diff --git a/fio-time.c b/fio-time.c
new file mode 100644
index 0000000..5246263
--- /dev/null
+++ b/fio-time.c
@@ -0,0 +1,122 @@
+#include <time.h>
+#include <sys/time.h>
+
+#include "fio.h"
+
+unsigned long utime_since(struct timeval *s, struct timeval *e)
+{
+	double sec, usec;
+
+	sec = e->tv_sec - s->tv_sec;
+	usec = e->tv_usec - s->tv_usec;
+	if (sec > 0 && usec < 0) {
+		sec--;
+		usec += 1000000;
+	}
+
+	sec *= (double) 1000000;
+
+	return sec + usec;
+}
+
+static unsigned long utime_since_now(struct timeval *s)
+{
+	struct timeval t;
+
+	gettimeofday(&t, NULL);
+	return utime_since(s, &t);
+}
+
+unsigned long mtime_since(struct timeval *s, struct timeval *e)
+{
+	double sec, usec;
+
+	sec = e->tv_sec - s->tv_sec;
+	usec = e->tv_usec - s->tv_usec;
+	if (sec > 0 && usec < 0) {
+		sec--;
+		usec += 1000000;
+	}
+
+	sec *= (double) 1000;
+	usec /= (double) 1000;
+
+	return sec + usec;
+}
+
+unsigned long mtime_since_now(struct timeval *s)
+{
+	struct timeval t;
+
+	gettimeofday(&t, NULL);
+	return mtime_since(s, &t);
+}
+
+unsigned long time_since_now(struct timeval *s)
+{
+	return mtime_since_now(s) / 1000;
+}
+
+/*
+ * busy looping version for the last few usec
+ */
+static void __usec_sleep(unsigned int usec)
+{
+	struct timeval start;
+
+	gettimeofday(&start, NULL);
+	while (utime_since_now(&start) < usec)
+		nop;
+}
+
+void usec_sleep(struct thread_data *td, unsigned long usec)
+{
+	struct timespec req, rem;
+
+	req.tv_sec = usec / 1000000;
+	req.tv_nsec = usec * 1000 - req.tv_sec * 1000000;
+
+	do {
+		if (usec < 5000) {
+			__usec_sleep(usec);
+			break;
+		}
+
+		rem.tv_sec = rem.tv_nsec = 0;
+		if (nanosleep(&req, &rem) < 0)
+			break;
+
+		if ((rem.tv_sec + rem.tv_nsec) == 0)
+			break;
+
+		req.tv_nsec = rem.tv_nsec;
+		req.tv_sec = rem.tv_sec;
+
+		usec = rem.tv_sec * 1000000 + rem.tv_nsec / 1000;
+	} while (!td->terminate);
+}
+
+void rate_throttle(struct thread_data *td, unsigned long time_spent,
+		   unsigned int bytes)
+{
+	unsigned long usec_cycle;
+
+	if (!td->rate)
+		return;
+
+	usec_cycle = td->rate_usec_cycle * (bytes / td->min_bs);
+
+	if (time_spent < usec_cycle) {
+		unsigned long s = usec_cycle - time_spent;
+
+		td->rate_pending_usleep += s;
+		if (td->rate_pending_usleep >= 100000) {
+			usec_sleep(td, td->rate_pending_usleep);
+			td->rate_pending_usleep = 0;
+		}
+	} else {
+		long overtime = time_spent - usec_cycle;
+
+		td->rate_pending_usleep -= overtime;
+	}
+}