text: /*
   * Clock functions
   */
  
  #include <unistd.h>
  #include <math.h>
  #include <sys/time.h>
  #include <time.h>
  
  #include "fio.h"
  #include "smalloc.h"
  
  #include "hash.h"
  #include "os/os.h"
  
  #if defined(ARCH_HAVE_CPU_CLOCK) && !defined(ARCH_CPU_CLOCK_CYCLES_PER_USEC)
  static unsigned long cycles_per_usec;
  static unsigned long inv_cycles_per_usec;
  static uint64_t max_cycles_for_mult;
  #endif
  #ifdef ARCH_CPU_CLOCK_WRAPS
  static unsigned long long cycles_start, cycles_wrap;
  #endif
  int tsc_reliable = 0;
  
  struct tv_valid {
  	uint64_t last_cycles;
  	int last_tv_valid;
  	int warned;
  };
  #ifdef ARCH_HAVE_CPU_CLOCK
  #ifdef CONFIG_TLS_THREAD
  static __thread struct tv_valid static_tv_valid;
  #else
  static pthread_key_t tv_tls_key;
  #endif
  #endif
  
  enum fio_cs fio_clock_source = FIO_PREFERRED_CLOCK_SOURCE;
  int fio_clock_source_set = 0;
  static enum fio_cs fio_clock_source_inited = CS_INVAL;
  
  #ifdef FIO_DEBUG_TIME
  
  #define HASH_BITS	8
  #define HASH_SIZE	(1 << HASH_BITS)
  
  static struct flist_head hash[HASH_SIZE];
  static int gtod_inited;
  
  struct gtod_log {
  	struct flist_head list;
  	void *caller;
  	unsigned long calls;
  };
  
  static struct gtod_log *find_hash(void *caller)
  {
  	unsigned long h = hash_ptr(caller, HASH_BITS);
  	struct flist_head *entry;
  
  	flist_for_each(entry, &hash[h]) {
  		struct gtod_log *log = flist_entry(entry, struct gtod_log,
  									list);
  
  		if (log->caller == caller)
  			return log;
  	}
  
  	return NULL;
  }
  
  static void inc_caller(void *caller)
  {
  	struct gtod_log *log = find_hash(caller);
  
  	if (!log) {
  		unsigned long h;
  
  		log = malloc(sizeof(*log));
  		INIT_FLIST_HEAD(&log->list);
  		log->caller = caller;
  		log->calls = 0;
  
  		h = hash_ptr(caller, HASH_BITS);
  		flist_add_tail(&log->list, &hash[h]);
  	}
  
  	log->calls++;
  }
  
  static void gtod_log_caller(void *caller)
  {
  	if (gtod_inited)
  		inc_caller(caller);
  }
  
  static void fio_exit fio_dump_gtod(void)
  {
  	unsigned long total_calls = 0;
  	int i;
  
  	for (i = 0; i < HASH_SIZE; i++) {
  		struct flist_head *entry;
  		struct gtod_log *log;
  
  		flist_for_each(entry, &hash[i]) {
  			log = flist_entry(entry, struct gtod_log, list);
  
  			printf("function %p, calls %lu\n", log->caller,
  								log->calls);
  			total_calls += log->calls;
  		}
  	}
  
  	printf("Total %lu gettimeofday\n", total_calls);
  }
  
  static void fio_init gtod_init(void)
  {
  	int i;
  
  	for (i = 0; i < HASH_SIZE; i++)
  		INIT_FLIST_HEAD(&hash[i]);
  
  	gtod_inited = 1;
  }
  
  #endif /* FIO_DEBUG_TIME */
  
  #ifdef CONFIG_CLOCK_GETTIME
  static int fill_clock_gettime(struct timespec *ts)
  {
  #ifdef CONFIG_CLOCK_MONOTONIC
  	return clock_gettime(CLOCK_MONOTONIC, ts);
  #else
  	return clock_gettime(CLOCK_REALTIME, ts);
  #endif
  }
  #endif
  
  static void __fio_gettime(struct timeval *tp)
  {
  	switch (fio_clock_source) {
  #ifdef CONFIG_GETTIMEOFDAY
  	case CS_GTOD:
  		gettimeofday(tp, NULL);
  		break;
  #endif
  #ifdef CONFIG_CLOCK_GETTIME
  	case CS_CGETTIME: {
  		struct timespec ts;
  
