gettime.c

   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