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)
  17 #ifndef ARCH_CPU_CLOCK_CYCLES_PER_USEC
  18 static unsigned long cycles_per_usec;
  19 static unsigned long inv_cycles_per_usec;
  20 static uint64_t max_cycles_for_mult;
  21 #endif
  22 #ifdef ARCH_CPU_CLOCK_WRAPS
  23 static unsigned long long cycles_start, cycles_wrap;
  24 #endif
  25 #endif
  26 int tsc_reliable = 0;
  27
  28 struct tv_valid {
  29         uint64_t last_cycles;
  30         int last_tv_valid;
  31         int warned;
  32 };
  33 #ifdef ARCH_HAVE_CPU_CLOCK
  34 #ifdef CONFIG_TLS_THREAD
  35 static __thread struct tv_valid static_tv_valid;
  36 #else
  37 static pthread_key_t tv_tls_key;
  38 #endif
  39 #endif
  40
  41 enum fio_cs fio_clock_source = FIO_PREFERRED_CLOCK_SOURCE;
  42 int fio_clock_source_set = 0;
  43 static enum fio_cs fio_clock_source_inited = CS_INVAL;
  44
  45 #ifdef FIO_DEBUG_TIME
  46
  47 #define HASH_BITS       8
  48 #define HASH_SIZE       (1 << HASH_BITS)
  49
  50 static struct flist_head hash[HASH_SIZE];
  51 static int gtod_inited;
  52
  53 struct gtod_log {
  54         struct flist_head list;
  55         void *caller;
  56         unsigned long calls;
  57 };
  58
  59 static struct gtod_log *find_hash(void *caller)
  60 {
  61         unsigned long h = hash_ptr(caller, HASH_BITS);
  62         struct flist_head *entry;
  63
  64         flist_for_each(entry, &hash[h]) {
  65                 struct gtod_log *log = flist_entry(entry, struct gtod_log,
  66                                                                         list);
  67
  68                 if (log->caller == caller)
  69                         return log;
  70         }
  71
  72         return NULL;
  73 }
  74
  75 static void inc_caller(void *caller)
  76 {
  77         struct gtod_log *log = find_hash(caller);
  78
  79         if (!log) {
  80                 unsigned long h;
  81
  82                 log = malloc(sizeof(*log));
  83                 INIT_FLIST_HEAD(&log->list);
  84                 log->caller = caller;
  85                 log->calls = 0;
  86
  87                 h = hash_ptr(caller, HASH_BITS);
  88                 flist_add_tail(&log->list, &hash[h]);
  89         }
  90
  91         log->calls++;
  92 }
  93
  94 static void gtod_log_caller(void *caller)
  95 {
  96         if (gtod_inited)
  97                 inc_caller(caller);
  98 }
  99
 100 static void fio_exit fio_dump_gtod(void)
 101 {
 102         unsigned long total_calls = 0;
 103         int i;
 104
 105         for (i = 0; i < HASH_SIZE; i++) {
 106                 struct flist_head *entry;
 107                 struct gtod_log *log;
 108
 109                 flist_for_each(entry, &hash[i]) {
 110                         log = flist_entry(entry, struct gtod_log, list);
 111
 112                         printf("function %p, calls %lu\n", log->caller,
 113                                                                 log->calls);
 114                         total_calls += log->calls;
 115                 }
 116         }
 117
 118         printf("Total %lu gettimeofday\n", total_calls);
 119 }
 120
 121 static void fio_init gtod_init(void)
 122 {
 123         int i;
 124
 125         for (i = 0; i < HASH_SIZE; i++)
 126                 INIT_FLIST_HEAD(&hash[i]);
 127
 128         gtod_inited = 1;
 129 }
 130
 131 #endif /* FIO_DEBUG_TIME */
 132
 133 #ifdef CONFIG_CLOCK_GETTIME
 134 static int fill_clock_gettime(struct timespec *ts)
 135 {
 136 #if defined(CONFIG_CLOCK_MONOTONIC_RAW)
 137         return clock_gettime(CLOCK_MONOTONIC_RAW, ts);
 138 #elif defined(CONFIG_CLOCK_MONOTONIC)
 139         return clock_gettime(CLOCK_MONOTONIC, ts);
 140 #else
 141         return clock_gettime(CLOCK_REALTIME, ts);
