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