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
find_hash(void * caller)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
inc_caller(void * caller)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
gtod_log_caller(void * caller)94 static void gtod_log_caller(void *caller)
95 {
96 if (gtod_inited)
97 inc_caller(caller);
98 }
99
fio_dump_gtod(void)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
gtod_init(void)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
fill_clock_gettime(struct timespec * ts)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
__fio_gettime(struct timeval * tp)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
fio_gettime(struct timeval * tp,void * caller)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)
get_cycles_per_usec(void)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
calibrate_cpu_clock(void)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
calibrate_cpu_clock(void)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
fio_local_clock_init(int is_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
kill_tv_tls_key(void * data)345 static void kill_tv_tls_key(void *data)
346 {
347 free(data);
348 }
349 #else
fio_local_clock_init(int is_thread)350 void fio_local_clock_init(int is_thread)
351 {
352 }
353 #endif
354
fio_clock_init(void)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
utime_since(const struct timeval * s,const struct timeval * e)382 uint64_t utime_since(const struct timeval *s, const struct timeval *e)
383 {
384 int64_t sec, usec;
385
386 sec = e->tv_sec - s->tv_sec;
387 usec = e->tv_usec - s->tv_usec;
388 if (sec > 0 && usec < 0) {
389 sec--;
390 usec += 1000000;
391 }
392
393 /*
394 * time warp bug on some kernels?
395 */
396 if (sec < 0 || (sec == 0 && usec < 0))
397 return 0;
398
399 return usec + (sec * 1000000);
400 }
401
utime_since_now(const struct timeval * s)402 uint64_t utime_since_now(const struct timeval *s)
403 {
404 struct timeval t;
405 #ifdef FIO_DEBUG_TIME
406 void *p = __builtin_return_address(0);
407
408 fio_gettime(&t, p);
409 #else
410 fio_gettime(&t, NULL);
411 #endif
412
413 return utime_since(s, &t);
414 }
415
mtime_since(const struct timeval * s,const struct timeval * e)416 uint64_t mtime_since(const struct timeval *s, const struct timeval *e)
417 {
418 long sec, usec;
419
420 sec = e->tv_sec - s->tv_sec;
421 usec = e->tv_usec - s->tv_usec;
422 if (sec > 0 && usec < 0) {
423 sec--;
424 usec += 1000000;
425 }
426
427 if (sec < 0 || (sec == 0 && usec < 0))
428 return 0;
429
430 sec *= 1000;
431 usec /= 1000;
432 return sec + usec;
433 }
434
mtime_since_now(const struct timeval * s)435 uint64_t mtime_since_now(const struct timeval *s)
436 {
437 struct timeval t;
438 #ifdef FIO_DEBUG_TIME
439 void *p = __builtin_return_address(0);
440
441 fio_gettime(&t, p);
442 #else
443 fio_gettime(&t, NULL);
444 #endif
445
446 return mtime_since(s, &t);
447 }
448
time_since_now(const struct timeval * s)449 uint64_t time_since_now(const struct timeval *s)
450 {
451 return mtime_since_now(s) / 1000;
452 }
453
454 #if defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK) && \
455 defined(CONFIG_SFAA)
456
457 #define CLOCK_ENTRIES_DEBUG 100000
458 #define CLOCK_ENTRIES_TEST 10000
459
460 struct clock_entry {
461 uint32_t seq;
462 uint32_t cpu;
463 uint64_t tsc;
464 };
465
466 struct clock_thread {
467 pthread_t thread;
468 int cpu;
469 int debug;
470 pthread_mutex_t lock;
471 pthread_mutex_t started;
472 unsigned long nr_entries;
473 uint32_t *seq;
474 struct clock_entry *entries;
475 };
476
atomic32_inc_return(uint32_t * seq)477 static inline uint32_t atomic32_inc_return(uint32_t *seq)
478 {
479 return 1 + __sync_fetch_and_add(seq, 1);
480 }
481
clock_thread_fn(void * data)482 static void *clock_thread_fn(void *data)
483 {
484 struct clock_thread *t = data;
485 struct clock_entry *c;
486 os_cpu_mask_t cpu_mask;
487 uint32_t last_seq;
488 unsigned long long first;
489 int i;
490
491 if (fio_cpuset_init(&cpu_mask)) {
492 int __err = errno;
493
494 log_err("clock cpuset init failed: %s\n", strerror(__err));
495 goto err_out;
496 }
497
498 fio_cpu_set(&cpu_mask, t->cpu);
499
500 if (fio_setaffinity(gettid(), cpu_mask) == -1) {
501 int __err = errno;
502
503 log_err("clock setaffinity failed: %s\n", strerror(__err));
504 goto err;
505 }
506
507 pthread_mutex_lock(&t->lock);
508 pthread_mutex_unlock(&t->started);
509
510 first = get_cpu_clock();
511 last_seq = 0;
512 c = &t->entries[0];
513 for (i = 0; i < t->nr_entries; i++, c++) {
514 uint32_t seq;
515 uint64_t tsc;
516
517 c->cpu = t->cpu;
518 do {
519 seq = atomic32_inc_return(t->seq);
520 if (seq < last_seq)
521 break;
522 tsc = get_cpu_clock();
523 } while (seq != *t->seq);
524
525 c->seq = seq;
526 c->tsc = tsc;
527 }
528
529 if (t->debug) {
530 unsigned long long clocks;
531
532 clocks = t->entries[i - 1].tsc - t->entries[0].tsc;
533 log_info("cs: cpu%3d: %llu clocks seen, first %llu\n", t->cpu,
534 clocks, first);
535 }
536
537 /*
538 * The most common platform clock breakage is returning zero
539 * indefinitely. Check for that and return failure.
