X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=gettime.c;h=08d2d2b3b1205a56543ec6aef00e52b37711d622;hp=d78cf6d0ba9281a36ec286c5e6e87843fb49e360;hb=c223da83e253b0057bb029bf4fbb55a05844215c;hpb=5ec10eaad3b09875b91e19a20bbdfa06f2117562

diff --git a/gettime.c b/gettime.c
index d78cf6d0..08d2d2b3 100644
--- a/gettime.c
+++ b/gettime.c
@@ -3,24 +3,35 @@
  */
 
 #include <unistd.h>
+#include <math.h>
 #include <sys/time.h>
 
 #include "fio.h"
+#include "smalloc.h"
 
 #include "hash.h"
 
-static int clock_gettime_works;
+static unsigned long cycles_per_usec;
+static struct timeval last_tv;
+static unsigned long last_cycles;
+static int last_tv_valid;
+
+static struct timeval *fio_tv;
+int fio_gtod_offload = 0;
+int fio_gtod_cpu = -1;
+
+enum fio_cs fio_clock_source = CS_GTOD;
 
 #ifdef FIO_DEBUG_TIME
 
 #define HASH_BITS	8
 #define HASH_SIZE	(1 << HASH_BITS)
 
-static struct list_head hash[HASH_SIZE];
+static struct flist_head hash[HASH_SIZE];
 static int gtod_inited;
 
 struct gtod_log {
-	struct list_head list;
+	struct flist_head list;
 	void *caller;
 	unsigned long calls;
 };
@@ -28,10 +39,11 @@ struct gtod_log {
 static struct gtod_log *find_hash(void *caller)
 {
 	unsigned long h = hash_ptr(caller, HASH_BITS);
-	struct list_head *entry;
+	struct flist_head *entry;
 
-	list_for_each(entry, &hash[h]) {
-		struct gtod_log *log = list_entry(entry, struct gtod_log, list);
+	flist_for_each(entry, &hash[h]) {
+		struct gtod_log *log = flist_entry(entry, struct gtod_log,
+									list);
 
 		if (log->caller == caller)
 			return log;
@@ -48,12 +60,12 @@ static struct gtod_log *find_log(void *caller)
 		unsigned long h;
 
 		log = malloc(sizeof(*log));
-		INIT_LIST_HEAD(&log->list);
+		INIT_FLIST_HEAD(&log->list);
 		log->caller = caller;
 		log->calls = 0;
 
 		h = hash_ptr(caller, HASH_BITS);
-		list_add_tail(&log->list, &hash[h]);
+		flist_add_tail(&log->list, &hash[h]);
 	}
 
 	return log;
@@ -74,11 +86,11 @@ static void fio_exit fio_dump_gtod(void)
 	int i;
 
 	for (i = 0; i < HASH_SIZE; i++) {
-		struct list_head *entry;
+		struct flist_head *entry;
 		struct gtod_log *log;
 
-		list_for_each(entry, &hash[i]) {
-			log = list_entry(entry, struct gtod_log, list);
+		flist_for_each(entry, &hash[i]) {
+			log = flist_entry(entry, struct gtod_log, list);
 
 			printf("function %p, calls %lu\n", log->caller,
 								log->calls);
@@ -94,7 +106,7 @@ static void fio_init gtod_init(void)
 	int i;
 
 	for (i = 0; i < HASH_SIZE; i++)
-		INIT_LIST_HEAD(&hash[i]);
+		INIT_FLIST_HEAD(&hash[i]);
 
 	gtod_inited = 1;
 }
@@ -113,18 +125,136 @@ void fio_gettime(struct timeval *tp, void fio_unused *caller)
 
 	gtod_log_caller(caller);
 #endif
-	if (!clock_gettime_works) {
-gtod:
+	if (fio_tv) {
+		memcpy(tp, fio_tv, sizeof(*tp));
+		return;
+	}
+
+	switch (fio_clock_source) {
+	case CS_GTOD:
 		gettimeofday(tp, NULL);
-	} else {
+		break;
+	case CS_CGETTIME: {
 		struct timespec ts;
 
-		if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
-			clock_gettime_works = 0;
-			goto gtod;
+		if (clock_gettime(CLOCK_REALTIME, &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;
+		}
+#ifdef ARCH_HAVE_CPU_CLOCK
+	case CS_CPUCLOCK: {
+		unsigned long long usecs, t;
+
+		t = get_cpu_clock();
+		if (t < last_cycles) {
+			dprint(FD_TIME, "CPU clock going back in time\n");
+			t = last_cycles;
+		}
+
+		usecs = t / cycles_per_usec;
+		tp->tv_sec = usecs / 1000000;
+		tp->tv_usec = usecs % 1000000;
+		last_cycles = t;
+		break;
+		}
+#endif
+	default:
+		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));
+}
+
+static unsigned long get_cycles_per_usec(void)
+{
+	struct timeval s, e;
+	unsigned long long c_s, c_e;
+
+	gettimeofday(&s, NULL);
+	c_s = get_cpu_clock();
+	do {
+		unsigned long long elapsed;
+
+		gettimeofday(&e, NULL);
+		elapsed = utime_since(&s, &e);
+		if (elapsed >= 10) {
+			c_e = get_cpu_clock();
+			break;
+		}
+	} while (1);
+
+	return c_e - c_s;
+}
+
+void fio_clock_init(void)
+{
+	double delta, mean, S;
+	unsigned long avg, cycles[10];
+	int i, samples;
+
+	last_tv_valid = 0;
+
+	cycles[0] = get_cycles_per_usec();
+	S = delta = mean = 0.0;
+	for (i = 0; i < 10; i++) {
+		cycles[i] = get_cycles_per_usec();
+		delta = cycles[i] - mean;
+		if (delta) {
+			mean += delta / (i + 1.0);
+			S += delta * (cycles[i] - mean);
+		}
+	}
+
+	S = sqrt(S / (10 - 1.0));
+
+	samples = avg = 0;
+	for (i = 0; i < 10; i++) {
+		double this = cycles[i];
+
+		if ((max(this, mean) - min(this, mean)) > S)
+			continue;
+		samples++;
+		avg += this;
+	}
+
+	S /= 10.0;
+	mean /= 10.0;
+
+	for (i = 0; i < 10; i++)
+		dprint(FD_TIME, "cycles[%d]=%lu\n", i, cycles[i] / 10);
+
+	avg /= (samples * 10);
+	dprint(FD_TIME, "avg: %lu\n", avg);
+	dprint(FD_TIME, "mean=%f, S=%f\n", mean, S);
+
+	cycles_per_usec = avg;
+}
+
+void fio_gtod_init(void)
+{
+	fio_tv = smalloc(sizeof(struct timeval));
+	assert(fio_tv);
+}
+
+void fio_gtod_update(void)
+{
+	gettimeofday(fio_tv, NULL);
 }