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