 142 #endif
 143 }
 144 #endif
 145
 146 static void __fio_gettime(struct timeval *tp)
 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                 struct tv_valid *tv;
 172
 173 #ifdef CONFIG_TLS_THREAD
 174                 tv = &static_tv_valid;
 175 #else
 176                 tv = pthread_getspecific(tv_tls_key);
 177 #endif
 178
 179                 t = get_cpu_clock();
 180 #ifdef ARCH_CPU_CLOCK_WRAPS
 181                 if (t < cycles_start && !cycles_wrap)
 182                         cycles_wrap = 1;
 183                 else if (cycles_wrap && t >= cycles_start && !tv->warned) {
 184                         log_err("fio: double CPU clock wrap\n");
 185                         tv->warned = 1;
 186                 }
 187
 188                 t -= cycles_start;
 189 #endif
 190                 tv->last_cycles = t;
 191                 tv->last_tv_valid = 1;
 192 #ifdef ARCH_CPU_CLOCK_CYCLES_PER_USEC
 193                 usecs = t / ARCH_CPU_CLOCK_CYCLES_PER_USEC;
 194 #else
 195                 if (t < max_cycles_for_mult)
 196                         usecs = (t * inv_cycles_per_usec) / 16777216UL;
 197                 else
 198                         usecs = t / cycles_per_usec;
 199 #endif
 200                 tp->tv_sec = usecs / 1000000;
 201                 tp->tv_usec = usecs % 1000000;
 202                 break;
 203                 }
 204 #endif
 205         default:
 206                 log_err("fio: invalid clock source %d\n", fio_clock_source);
 207                 break;
 208         }
 209 }
 210
 211 #ifdef FIO_DEBUG_TIME
 212 void fio_gettime(struct timeval *tp, void *caller)
 213 #else
 214 void fio_gettime(struct timeval *tp, void fio_unused *caller)
 215 #endif
 216 {
 217 #ifdef FIO_DEBUG_TIME
 218         if (!caller)
 219                 caller = __builtin_return_address(0);
 220
 221         gtod_log_caller(caller);
 222 #endif
 223         if (fio_unlikely(fio_gettime_offload(tp)))
 224                 return;
 225
 226         __fio_gettime(tp);
 227 }
 228
 229 #if defined(ARCH_HAVE_CPU_CLOCK) && !defined(ARCH_CPU_CLOCK_CYCLES_PER_USEC)
 230 static unsigned long get_cycles_per_usec(void)
 231 {
 232         struct timeval s, e;
 233         uint64_t c_s, c_e;
 234         enum fio_cs old_cs = fio_clock_source;
 235         uint64_t elapsed;
 236
 237 #ifdef CONFIG_CLOCK_GETTIME
 238         fio_clock_source = CS_CGETTIME;
 239 #else
 240         fio_clock_source = CS_GTOD;
 241 #endif
 242         __fio_gettime(&s);
 243
 244         c_s = get_cpu_clock();
 245         do {
 246                 __fio_gettime(&e);
 247
 248                 elapsed = utime_since(&s, &e);
 249                 if (elapsed >= 1280) {
 250                         c_e = get_cpu_clock();
 251                         break;
 252                 }
 253         } while (1);
 254
 255         fio_clock_source = old_cs;
 256         return (c_e - c_s) / elapsed;
 257 }
 258
 259 #define NR_TIME_ITERS   50
 260
 261 static int calibrate_cpu_clock(void)
 262 {
 263         double delta, mean, S;
 264         uint64_t minc, maxc, avg, cycles[NR_TIME_ITERS];
 265         int i, samples;
 266
 267         cycles[0] = get_cycles_per_usec();
 268         S = delta = mean = 0.0;
 269         for (i = 0; i < NR_TIME_ITERS; i++) {
 270                 cycles[i] = get_cycles_per_usec();
 271                 delta = cycles[i] - mean;
 272                 if (delta) {
 273                         mean += delta / (i + 1.0);
 274                         S += delta * (cycles[i] - mean);
 275                 }
 276         }
 277
 278         /*
 279          * The most common platform clock breakage is returning zero
 280          * indefinitely. Check for that and return failure.
