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)
17static unsigned long cycles_per_usec;
18static unsigned long inv_cycles_per_usec;
19#endif
20int tsc_reliable = 0;
21
22struct tv_valid {
23	struct timeval last_tv;
24	uint64_t last_cycles;
25	int last_tv_valid;
26};
27#ifdef CONFIG_TLS_THREAD
28static __thread struct tv_valid static_tv_valid;
29#else
30static pthread_key_t tv_tls_key;
31#endif
32
33enum fio_cs fio_clock_source = FIO_PREFERRED_CLOCK_SOURCE;
34int fio_clock_source_set = 0;
35static 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
42static struct flist_head hash[HASH_SIZE];
43static int gtod_inited;
44
45struct gtod_log {
46	struct flist_head list;
47	void *caller;
48	unsigned long calls;
49};
50
51static 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
67static 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
86static 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
95static 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
116static 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
129static 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
139static 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 (tv && t < tv->last_cycles) {
175			dprint(FD_TIME, "CPU clock going back in time\n");
176			t = tv->last_cycles;
177		} else if (tv)
178			tv->last_cycles = t;
179
180#ifdef ARCH_CPU_CLOCK_CYCLES_PER_USEC
181		usecs = t / ARCH_CPU_CLOCK_CYCLES_PER_USEC;
182#else
183		usecs = (t * inv_cycles_per_usec) / 16777216UL;
184#endif
185		tp->tv_sec = usecs / 1000000;
186		tp->tv_usec = usecs % 1000000;
187		break;
188		}
189#endif
190	default:
191		log_err("fio: invalid clock source %d\n", fio_clock_source);
192		break;
193	}
194
195	return tv;
196}
197
198#ifdef FIO_DEBUG_TIME
199void fio_gettime(struct timeval *tp, void *caller)
200#else
201void fio_gettime(struct timeval *tp, void fio_unused *caller)
202#endif
203{
204	struct tv_valid *tv;
205
206#ifdef FIO_DEBUG_TIME
207	if (!caller)
208		caller = __builtin_return_address(0);
209
210	gtod_log_caller(caller);
211#endif
212	if (fio_unlikely(fio_tv)) {
213		memcpy(tp, fio_tv, sizeof(*tp));
214		return;
215	}
216
217	tv = __fio_gettime(tp);
218
219	/*
220	 * If Linux is using the tsc clock on non-synced processors,
221	 * sometimes time can appear to drift backwards. Fix that up.
222	 */
223	if (tv) {
224		if (tv->last_tv_valid) {
225			if (tp->tv_sec < tv->last_tv.tv_sec)
226				tp->tv_sec = tv->last_tv.tv_sec;
227			else if (tv->last_tv.tv_sec == tp->tv_sec &&
228				 tp->tv_usec < tv->last_tv.tv_usec)
229				tp->tv_usec = tv->last_tv.tv_usec;
230		}
231		tv->last_tv_valid = 1;
232		memcpy(&tv->last_tv, tp, sizeof(*tp));
233	}
234}
235
236#if defined(ARCH_HAVE_CPU_CLOCK) && !defined(ARCH_CPU_CLOCK_CYCLES_PER_USEC)
237static unsigned long get_cycles_per_usec(void)
238{
239	struct timeval s, e;
240	uint64_t c_s, c_e;
241	enum fio_cs old_cs = fio_clock_source;
242
243#ifdef CONFIG_CLOCK_GETTIME
244	fio_clock_source = CS_CGETTIME;
245#else
246	fio_clock_source = CS_GTOD;
247#endif
248	__fio_gettime(&s);
249
250	c_s = get_cpu_clock();
251	do {
252		uint64_t elapsed;
253
254		__fio_gettime(&e);
255
256		elapsed = utime_since(&s, &e);
257		if (elapsed >= 1280) {
258			c_e = get_cpu_clock();
259			break;
260		}
261	} while (1);
262
263	fio_clock_source = old_cs;
264	return (c_e - c_s + 127) >> 7;
265}
266
267#define NR_TIME_ITERS	50
268
269static int calibrate_cpu_clock(void)
270{
271	double delta, mean, S;
272	uint64_t avg, cycles[NR_TIME_ITERS];
273	int i, samples;
274
275	cycles[0] = get_cycles_per_usec();
276	S = delta = mean = 0.0;
277	for (i = 0; i < NR_TIME_ITERS; i++) {
278		cycles[i] = get_cycles_per_usec();
279		delta = cycles[i] - mean;
280		if (delta) {
281			mean += delta / (i + 1.0);
282			S += delta * (cycles[i] - mean);
283		}
284	}
285
286	/*
287	 * The most common platform clock breakage is returning zero
288	 * indefinitely. Check for that and return failure.
