X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=gettime.c;h=5ceb809de3ae9247a5cc7d3e2557b062541fc73f;hp=15356b1b9227c2b92f7676aae124664647f0e5d1;hb=aad918e47d119eb2043311f1a2a45ce109c047d1;hpb=ecc35cf45f60e658856c6f0cbd5b7785753981bb

diff --git a/gettime.c b/gettime.c
index 15356b1b..5ceb809d 100644
--- a/gettime.c
+++ b/gettime.c
@@ -11,19 +11,32 @@
 #include "smalloc.h"
 
 #include "hash.h"
+#include "os/os.h"
 
-#ifdef ARCH_HAVE_CPU_CLOCK
+#if defined(ARCH_HAVE_CPU_CLOCK) && !defined(ARCH_CPU_CLOCK_CYCLES_PER_USEC)
 static unsigned long cycles_per_usec;
-static unsigned long last_cycles;
+static unsigned long inv_cycles_per_usec;
+static uint64_t max_cycles_for_mult;
+static unsigned long long cycles_start, cycles_wrap;
 #endif
-static struct timeval last_tv;
-static int last_tv_valid;
+int tsc_reliable = 0;
 
-static struct timeval *fio_tv;
-int fio_gtod_offload = 0;
-int fio_gtod_cpu = -1;
+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 = CS_GTOD;
+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
 
@@ -55,7 +68,7 @@ static struct gtod_log *find_hash(void *caller)
 	return NULL;
 }
 
-static struct gtod_log *find_log(void *caller)
+static void inc_caller(void *caller)
 {
 	struct gtod_log *log = find_hash(caller);
 
@@ -71,16 +84,13 @@ static struct gtod_log *find_log(void *caller)
 		flist_add_tail(&log->list, &hash[h]);
 	}
 
-	return log;
+	log->calls++;
 }
 
 static void gtod_log_caller(void *caller)
 {
-	if (gtod_inited) {
-		struct gtod_log *log = find_log(caller);
-
-		log->calls++;
-	}
+	if (gtod_inited)
+		inc_caller(caller);
 }
 
 static void fio_exit fio_dump_gtod(void)
@@ -116,35 +126,30 @@ static void fio_init gtod_init(void)
 
 #endif /* FIO_DEBUG_TIME */
 
-#ifdef FIO_DEBUG_TIME
-void fio_gettime(struct timeval *tp, void *caller)
+#ifdef CONFIG_CLOCK_GETTIME
+static int fill_clock_gettime(struct timespec *ts)
+{
+#ifdef CONFIG_CLOCK_MONOTONIC
+	return clock_gettime(CLOCK_MONOTONIC, ts);
 #else
-void fio_gettime(struct timeval *tp, void fio_unused *caller)
+	return clock_gettime(CLOCK_REALTIME, ts);
 #endif
-{
-#ifdef FIO_DEBUG_TIME
-	if (!caller)
-		caller = __builtin_return_address(0);
-
-	gtod_log_caller(caller);
+}
 #endif
-	if (fio_tv) {
-		memcpy(tp, fio_tv, sizeof(*tp));
-		return;
-	}
 
+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;
 
-#ifdef FIO_HAVE_CLOCK_MONOTONIC
-		if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
-#else
-		if (clock_gettime(CLOCK_REALTIME, &ts) < 0) {
-#endif
+		if (fill_clock_gettime(&ts) < 0) {
 			log_err("fio: clock_gettime fails\n");
 			assert(0);
 		}
@@ -153,20 +158,39 @@ void fio_gettime(struct timeval *tp, void fio_unused *caller)
 		tp->tv_usec = ts.tv_nsec / 1000;
 		break;
 		}
+#endif
 #ifdef ARCH_HAVE_CPU_CLOCK
 	case CS_CPUCLOCK: {
-		unsigned long long usecs, t;
+		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();
-		if (t < last_cycles) {
-			dprint(FD_TIME, "CPU clock going back in time\n");
-			t = last_cycles;
+		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;
 		}
 
-		usecs = t / cycles_per_usec;
+		t -= cycles_start;
+		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;
-		last_cycles = t;
 		break;
 		}
 #endif
@@ -174,53 +198,68 @@ void fio_gettime(struct timeval *tp, void fio_unused *caller)
 		log_err("fio: invalid clock source %d\n", fio_clock_source);
 		break;
 	}
+}
 