 281          */
 282         if (!cycles[0] && !cycles[NR_TIME_ITERS - 1])
 283                 return 1;
 284
 285         S = sqrt(S / (NR_TIME_ITERS - 1.0));
 286
 287         minc = -1ULL;
 288         maxc = samples = avg = 0;
 289         for (i = 0; i < NR_TIME_ITERS; i++) {
 290                 double this = cycles[i];
 291
 292                 minc = min(cycles[i], minc);
 293                 maxc = max(cycles[i], maxc);
 294
 295                 if ((fmax(this, mean) - fmin(this, mean)) > S)
 296                         continue;
 297                 samples++;
 298                 avg += this;
 299         }
 300
 301         S /= (double) NR_TIME_ITERS;
 302
 303         for (i = 0; i < NR_TIME_ITERS; i++)
 304                 dprint(FD_TIME, "cycles[%d]=%llu\n", i, (unsigned long long) cycles[i]);
 305
 306         avg /= samples;
 307         dprint(FD_TIME, "avg: %llu\n", (unsigned long long) avg);
 308         dprint(FD_TIME, "min=%llu, max=%llu, mean=%f, S=%f\n",
 309                         (unsigned long long) minc,
 310                         (unsigned long long) maxc, mean, S);
 311
 312         cycles_per_usec = avg;
 313         inv_cycles_per_usec = 16777216UL / cycles_per_usec;
 314         max_cycles_for_mult = ~0ULL / inv_cycles_per_usec;
 315         dprint(FD_TIME, "inv_cycles_per_usec=%lu\n", inv_cycles_per_usec);
 316 #ifdef ARCH_CPU_CLOCK_WRAPS
 317         cycles_start = get_cpu_clock();
 318         dprint(FD_TIME, "cycles_start=%llu\n", cycles_start);
 319 #endif
 320         return 0;
 321 }
 322 #else
 323 static int calibrate_cpu_clock(void)
 324 {
 325 #ifdef ARCH_CPU_CLOCK_CYCLES_PER_USEC
 326         return 0;
 327 #else
 328         return 1;
 329 #endif
 330 }
 331 #endif // ARCH_HAVE_CPU_CLOCK
 332
 333 #ifndef CONFIG_TLS_THREAD
 334 void fio_local_clock_init(int is_thread)
 335 {
 336         struct tv_valid *t;
 337
 338         t = calloc(1, sizeof(*t));
 339         if (pthread_setspecific(tv_tls_key, t)) {
 340                 log_err("fio: can't set TLS key\n");
 341                 assert(0);
 342         }
 343 }
 344
 345 static void kill_tv_tls_key(void *data)
 346 {
 347         free(data);
 348 }
 349 #else
 350 void fio_local_clock_init(int is_thread)
 351 {
 352 }
 353 #endif
 354
 355 void fio_clock_init(void)
 356 {
 357         if (fio_clock_source == fio_clock_source_inited)
 358                 return;
 359
 360 #ifndef CONFIG_TLS_THREAD
 361         if (pthread_key_create(&tv_tls_key, kill_tv_tls_key))
 362                 log_err("fio: can't create TLS key\n");
 363 #endif
 364
 365         fio_clock_source_inited = fio_clock_source;
 366
 367         if (calibrate_cpu_clock())
 368                 tsc_reliable = 0;
 369
 370         /*
 371          * If the arch sets tsc_reliable != 0, then it must be good enough
 372          * to use as THE clock source. For x86 CPUs, this means the TSC
 373          * runs at a constant rate and is synced across CPU cores.
 374          */
 375         if (tsc_reliable) {
 376                 if (!fio_clock_source_set && !fio_monotonic_clocktest(0))
 377                         fio_clock_source = CS_CPUCLOCK;
 378         } else if (fio_clock_source == CS_CPUCLOCK)
 379                 log_info("fio: clocksource=cpu may not be reliable\n");
 380 }
 381
 382 uint64_t utime_since(const struct timeval *s, const struct timeval *e)
 383 {
 384         long sec, usec;
 385         uint64_t ret;
 386
 387         sec = e->tv_sec - s->tv_sec;
 388         usec = e->tv_usec - s->tv_usec;
 389         if (sec > 0 && usec < 0) {
 390                 sec--;
 391                 usec += 1000000;
 392         }
 393
 394         /*
 395          * time warp bug on some kernels?