540 */
541 if (!t->entries[i - 1].tsc && !t->entries[0].tsc)
542 goto err;
543
544 fio_cpuset_exit(&cpu_mask);
545 return NULL;
546 err:
547 fio_cpuset_exit(&cpu_mask);
548 err_out:
549 return (void *) 1;
550 }
551
clock_cmp(const void * p1,const void * p2)552 static int clock_cmp(const void *p1, const void *p2)
553 {
554 const struct clock_entry *c1 = p1;
555 const struct clock_entry *c2 = p2;
556
557 if (c1->seq == c2->seq)
558 log_err("cs: bug in atomic sequence!\n");
559
560 return c1->seq - c2->seq;
561 }
562
fio_monotonic_clocktest(int debug)563 int fio_monotonic_clocktest(int debug)
564 {
565 struct clock_thread *cthreads;
566 unsigned int nr_cpus = cpus_online();
567 struct clock_entry *entries;
568 unsigned long nr_entries, tentries, failed = 0;
569 struct clock_entry *prev, *this;
570 uint32_t seq = 0;
571 unsigned int i;
572
573 if (debug) {
574 log_info("cs: reliable_tsc: %s\n", tsc_reliable ? "yes" : "no");
575
576 #ifdef FIO_INC_DEBUG
577 fio_debug |= 1U << FD_TIME;
578 #endif
579 nr_entries = CLOCK_ENTRIES_DEBUG;
580 } else
581 nr_entries = CLOCK_ENTRIES_TEST;
582
583 calibrate_cpu_clock();
584
585 if (debug) {
586 #ifdef FIO_INC_DEBUG
587 fio_debug &= ~(1U << FD_TIME);
588 #endif
589 }
590
591 cthreads = malloc(nr_cpus * sizeof(struct clock_thread));
592 tentries = nr_entries * nr_cpus;
593 entries = malloc(tentries * sizeof(struct clock_entry));
594
595 if (debug)
596 log_info("cs: Testing %u CPUs\n", nr_cpus);
597
598 for (i = 0; i < nr_cpus; i++) {
599 struct clock_thread *t = &cthreads[i];
600
601 t->cpu = i;
602 t->debug = debug;
603 t->seq = &seq;
604 t->nr_entries = nr_entries;
605 t->entries = &entries[i * nr_entries];
606 pthread_mutex_init(&t->lock, NULL);
607 pthread_mutex_init(&t->started, NULL);
608 pthread_mutex_lock(&t->lock);
609 if (pthread_create(&t->thread, NULL, clock_thread_fn, t)) {
610 failed++;
611 nr_cpus = i;
612 break;
613 }
614 }
615
616 for (i = 0; i < nr_cpus; i++) {
617 struct clock_thread *t = &cthreads[i];
618
619 pthread_mutex_lock(&t->started);
620 }
621
622 for (i = 0; i < nr_cpus; i++) {
623 struct clock_thread *t = &cthreads[i];
624
625 pthread_mutex_unlock(&t->lock);
626 }
627
628 for (i = 0; i < nr_cpus; i++) {
629 struct clock_thread *t = &cthreads[i];
630 void *ret;
631
632 pthread_join(t->thread, &ret);
633 if (ret)
634 failed++;
635 }
636 free(cthreads);
637
638 if (failed) {
639 if (debug)
640 log_err("Clocksource test: %lu threads failed\n", failed);
641 goto err;
642 }
643
644 qsort(entries, tentries, sizeof(struct clock_entry), clock_cmp);
645
646 /* silence silly gcc */
647 prev = NULL;
648 for (failed = i = 0; i < tentries; i++) {
649 this = &entries[i];
650
651 if (!i) {
652 prev = this;
653 continue;
654 }
655
656 if (prev->tsc > this->tsc) {
657 uint64_t diff = prev->tsc - this->tsc;
658
659 if (!debug) {
660 failed++;
661 break;
662 }
663
664 log_info("cs: CPU clock mismatch (diff=%llu):\n",
665 (unsigned long long) diff);
666 log_info("\t CPU%3u: TSC=%llu, SEQ=%u\n", prev->cpu, (unsigned long long) prev->tsc, prev->seq);
667 log_info("\t CPU%3u: TSC=%llu, SEQ=%u\n", this->cpu, (unsigned long long) this->tsc, this->seq);
668 failed++;
669 }
670
671 prev = this;
672 }
673
674 if (debug) {
675 if (failed)
676 log_info("cs: Failed: %lu\n", failed);
677 else
678 log_info("cs: Pass!\n");
679 }
680 err:
681 free(entries);
682 return !!failed;
683 }
684
685 #else /* defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK) */
686
fio_monotonic_clocktest(int debug)687 int fio_monotonic_clocktest(int debug)
688 {
689 if (debug)
690 log_info("cs: current platform does not support CPU clocks\n");
691 return 1;
692 }
693
694 #endif
695