  		if (fill_clock_gettime(&ts) < 0) {
  			log_err("fio: clock_gettime fails\n");
  			assert(0);
  		}
  
  		tp->tv_sec = ts.tv_sec;
  		tp->tv_usec = ts.tv_nsec / 1000;
  		break;
  		}
  #endif
  #ifdef ARCH_HAVE_CPU_CLOCK
  	case CS_CPUCLOCK: {
  		uint64_t usecs, t;
  		struct tv_valid *tv;
  
  #ifdef CONFIG_TLS_THREAD
  		tv = &static_tv_valid;
  #else
  		tv = pthread_getspecific(tv_tls_key);
  #endif
  
  		t = get_cpu_clock();
  #ifdef ARCH_CPU_CLOCK_WRAPS
  		if (t < cycles_start && !cycles_wrap)
  			cycles_wrap = 1;
  		else if (cycles_wrap && t >= cycles_start && !tv->warned) {
  			log_err("fio: double CPU clock wrap\n");
  			tv->warned = 1;
  		}
  
  		t -= cycles_start;
  #endif
  		tv->last_cycles = t;
  		tv->last_tv_valid = 1;
  #ifdef ARCH_CPU_CLOCK_CYCLES_PER_USEC
  		usecs = t / ARCH_CPU_CLOCK_CYCLES_PER_USEC;
  #else
  		if (t < max_cycles_for_mult)
  			usecs = (t * inv_cycles_per_usec) / 16777216UL;
  		else
  			usecs = t / cycles_per_usec;
  #endif
  		tp->tv_sec = usecs / 1000000;
  		tp->tv_usec = usecs % 1000000;
  		break;
  		}
  #endif
  	default:
  		log_err("fio: invalid clock source %d\n", fio_clock_source);
  		break;
  	}
  }
  
  #ifdef FIO_DEBUG_TIME
  void fio_gettime(struct timeval *tp, void *caller)
  #else
  void fio_gettime(struct timeval *tp, void fio_unused *caller)
  #endif
  {
  #ifdef FIO_DEBUG_TIME
  	if (!caller)
  		caller = __builtin_return_address(0);
  
  	gtod_log_caller(caller);
  #endif
  	if (fio_unlikely(fio_gettime_offload(tp)))
  		return;
  
  	__fio_gettime(tp);
  }
  
  #if defined(ARCH_HAVE_CPU_CLOCK) && !defined(ARCH_CPU_CLOCK_CYCLES_PER_USEC)
  static unsigned long get_cycles_per_usec(void)
  {
  	struct timeval s, e;
  	uint64_t c_s, c_e;
  	enum fio_cs old_cs = fio_clock_source;
  
  #ifdef CONFIG_CLOCK_GETTIME
  	fio_clock_source = CS_CGETTIME;
  #else
  	fio_clock_source = CS_GTOD;
  #endif
  	__fio_gettime(&s);
  
  	c_s = get_cpu_clock();
  	do {
  		uint64_t elapsed;
  
  		__fio_gettime(&e);
  
  		elapsed = utime_since(&s, &e);
  		if (elapsed >= 1280) {
  			c_e = get_cpu_clock();
  			break;
  		}
  	} while (1);
  
  	fio_clock_source = old_cs;
  	return (c_e - c_s + 127) >> 7;
  }
  
  #define NR_TIME_ITERS	50
  
  static int calibrate_cpu_clock(void)
  {
  	double delta, mean, S;
  	uint64_t minc, maxc, avg, cycles[NR_TIME_ITERS];
  	int i, samples;
  
  	cycles[0] = get_cycles_per_usec();
  	S = delta = mean = 0.0;
  	for (i = 0; i < NR_TIME_ITERS; i++) {
  		cycles[i] = get_cycles_per_usec();
  		delta = cycles[i] - mean;
  		if (delta) {
  			mean += delta / (i + 1.0);
  			S += delta * (cycles[i] - mean);
  		}
  	}
  
