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