 396          */
 397         if (sec < 0 || (sec == 0 && usec < 0))
 398                 return 0;
 399
 400         ret = sec * 1000000ULL + usec;
 401
 402         return ret;
 403 }
 404
 405 uint64_t utime_since_now(const struct timeval *s)
 406 {
 407         struct timeval t;
 408
 409         fio_gettime(&t, NULL);
 410         return utime_since(s, &t);
 411 }
 412
 413 uint64_t mtime_since(const struct timeval *s, const struct timeval *e)
 414 {
 415         long sec, usec, ret;
 416
 417         sec = e->tv_sec - s->tv_sec;
 418         usec = e->tv_usec - s->tv_usec;
 419         if (sec > 0 && usec < 0) {
 420                 sec--;
 421                 usec += 1000000;
 422         }
 423
 424         if (sec < 0 || (sec == 0 && usec < 0))
 425                 return 0;
 426
 427         sec *= 1000UL;
 428         usec /= 1000UL;
 429         ret = sec + usec;
 430
 431         return ret;
 432 }
 433
 434 uint64_t mtime_since_now(const struct timeval *s)
 435 {
 436         struct timeval t;
 437         void *p = __builtin_return_address(0);
 438
 439         fio_gettime(&t, p);
 440         return mtime_since(s, &t);
 441 }
 442
 443 uint64_t time_since_now(const struct timeval *s)
 444 {
 445         return mtime_since_now(s) / 1000;
 446 }
 447
 448 #if defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK)  && \
 449     defined(CONFIG_SFAA)
 450
 451 #define CLOCK_ENTRIES_DEBUG     100000
 452 #define CLOCK_ENTRIES_TEST      10000
 453
 454 struct clock_entry {
 455         uint32_t seq;
 456         uint32_t cpu;
 457         uint64_t tsc;
 458 };
 459
 460 struct clock_thread {
 461         pthread_t thread;
 462         int cpu;
 463         int debug;
 464         pthread_mutex_t lock;
 465         pthread_mutex_t started;
 466         unsigned long nr_entries;
 467         uint32_t *seq;
 468         struct clock_entry *entries;
 469 };
 470
 471 static inline uint32_t atomic32_inc_return(uint32_t *seq)
 472 {
 473         return 1 + __sync_fetch_and_add(seq, 1);
 474 }
 475
 476 static void *clock_thread_fn(void *data)
 477 {
 478         struct clock_thread *t = data;
 479         struct clock_entry *c;
 480         os_cpu_mask_t cpu_mask;
 481         uint32_t last_seq;
 482         unsigned long long first;
 483         int i;
 484
 485         if (fio_cpuset_init(&cpu_mask)) {
 486                 int __err = errno;
 487
 488                 log_err("clock cpuset init failed: %s\n", strerror(__err));
 489                 goto err_out;
 490         }
 491
 492         fio_cpu_set(&cpu_mask, t->cpu);
 493
 494         if (fio_setaffinity(gettid(), cpu_mask) == -1) {
 495                 int __err = errno;
 496
 497                 log_err("clock setaffinity failed: %s\n", strerror(__err));
 498                 goto err;
 499         }
 500
 501         pthread_mutex_lock(&t->lock);
 502         pthread_mutex_unlock(&t->started);
 503
 504         first = get_cpu_clock();
 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, first %llu\n", t->cpu,
 528                                                         clocks, first);
 529         }
 530
 531         /*
 532          * The most common platform clock breakage is returning zero
 533          * indefinitely. Check for that and return failure.