  	/*
  	 * The most common platform clock breakage is returning zero
  	 * indefinitely. Check for that and return failure.
  	 */
  	if (!cycles[0] && !cycles[NR_TIME_ITERS - 1])
  		return 1;
  
  	S = sqrt(S / (NR_TIME_ITERS - 1.0));
  
  	minc = -1ULL;
  	maxc = samples = avg = 0;
  	for (i = 0; i < NR_TIME_ITERS; i++) {
  		double this = cycles[i];
  
  		minc = min(cycles[i], minc);
  		maxc = max(cycles[i], maxc);
  
  		if ((fmax(this, mean) - fmin(this, mean)) > S)
  			continue;
  		samples++;
  		avg += this;
  	}
  
  	S /= (double) NR_TIME_ITERS;
  	mean /= 10.0;
  
  	for (i = 0; i < NR_TIME_ITERS; i++)
  		dprint(FD_TIME, "cycles[%d]=%llu\n", i,
  					(unsigned long long) cycles[i] / 10);
  
  	avg /= samples;
  	avg = (avg + 5) / 10;
  	minc /= 10;
  	maxc /= 10;
  	dprint(FD_TIME, "avg: %llu\n", (unsigned long long) avg);
  	dprint(FD_TIME, "min=%llu, max=%llu, mean=%f, S=%f\n",
  			(unsigned long long) minc,
  			(unsigned long long) maxc, mean, S);
  
  	cycles_per_usec = avg;
  	inv_cycles_per_usec = 16777216UL / cycles_per_usec;
  	max_cycles_for_mult = ~0ULL / inv_cycles_per_usec;
  	dprint(FD_TIME, "inv_cycles_per_usec=%lu\n", inv_cycles_per_usec);
  #ifdef ARCH_CPU_CLOCK_WRAPS
  	cycles_start = get_cpu_clock();
  	dprint(FD_TIME, "cycles_start=%llu\n", cycles_start);
  #endif
  	return 0;
  }
  #else
  static int calibrate_cpu_clock(void)
  {
  #ifdef ARCH_CPU_CLOCK_CYCLES_PER_USEC
  	return 0;
  #else
  	return 1;
  #endif
  }
  #endif // ARCH_HAVE_CPU_CLOCK
  
  #ifndef CONFIG_TLS_THREAD
  void fio_local_clock_init(int is_thread)
  {
  	struct tv_valid *t;
  
  	t = calloc(1, sizeof(*t));
  	if (pthread_setspecific(tv_tls_key, t)) {
  		log_err("fio: can't set TLS key\n");
  		assert(0);
  	}
  }
  
  static void kill_tv_tls_key(void *data)
  {
  	free(data);
  }
  #else
  void fio_local_clock_init(int is_thread)
  {
  }
  #endif
  
  void fio_clock_init(void)
  {
  	if (fio_clock_source == fio_clock_source_inited)
  		return;
  
  #ifndef CONFIG_TLS_THREAD
  	if (pthread_key_create(&tv_tls_key, kill_tv_tls_key))
  		log_err("fio: can't create TLS key\n");
  #endif
  
  	fio_clock_source_inited = fio_clock_source;
  
  	if (calibrate_cpu_clock())
  		tsc_reliable = 0;
  
  	/*
  	 * If the arch sets tsc_reliable != 0, then it must be good enough
  	 * to use as THE clock source. For x86 CPUs, this means the TSC
  	 * runs at a constant rate and is synced across CPU cores.
  	 */
  	if (tsc_reliable) {
  		if (!fio_clock_source_set && !fio_monotonic_clocktest(0))
  			fio_clock_source = CS_CPUCLOCK;
  	} else if (fio_clock_source == CS_CPUCLOCK)
  		log_info("fio: clocksource=cpu may not be reliable\n");
  }
  
  uint64_t utime_since(const struct timeval *s, const struct timeval *e)
  {
  	long sec, usec;
  	uint64_t ret;
  
  	sec = e->tv_sec - s->tv_sec;
  	usec = e->tv_usec - s->tv_usec;
  	if (sec > 0 && usec < 0) {
  		sec--;
  		usec += 1000000;
  	}
  