289	 */
290	if (!cycles[0] && !cycles[NR_TIME_ITERS - 1])
291		return 1;
292
293	S = sqrt(S / (NR_TIME_ITERS - 1.0));
294
295	samples = avg = 0;
296	for (i = 0; i < NR_TIME_ITERS; i++) {
297		double this = cycles[i];
298
299		if ((fmax(this, mean) - fmin(this, mean)) > S)
300			continue;
301		samples++;
302		avg += this;
303	}
304
305	S /= (double) NR_TIME_ITERS;
306	mean /= 10.0;
307
308	for (i = 0; i < NR_TIME_ITERS; i++)
309		dprint(FD_TIME, "cycles[%d]=%llu\n", i,
310					(unsigned long long) cycles[i] / 10);
311
312	avg /= samples;
313	avg = (avg + 5) / 10;
314	dprint(FD_TIME, "avg: %llu\n", (unsigned long long) avg);
315	dprint(FD_TIME, "mean=%f, S=%f\n", mean, S);
316
317	cycles_per_usec = avg;
318	inv_cycles_per_usec = 16777216UL / cycles_per_usec;
319	dprint(FD_TIME, "inv_cycles_per_usec=%lu\n", inv_cycles_per_usec);
320	return 0;
321}
322#else
323static 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
334void 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}
342
343static void kill_tv_tls_key(void *data)
344{
345	free(data);
346}
347#else
348void fio_local_clock_init(int is_thread)
349{
350}
351#endif
352
353void fio_clock_init(void)
354{
355	if (fio_clock_source == fio_clock_source_inited)
356		return;
357
358#ifndef CONFIG_TLS_THREAD
359	if (pthread_key_create(&tv_tls_key, kill_tv_tls_key))
360		log_err("fio: can't create TLS key\n");
361#endif
362
363	fio_clock_source_inited = fio_clock_source;
364
365	if (calibrate_cpu_clock())
366		tsc_reliable = 0;
367
368	/*
369	 * If the arch sets tsc_reliable != 0, then it must be good enough
370	 * to use as THE clock source. For x86 CPUs, this means the TSC
371	 * runs at a constant rate and is synced across CPU cores.
372	 */
373	if (tsc_reliable) {
374		if (!fio_clock_source_set)
375			fio_clock_source = CS_CPUCLOCK;
376	} else if (fio_clock_source == CS_CPUCLOCK)
377		log_info("fio: clocksource=cpu may not be reliable\n");
378}
379
380uint64_t utime_since(struct timeval *s, struct timeval *e)
381{
382	long sec, usec;
383	uint64_t ret;
384
385	sec = e->tv_sec - s->tv_sec;
386	usec = e->tv_usec - s->tv_usec;
387	if (sec > 0 && usec < 0) {
388		sec--;
389		usec += 1000000;
390	}
391
392	/*
393	 * time warp bug on some kernels?
394	 */
395	if (sec < 0 || (sec == 0 && usec < 0))
396		return 0;
397
398	ret = sec * 1000000ULL + usec;
399
400	return ret;
401}
402
403uint64_t utime_since_now(struct timeval *s)
404{
405	struct timeval t;
406
407	fio_gettime(&t, NULL);
408	return utime_since(s, &t);
409}
410
411uint64_t mtime_since(struct timeval *s, struct timeval *e)
412{
413	long sec, usec, ret;
414
415	sec = e->tv_sec - s->tv_sec;
416	usec = e->tv_usec - s->tv_usec;
417	if (sec > 0 && usec < 0) {
418		sec--;
419		usec += 1000000;
420	}
421
422	if (sec < 0 || (sec == 0 && usec < 0))
423		return 0;
424
425	sec *= 1000UL;
426	usec /= 1000UL;
427	ret = sec + usec;
428
429	return ret;
430}
431
432uint64_t mtime_since_now(struct timeval *s)
433{
434	struct timeval t;
435	void *p = __builtin_return_address(0);
436
437	fio_gettime(&t, p);
438	return mtime_since(s, &t);
439}
440
441uint64_t time_since_now(struct timeval *s)
442{
443	return mtime_since_now(s) / 1000;
444}
445
446#if defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK)  && \
447    defined(CONFIG_SFAA)
448
449#define CLOCK_ENTRIES	100000
450
451struct clock_entry {
452	uint32_t seq;
453	uint32_t cpu;
454	uint64_t tsc;
455};
456
457struct clock_thread {
458	pthread_t thread;
459	int cpu;
460	pthread_mutex_t lock;
461	pthread_mutex_t started;
462	uint32_t *seq;
463	struct clock_entry *entries;
464};
465
466static inline uint32_t atomic32_inc_return(uint32_t *seq)
467{
468	return 1 + __sync_fetch_and_add(seq, 1);
469}
470
471static void *clock_thread_fn(void *data)
472{
473	struct clock_thread *t = data;
474	struct clock_entry *c;
475	os_cpu_mask_t cpu_mask;
476	uint32_t last_seq;
477	int i;
478
479	memset(&cpu_mask, 0, sizeof(cpu_mask));
480	fio_cpu_set(&cpu_mask, t->cpu);
481
482	if (fio_setaffinity(gettid(), cpu_mask) == -1) {
483		log_err("clock setaffinity failed\n");
484		return (void *) 1;
485	}
486
487	pthread_mutex_lock(&t->lock);
488	pthread_mutex_unlock(&t->started);
489
490	last_seq = 0;
491	c = &t->entries[0];
492	for (i = 0; i < CLOCK_ENTRIES; i++, c++) {
493		uint32_t seq;
494		uint64_t tsc;
495
496		c->cpu = t->cpu;
497		do {
498			seq = atomic32_inc_return(t->seq);
499			if (seq < last_seq)
500				break;
501			tsc = get_cpu_clock();
502		} while (seq != *t->seq);
503
504		c->seq = seq;
505		c->tsc = tsc;
506	}
507
508	log_info("cs: cpu%3d: %llu clocks seen\n", t->cpu,
509		(unsigned long long) t->entries[i - 1].tsc - t->entries[0].tsc);
510
511	/*
512	 * The most common platform clock breakage is returning zero
513	 * indefinitely. Check for that and return failure.