-	/*
-	 * If Linux is using the tsc clock on non-synced processors,
-	 * sometimes time can appear to drift backwards. Fix that up.
-	 */
-	if (last_tv_valid) {
-		if (tp->tv_sec < last_tv.tv_sec)
-			tp->tv_sec = last_tv.tv_sec;
-		else if (last_tv.tv_sec == tp->tv_sec &&
-			 tp->tv_usec < last_tv.tv_usec)
-			tp->tv_usec = last_tv.tv_usec;
-	}
-	last_tv_valid = 1;
-	memcpy(&last_tv, tp, sizeof(*tp));
+#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);
 }
 
-#ifdef ARCH_HAVE_CPU_CLOCK
+#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;
-	unsigned long long c_s, c_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);
 
-	gettimeofday(&s, NULL);
 	c_s = get_cpu_clock();
 	do {
-		unsigned long long elapsed;
+		uint64_t elapsed;
+
+		__fio_gettime(&e);
 
-		gettimeofday(&e, NULL);
 		elapsed = utime_since(&s, &e);
-		if (elapsed >= 10) {
+		if (elapsed >= 1280) {
 			c_e = get_cpu_clock();
 			break;
 		}
 	} while (1);
 
-	return c_e - c_s;
+	fio_clock_source = old_cs;
+	return (c_e - c_s + 127) >> 7;
 }
 
-static void calibrate_cpu_clock(void)
+#define NR_TIME_ITERS	50
+
+static int calibrate_cpu_clock(void)
 {
 	double delta, mean, S;
-	unsigned long avg, cycles[10];
+	uint64_t avg, cycles[NR_TIME_ITERS];
 	int i, samples;
 
 	cycles[0] = get_cycles_per_usec();
 	S = delta = mean = 0.0;
-	for (i = 0; i < 10; i++) {
+	for (i = 0; i < NR_TIME_ITERS; i++) {
 		cycles[i] = get_cycles_per_usec();
 		delta = cycles[i] - mean;
 		if (delta) {
@@ -229,10 +268,17 @@ static void calibrate_cpu_clock(void)
 		}
 	}
 
-	S = sqrt(S / (10 - 1.0));
+	/*
+	 * 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));
 
 	samples = avg = 0;
-	for (i = 0; i < 10; i++) {
+	for (i = 0; i < NR_TIME_ITERS; i++) {
 		double this = cycles[i];
 
 		if ((fmax(this, mean) - fmin(this, mean)) > S)
@@ -241,38 +287,372 @@ static void calibrate_cpu_clock(void)
 		avg += this;
 	}
 
-	S /= 10.0;
+	S /= (double) NR_TIME_ITERS;
 	mean /= 10.0;
 
-	for (i = 0; i < 10; i++)
-		dprint(FD_TIME, "cycles[%d]=%lu\n", i, cycles[i] / 10);
+	for (i = 0; i < NR_TIME_ITERS; i++)
+		dprint(FD_TIME, "cycles[%d]=%llu\n", i,
+					(unsigned long long) cycles[i] / 10);
 
-	avg /= (samples * 10);
-	dprint(FD_TIME, "avg: %lu\n", avg);
+	avg /= samples;
+	avg = (avg + 5) / 10;
+	dprint(FD_TIME, "avg: %llu\n", (unsigned long long) avg);
 	dprint(FD_TIME, "mean=%f, S=%f\n", 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);
+	cycles_start = get_cpu_clock();
+	dprint(FD_TIME, "cycles_start=%llu\n", cycles_start);
+	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
-static void calibrate_cpu_clock(void)
+void fio_local_clock_init(int is_thread)
 {
 }
 #endif
 
 void fio_clock_init(void)
 {
-	last_tv_valid = 0;
-	calibrate_cpu_clock();
+	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");
 }
 
-void fio_gtod_init(void)
+uint64_t utime_since(const struct timeval *s, const struct timeval *e)
 {
-	fio_tv = smalloc(sizeof(struct timeval));
-	assert(fio_tv);
+	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;
 }
 
-void fio_gtod_update(void)
+uint64_t utime_since_now(const struct timeval *s)
 {
-	gettimeofday(fio_tv, NULL);
+	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;
+
+	memset(&cpu_mask, 0, sizeof(cpu_mask));
+	fio_cpu_set(&cpu_mask, t->cpu);
+
+	if (fio_setaffinity(gettid(), cpu_mask) == -1) {
+		log_err("clock setaffinity failed\n");
+		return (void *) 1;
+	}
+
+	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)
+		return (void *) 1;
+
+	return NULL;
+}
+
+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