  	/*
  	 * time warp bug on some kernels?
  	 */
  	if (sec < 0 || (sec == 0 && usec < 0))
  		return 0;
  
  	ret = sec * 1000000ULL + usec;
  
  	return ret;
  }
  
  uint64_t utime_since_now(const struct timeval *s)
  {
  	struct timeval t;
  
  	fio_gettime(&t, NULL);
  	return utime_since(s, &t);
  }
  
  uint64_t mtime_since(const struct timeval *s, const struct timeval *e)
  {
  	long sec, usec, ret;
  
  	sec = e->tv_sec - s->tv_sec;
  	usec = e->tv_usec - s->tv_usec;
  	if (sec > 0 && usec < 0) {
  		sec--;
  		usec += 1000000;
  	}
  
  	if (sec < 0 || (sec == 0 && usec < 0))
  		return 0;
  
  	sec *= 1000UL;
  	usec /= 1000UL;
  	ret = sec + usec;
  
  	return ret;
  }
  
  uint64_t mtime_since_now(const struct timeval *s)
  {
  	struct timeval t;
  	void *p = __builtin_return_address(0);
  
  	fio_gettime(&t, p);
  	return mtime_since(s, &t);
  }
  
  uint64_t time_since_now(const struct timeval *s)
  {
  	return mtime_since_now(s) / 1000;
  }
  
  #if defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK)  && \
      defined(CONFIG_SFAA)
  
  #define CLOCK_ENTRIES_DEBUG	100000
  #define CLOCK_ENTRIES_TEST	10000
  
  struct clock_entry {
  	uint32_t seq;
  	uint32_t cpu;
  	uint64_t tsc;
  };
  
  struct clock_thread {
  	pthread_t thread;
  	int cpu;
  	int debug;
  	pthread_mutex_t lock;
  	pthread_mutex_t started;
  	unsigned long nr_entries;
  	uint32_t *seq;
  	struct clock_entry *entries;
  };
  
  static inline uint32_t atomic32_inc_return(uint32_t *seq)
  {
  	return 1 + __sync_fetch_and_add(seq, 1);
  }
  
  static void *clock_thread_fn(void *data)
  {
  	struct clock_thread *t = data;
  	struct clock_entry *c;
  	os_cpu_mask_t cpu_mask;
  	uint32_t last_seq;
  	int i;
  
  	if (fio_cpuset_init(&cpu_mask)) {
  		int __err = errno;
  
  		log_err("clock cpuset init failed: %s\n", strerror(__err));
  		goto err_out;
  	}
  
  	fio_cpu_set(&cpu_mask, t->cpu);
  
  	if (fio_setaffinity(gettid(), cpu_mask) == -1) {
  		int __err = errno;
  
  		log_err("clock setaffinity failed: %s\n", strerror(__err));
  		goto err;
  	}
  
  	pthread_mutex_lock(&t->lock);
  	pthread_mutex_unlock(&t->started);
  
  	last_seq = 0;
  	c = &t->entries[0];
  	for (i = 0; i < t->nr_entries; i++, c++) {
  		uint32_t seq;
  		uint64_t tsc;
  
  		c->cpu = t->cpu;
  		do {
  			seq = atomic32_inc_return(t->seq);
  			if (seq < last_seq)
  				break;
  			tsc = get_cpu_clock();
  		} while (seq != *t->seq);
  
  		c->seq = seq;
  		c->tsc = tsc;
  	}
  
  	if (t->debug) {
  		unsigned long long clocks;
  
  		clocks = t->entries[i - 1].tsc - t->entries[0].tsc;
  		log_info("cs: cpu%3d: %llu clocks seen\n", t->cpu, clocks);
  	}
  
  	/*
  	 * The most common platform clock breakage is returning zero
  	 * indefinitely. Check for that and return failure.
  	 */
  	if (!t->entries[i - 1].tsc && !t->entries[0].tsc)
  		goto err;
  
  	fio_cpuset_exit(&cpu_mask);
  	return NULL;
  err:
  	fio_cpuset_exit(&cpu_mask);
  err_out:
  	return (void *) 1;
  }
  
  static int clock_cmp(const void *p1, const void *p2)
  {
  	const struct clock_entry *c1 = p1;
  	const struct clock_entry *c2 = p2;
  
  	if (c1->seq == c2->seq)
  		log_err("cs: bug in atomic sequence!\n");
  
  	return c1->seq - c2->seq;
  }
  
  int fio_monotonic_clocktest(int debug)
  {
  	struct clock_thread *cthreads;
  	unsigned int nr_cpus = cpus_online();
  	struct clock_entry *entries;
  	unsigned long nr_entries, tentries, failed = 0;
  	struct clock_entry *prev, *this;
  	uint32_t seq = 0;
  	unsigned int i;
  
  	if (debug) {
  		log_info("cs: reliable_tsc: %s\n", tsc_reliable ? "yes" : "no");
  
