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