447 } 448 449 uint64_t time_since_now(const struct timeval *s) 450 { 451 return mtime_since_now(s) / 1000; 452 } 453 454 #if defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK) && \ 455 defined(CONFIG_SFAA) 456 457 #define CLOCK_ENTRIES_DEBUG 100000 458 #define CLOCK_ENTRIES_TEST 10000 459 460 struct clock_entry { 461 uint32_t seq; 462 uint32_t cpu; 463 uint64_t tsc; 464 }; 465 466 struct clock_thread { 467 pthread_t thread; 468 int cpu; 469 int debug; 470 pthread_mutex_t lock; 471 pthread_mutex_t started; 472 unsigned long nr_entries; 473 uint32_t *seq; 474 struct clock_entry *entries; 475 }; 476 477 static inline uint32_t atomic32_inc_return(uint32_t *seq) 478 { 479 return 1 + __sync_fetch_and_add(seq, 1); 480 } 481 482 static void *clock_thread_fn(void *data) 483 { 484 struct clock_thread *t = data; 485 struct clock_entry *c; 486 os_cpu_mask_t cpu_mask; 487 uint32_t last_seq; 488 unsigned long long first; 489 int i; 490 491 if (fio_cpuset_init(&cpu_mask)) { 492 int __err = errno; 493 494 log_err("clock cpuset init failed: %s\n", strerror(__err)); 495 goto err_out; 496 } 497 498 fio_cpu_set(&cpu_mask, t->cpu); 499 500 if (fio_setaffinity(gettid(), cpu_mask) == -1) { 501 int __err = errno; 502 503 log_err("clock setaffinity failed: %s\n", strerror(__err)); 504 goto err; 505 } 506 507 pthread_mutex_lock(&t->lock); 508 pthread_mutex_unlock(&t->started); 509 510 first = get_cpu_clock(); 511 last_seq = 0; 512 c = &t->entries[0]; 513 for (i = 0; i < t->nr_entries; i++, c++) { 514 uint32_t seq; 515 uint64_t tsc; 516 517 c->cpu = t->cpu; 518 do { 519 seq = atomic32_inc_return(t->seq); 520 if (seq < last_seq) 521 break; 522 tsc = get_cpu_clock(); 523 } while (seq != *t->seq); 524 525 c->seq = seq; 526 c->tsc = tsc; 527 } 528 529 if (t->debug) { 530 unsigned long long clocks; 531 532 clocks = t->entries[i - 1].tsc - t->entries[0].tsc; 533 log_info("cs: cpu%3d: %llu clocks seen, first %llu\n", t->cpu, 534 clocks, first); 535 } 536 537 /* 538 * The most common platform clock breakage is returning zero 539 * indefinitely. Check for that and return failure. 540 */ 541 if (!t->entries[i - 1].tsc && !t->entries[0].tsc) 542 goto err; 543 544 fio_cpuset_exit(&cpu_mask); 545 return NULL; 546 err: 547 fio_cpuset_exit(&cpu_mask); 548 err_out: 549 return (void *) 1; 550 } 551 552 static int clock_cmp(const void *p1, const void *p2) 553 { 554 const struct clock_entry *c1 = p1; 555 const struct clock_entry *c2 = p2; 556 557 if (c1->seq == c2->seq) 558 log_err("cs: bug in atomic sequence!\n"); 559 560 return c1->seq - c2->seq; 561 } 562 563 int fio_monotonic_clocktest(int debug) 564 { 565 struct clock_thread *cthreads; 566 unsigned int nr_cpus = cpus_online(); 567 struct clock_entry *entries; 568 unsigned long nr_entries, tentries, failed = 0; 569 struct clock_entry *prev, *this; 570 uint32_t seq = 0; 571 unsigned int i; 572 573 if (debug) { 574 log_info("cs: reliable_tsc: %s\n", tsc_reliable ? "yes" : "no"); 575 576 #ifdef FIO_INC_DEBUG 577 fio_debug |= 1U << FD_TIME; 578 #endif 579 nr_entries = CLOCK_ENTRIES_DEBUG; 580 } else 581 nr_entries = CLOCK_ENTRIES_TEST; 582 583 calibrate_cpu_clock(); 584 585 if (debug) { 586 #ifdef FIO_INC_DEBUG 587 fio_debug &= ~(1U << FD_TIME); 588 #endif 589 } 590 591 cthreads = malloc(nr_cpus * sizeof(struct clock_thread)); 592 tentries = nr_entries * nr_cpus; 593 entries = malloc(tentries * sizeof(struct clock_entry)); 594 595 if (debug) 596 log_info("cs: Testing %u CPUs\n", nr_cpus); 597 598 for (i = 0; i < nr_cpus; i++) { 599 struct clock_thread *t = &cthreads[i]; 600 601 t->cpu = i; 602 t->debug = debug; 603 t->seq = &seq; 604 t->nr_entries = nr_entries; 605 t->entries = &entries[i * nr_entries]; 606 pthread_mutex_init(&t->lock, NULL); 607 pthread_mutex_init(&t->started, NULL); 608 pthread_mutex_lock(&t->lock); 609 if (pthread_create(&t->thread, NULL, clock_thread_fn, t)) { 610 failed++; 611 nr_cpus = i; 612 break; 613 } 614 } 615 616 for (i = 0; i < nr_cpus; i++) { 617 struct clock_thread *t = &cthreads[i]; 618 619 pthread_mutex_lock(&t->started); 620 } 621 622 for (i = 0; i < nr_cpus; i++) { 623 struct clock_thread *t = &cthreads[i]; 624 625 pthread_mutex_unlock(&t->lock); 626 } 627 628 for (i = 0; i < nr_cpus; i++) { 629 struct clock_thread *t = &cthreads[i]; 630 void *ret; 631 632 pthread_join(t->thread, &ret); 633 if (ret) 634 failed++; 635 } 636 free(cthreads); 637 638 if (failed) { 639 if (debug) 640 log_err("Clocksource test: %lu threads failed\n", failed); 641 goto err; 642 } 643 644 qsort(entries, tentries, sizeof(struct clock_entry), clock_cmp); 645 646 /* silence silly gcc */ 647 prev = NULL; 648 for (failed = i = 0; i < tentries; i++) { 649 this = &entries[i]; 650 651 if (!i) { 652 prev = this; 653 continue; 654 } 655 656 if (prev->tsc > this->tsc) { 657 uint64_t diff = prev->tsc - this->tsc; 658 659 if (!debug) { 660 failed++; 661 break; 662 } 663 664 log_info("cs: CPU clock mismatch (diff=%llu):\n", 665 (unsigned long long) diff); 666 log_info("\t CPU%3u: TSC=%llu, SEQ=%u\n", prev->cpu, (unsigned long long) prev->tsc, prev->seq); 667 log_info("\t CPU%3u: TSC=%llu, SEQ=%u\n", this->cpu, (unsigned long long) this->tsc, this->seq); 668 failed++; 669 } 670 671 prev = this; 672 } 673 674 if (debug) { 675 if (failed) 676 log_info("cs: Failed: %lu\n", failed); 677 else 678 log_info("cs: Pass!\n"); 679 } 680 err: 681 free(entries); 682 return !!failed; 683 } 684 685 #else /* defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK) */ 686 687 int fio_monotonic_clocktest(int debug) 688 { 689 if (debug) 690 log_info("cs: current platform does not support CPU clocks\n"); 691 return 1; 692 } 693 694 #endif 695