  #ifdef FIO_INC_DEBUG
  		fio_debug |= 1U << FD_TIME;
  #endif
  		nr_entries = CLOCK_ENTRIES_DEBUG;
  	} else
  		nr_entries = CLOCK_ENTRIES_TEST;
  
  	calibrate_cpu_clock();
  
  	if (debug) {
  #ifdef FIO_INC_DEBUG
  		fio_debug &= ~(1U << FD_TIME);
  #endif
  	}
  
  	cthreads = malloc(nr_cpus * sizeof(struct clock_thread));
  	tentries = nr_entries * nr_cpus;
  	entries = malloc(tentries * sizeof(struct clock_entry));
  
  	if (debug)
  		log_info("cs: Testing %u CPUs\n", nr_cpus);
  
  	for (i = 0; i < nr_cpus; i++) {
  		struct clock_thread *t = &cthreads[i];
  
  		t->cpu = i;
  		t->debug = debug;
  		t->seq = &seq;
  		t->nr_entries = nr_entries;
  		t->entries = &entries[i * nr_entries];
  		pthread_mutex_init(&t->lock, NULL);
  		pthread_mutex_init(&t->started, NULL);
  		pthread_mutex_lock(&t->lock);
  		if (pthread_create(&t->thread, NULL, clock_thread_fn, t)) {
  			failed++;
  			nr_cpus = i;
  			break;
  		}
  	}
  
  	for (i = 0; i < nr_cpus; i++) {
  		struct clock_thread *t = &cthreads[i];
  
  		pthread_mutex_lock(&t->started);
  	}
  
  	for (i = 0; i < nr_cpus; i++) {
  		struct clock_thread *t = &cthreads[i];
  
  		pthread_mutex_unlock(&t->lock);
  	}
  
  	for (i = 0; i < nr_cpus; i++) {
  		struct clock_thread *t = &cthreads[i];
  		void *ret;
  
  		pthread_join(t->thread, &ret);
  		if (ret)
  			failed++;
  	}
  	free(cthreads);
  
  	if (failed) {
  		if (debug)
  			log_err("Clocksource test: %lu threads failed\n", failed);
  		goto err;
  	}
  
  	qsort(entries, tentries, sizeof(struct clock_entry), clock_cmp);
  
  	for (failed = i = 0; i < tentries; i++) {
  		this = &entries[i];
  
  		if (!i) {
  			prev = this;
  			continue;
  		}
  
  		if (prev->tsc > this->tsc) {
  			uint64_t diff = prev->tsc - this->tsc;
  
  			if (!debug) {
  				failed++;
  				break;
  			}
  
  			log_info("cs: CPU clock mismatch (diff=%llu):\n",
  						(unsigned long long) diff);
  			log_info("\t CPU%3u: TSC=%llu, SEQ=%u\n", prev->cpu, (unsigned long long) prev->tsc, prev->seq);
  			log_info("\t CPU%3u: TSC=%llu, SEQ=%u\n", this->cpu, (unsigned long long) this->tsc, this->seq);
  			failed++;
  		}
  
  		prev = this;
  	}
  
  	if (debug) {
  		if (failed)
  			log_info("cs: Failed: %lu\n", failed);
  		else
  			log_info("cs: Pass!\n");
  	}
  err:
  	free(entries);
  	return !!failed;
  }
  
  #else /* defined(FIO_HAVE_CPU_AFFINITY) && defined(ARCH_HAVE_CPU_CLOCK) */
  
  int fio_monotonic_clocktest(int debug)
  {
  	if (debug)
  		log_info("cs: current platform does not support CPU clocks\n");
  	return 1;
  }
  
  #endif
  