 534          */
 535         if (!t->entries[i - 1].tsc && !t->entries[0].tsc)
 536                 goto err;
 537
 538         fio_cpuset_exit(&cpu_mask);
 539         return NULL;
 540 err:
 541         fio_cpuset_exit(&cpu_mask);
 542 err_out:
 543         return (void *) 1;
 544 }
 545
 546 static int clock_cmp(const void *p1, const void *p2)
 547 {
 548         const struct clock_entry *c1 = p1;
 549         const struct clock_entry *c2 = p2;
 550
 551         if (c1->seq == c2->seq)
 552                 log_err("cs: bug in atomic sequence!\n");
 553
 554         return c1->seq - c2->seq;
 555 }
 556
 557 int fio_monotonic_clocktest(int debug)
 558 {
 559         struct clock_thread *cthreads;
 560         unsigned int nr_cpus = cpus_online();
 561         struct clock_entry *entries;
 562         unsigned long nr_entries, tentries, failed = 0;
 563         struct clock_entry *prev, *this;
 564         uint32_t seq = 0;
 565         unsigned int i;
 566
 567         if (debug) {
 568                 log_info("cs: reliable_tsc: %s\n", tsc_reliable ? "yes" : "no");
 569
 570 #ifdef FIO_INC_DEBUG
 571                 fio_debug |= 1U << FD_TIME;
 572 #endif
 573                 nr_entries = CLOCK_ENTRIES_DEBUG;
 574         } else
 575                 nr_entries = CLOCK_ENTRIES_TEST;
 576
 577         calibrate_cpu_clock();
 578
 579         if (debug) {
 580 #ifdef FIO_INC_DEBUG
 581                 fio_debug &= ~(1U << FD_TIME);
 582 #endif
 583         }
 584
 585         cthreads = malloc(nr_cpus * sizeof(struct clock_thread));
 586         tentries = nr_entries * nr_cpus;
 587         entries = malloc(tentries * sizeof(struct clock_entry));
 588
 589         if (debug)
 590                 log_info("cs: Testing %u CPUs\n", nr_cpus);
 591
 592         for (i = 0; i < nr_cpus; i++) {
 593                 struct clock_thread *t = &cthreads[i];
 594
 595                 t->cpu = i;
 596                 t->debug = debug;
 597                 t->seq = &seq;
 598                 t->nr_entries = nr_entries;
 599                 t->entries = &entries[i * nr_entries];
 600                 pthread_mutex_init(&t->lock, NULL);
 601                 pthread_mutex_init(&t->started, NULL);
 602                 pthread_mutex_lock(&t->lock);
 603                 if (pthread_create(&t->thread, NULL, clock_thread_fn, t)) {
 604                         failed++;
 605                         nr_cpus = i;
 606                         break;
 607                 }
 608         }
 609
 610         for (i = 0; i < nr_cpus; i++) {
 611                 struct clock_thread *t = &cthreads[i];
 612
 613                 pthread_mutex_lock(&t->started);
 614         }
 615
 616         for (i = 0; i < nr_cpus; i++) {
 617                 struct clock_thread *t = &cthreads[i];
 618
 619                 pthread_mutex_unlock(&t->lock);
 620         }
 621
 622         for (i = 0; i < nr_cpus; i++) {
 623                 struct clock_thread *t = &cthreads[i];
 624                 void *ret;
 625
 626                 pthread_join(t->thread, &ret);
 627                 if (ret)
 628                         failed++;
 629         }
 630         free(cthreads);
 631
 632         if (failed) {
 633                 if (debug)
 634                         log_err("Clocksource test: %lu threads failed\n", failed);
 635                 goto err;
 636         }
 637
 638         qsort(entries, tentries, sizeof(struct clock_entry), clock_cmp);
 639
 640         /* silence silly gcc */
 641         prev = NULL;
 642         for (failed = i = 0; i < tentries; i++) {
 643                 this = &entries[i];
 644
 645                 if (!i) {
 646                         prev = this;
 647                         continue;
 648                 }
 649
 650                 if (prev->tsc > this->tsc) {
 651                         uint64_t diff = prev->tsc - this->tsc;
 652
 653                         if (!debug) {
 654                                 failed++;
 655                                 break;
 656                         }
 657
 658                         log_info("cs: CPU clock mismatch (diff=%llu):\n",
 659                                                 (unsigned long long) diff);
 660                         log_info("\t CPU%3u: TSC=%llu, SEQ=%u\n", prev->cpu, (unsigned long long) prev->tsc, prev->seq);
 661                         log_info("\t CPU%3u: TSC=%llu, SEQ=%u\n", this->cpu, (unsigned long long) this->tsc, this->seq);
 662                         failed++;
 663                 }
 664
 665                 prev = this;
 666         }
 667
 668         if (debug) {
 669                 if (failed)
 670                         log_info("cs: Failed: %lu\n", failed);
 671                 else
 672                         log_info("cs: Pass!\n");
 673         }
 674 err:
 675         free(entries);
 676         return !!failed;
 677 }
 678
 679 #else /* defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK) */
 680
 681 int fio_monotonic_clocktest(int debug)
 682 {
 683         if (debug)
 684                 log_info("cs: current platform does not support CPU clocks\n");
 685         return 1;
 686 }
 687
 688 #endif