514	 */
515	if (!t->entries[i - 1].tsc && !t->entries[0].tsc)
516		return (void *) 1;
517
518	return NULL;
519}
520
521static int clock_cmp(const void *p1, const void *p2)
522{
523	const struct clock_entry *c1 = p1;
524	const struct clock_entry *c2 = p2;
525
526	if (c1->seq == c2->seq)
527		log_err("cs: bug in atomic sequence!\n");
528
529	return c1->seq - c2->seq;
530}
531
532int fio_monotonic_clocktest(void)
533{
534	struct clock_thread *threads;
535	unsigned int nr_cpus = cpus_online();
536	struct clock_entry *entries;
537	unsigned long tentries, failed = 0;
538	struct clock_entry *prev, *this;
539	uint32_t seq = 0;
540	unsigned int i;
541
542	log_info("cs: reliable_tsc: %s\n", tsc_reliable ? "yes" : "no");
543
544	fio_debug |= 1U << FD_TIME;
545	calibrate_cpu_clock();
546	fio_debug &= ~(1U << FD_TIME);
547
548	threads = malloc(nr_cpus * sizeof(struct clock_thread));
549	tentries = CLOCK_ENTRIES * nr_cpus;
550	entries = malloc(tentries * sizeof(struct clock_entry));
551
552	log_info("cs: Testing %u CPUs\n", nr_cpus);
553
554	for (i = 0; i < nr_cpus; i++) {
555		struct clock_thread *t = &threads[i];
556
557		t->cpu = i;
558		t->seq = &seq;
559		t->entries = &entries[i * CLOCK_ENTRIES];
560		pthread_mutex_init(&t->lock, NULL);
561		pthread_mutex_init(&t->started, NULL);
562		pthread_mutex_lock(&t->lock);
563		if (pthread_create(&t->thread, NULL, clock_thread_fn, t)) {
564			failed++;
565			nr_cpus = i;
566			break;
567		}
568	}
569
570	for (i = 0; i < nr_cpus; i++) {
571		struct clock_thread *t = &threads[i];
572
573		pthread_mutex_lock(&t->started);
574	}
575
576	for (i = 0; i < nr_cpus; i++) {
577		struct clock_thread *t = &threads[i];
578
579		pthread_mutex_unlock(&t->lock);
580	}
581
582	for (i = 0; i < nr_cpus; i++) {
583		struct clock_thread *t = &threads[i];
584		void *ret;
585
586		pthread_join(t->thread, &ret);
587		if (ret)
588			failed++;
589	}
590	free(threads);
591
592	if (failed) {
593		log_err("Clocksource test: %lu threads failed\n", failed);
594		goto err;
595	}
596
597	qsort(entries, tentries, sizeof(struct clock_entry), clock_cmp);
598
599	for (failed = i = 0; i < tentries; i++) {
600		this = &entries[i];
601
602		if (!i) {
603			prev = this;
604			continue;
605		}
606
607		if (prev->tsc > this->tsc) {
608			uint64_t diff = prev->tsc - this->tsc;
609
610			log_info("cs: CPU clock mismatch (diff=%llu):\n",
611						(unsigned long long) diff);
612			log_info("\t CPU%3u: TSC=%llu, SEQ=%u\n", prev->cpu, (unsigned long long) prev->tsc, prev->seq);
613			log_info("\t CPU%3u: TSC=%llu, SEQ=%u\n", this->cpu, (unsigned long long) this->tsc, this->seq);
614			failed++;
615		}
616
617		prev = this;
618	}
619
620	if (failed)
621		log_info("cs: Failed: %lu\n", failed);
622	else
623		log_info("cs: Pass!\n");
624
625err:
626	free(entries);
627	return !!failed;
628}
629
630#else /* defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK) */
631
632int fio_monotonic_clocktest(void)
633{
634	log_info("cs: current platform does not support CPU clocks\n");
635	return 0;
636}
637
638#endif
639