time: use timespec instead of timeval.

It's a superset of struct timeval.  It's also a bit trickier, since we
need -lrt on Linux to use clock_gettime(), and also we can't just cram the
time into a u64 for multiply and divide.

ccan/time/_info

@@ -17,7 +17,7 @@
  *
  *	int main(int argc, char *argv[])
  *	{
- *		struct timeval t;
+ *		struct timespec t;
  *
  *		if (argc != 2)
  *			errx(1, "Usage: %s <diff in millisec>", argv[0]);
@@ -28,8 +28,8 @@
  *		else
  *			t = time_add(t, time_from_msec(atol(argv[1])));
  *
- *		printf("%lu.%06u\n",
- *		       (unsigned long)t.tv_sec, (unsigned)t.tv_usec);
+ *		printf("%lu.%09u\n",
+ *		       (unsigned long)t.tv_sec, (unsigned)t.tv_nsec);
  *		return 0;
  *	}
  */
@@ -43,5 +43,12 @@ int main(int argc, char *argv[])
 		return 0;
 	}
 
+#if HAVE_CLOCK_GETTIME_IN_LIBRT
+	if (strcmp(argv[1], "libs") == 0) {
+		printf("rt\n");
+		return 0;
+	}
+#endif
+
 	return 1;
 }

ccan/time/test/run.c

@@ -4,9 +4,9 @@
 
 int main(void)
 {
-	struct timeval t1, t2, t3, zero = { 0, 0 };
+	struct timespec t1, t2, t3, zero = { 0, 0 };
 
-	plan_tests(46);
+	plan_tests(58);
 
 	/* Test time_now */
 	t1 = time_now();
@@ -14,11 +14,11 @@ int main(void)
 
 	/* Test time_sub. */
 	t3 = time_sub(t2, t1);
-	ok1(t3.tv_sec > 0 || t3.tv_usec >= 0);
+	ok1(t3.tv_sec > 0 || t3.tv_nsec >= 0);
 	t3 = time_sub(t2, t2);
-	ok1(t3.tv_sec == 0 && t3.tv_usec == 0);
+	ok1(t3.tv_sec == 0 && t3.tv_nsec == 0);
 	t3 = time_sub(t1, t1);
-	ok1(t3.tv_sec == 0 && t3.tv_usec == 0);
+	ok1(t3.tv_sec == 0 && t3.tv_nsec == 0);
 
 	/* Test time_eq */
 	ok1(time_eq(t1, t1));
@@ -28,7 +28,7 @@ int main(void)
 
 	/* Make sure t2 > t1. */
 	t3.tv_sec = 0;
-	t3.tv_usec = 1;
+	t3.tv_nsec = 1;
 	t2 = time_add(t2, t3);
 
 	/* Test time_less and time_greater. */
@@ -38,7 +38,7 @@ int main(void)
 	ok1(time_greater(t2, t1));
 	ok1(!time_less(t2, t1));
 	t3.tv_sec = 0;
-	t3.tv_usec = 999999;
+	t3.tv_nsec = 999999999;
 	t2 = time_add(t2, t3);
 	ok1(!time_eq(t1, t2));
 	ok1(!time_greater(t1, t2));
@@ -54,58 +54,89 @@ int main(void)
 	/* time_from_msec / time_to_msec */
 	t3 = time_from_msec(500);
 	ok1(t3.tv_sec == 0);
-	ok1(t3.tv_usec == 500000);
+	ok1(t3.tv_nsec == 500000000);
 	ok1(time_to_msec(t3) == 500);
 
 	t3 = time_from_msec(1000);
 	ok1(t3.tv_sec == 1);
-	ok1(t3.tv_usec == 0);
+	ok1(t3.tv_nsec == 0);
 	ok1(time_to_msec(t3) == 1000);
 
 	t3 = time_from_msec(1500);
 	ok1(t3.tv_sec == 1);
-	ok1(t3.tv_usec == 500000);
+	ok1(t3.tv_nsec == 500000000);
 	ok1(time_to_msec(t3) == 1500);
 
 	/* time_from_usec */
 	t3 = time_from_usec(500000);
 	ok1(t3.tv_sec == 0);
-	ok1(t3.tv_usec == 500000);
+	ok1(t3.tv_nsec == 500000000);
 	ok1(time_to_usec(t3) == 500000);
 
 	t3 = time_from_usec(1000000);
 	ok1(t3.tv_sec == 1);
-	ok1(t3.tv_usec == 0);
+	ok1(t3.tv_nsec == 0);
 	ok1(time_to_usec(t3) == 1000000);
 
 	t3 = time_from_usec(1500000);
 	ok1(t3.tv_sec == 1);
-	ok1(t3.tv_usec == 500000);
+	ok1(t3.tv_nsec == 500000000);
 	ok1(time_to_usec(t3) == 1500000);
 
+	/* time_from_nsec */
+	t3 = time_from_nsec(500000000);
+	ok1(t3.tv_sec == 0);
+	ok1(t3.tv_nsec == 500000000);
+	ok1(time_to_nsec(t3) == 500000000);
+
+	t3 = time_from_nsec(1000000000);
+	ok1(t3.tv_sec == 1);
+	ok1(t3.tv_nsec == 0);
+	ok1(time_to_nsec(t3) == 1000000000);
+
+	t3 = time_from_nsec(1500000000);
+	ok1(t3.tv_sec == 1);
+	ok1(t3.tv_nsec == 500000000);
+	ok1(time_to_nsec(t3) == 1500000000);
+
 	/* Test wrapunder */
 	t3 = time_sub(time_sub(t2, time_from_msec(500)), time_from_msec(500));
 	ok1(t3.tv_sec == t2.tv_sec - 1);
-	ok1(t3.tv_usec == t2.tv_usec);
+	ok1(t3.tv_nsec == t2.tv_nsec);
 
 	/* time_divide and time_multiply */
-	t1.tv_usec = 100;
+	t1.tv_nsec = 100;
 	t1.tv_sec = 100;
 
 	t3 = time_divide(t1, 2);
 	ok1(t3.tv_sec == 50);
-	ok1(t3.tv_usec == 50);
+	ok1(t3.tv_nsec == 50);
 
 	t3 = time_divide(t1, 100);
 	ok1(t3.tv_sec == 1);
-	ok1(t3.tv_usec == 1);
+	ok1(t3.tv_nsec == 1);
 
 	t3 = time_multiply(t3, 100);
 	ok1(time_eq(t3, t1));
 
 	t3 = time_divide(t1, 200);
 	ok1(t3.tv_sec == 0);
-	ok1(t3.tv_usec == 500000);
+	ok1(t3.tv_nsec == 500000000);
+
+	/* Divide by huge number. */
+	t1.tv_sec = (1U << 31) - 1;
+	t1.tv_nsec = 999999999;
+	t2 = time_divide(t1, 1 << 30);
+	/* Allow us to round either way. */
+	ok1((t2.tv_sec == 2 && t2.tv_nsec == 0)
+	    || (t2.tv_sec == 1 && t2.tv_nsec == 999999999));
+
+	/* Multiply by huge number. */
+	t1.tv_sec = 0;
+	t1.tv_nsec = 1;
+	t2 = time_multiply(t1, 1UL << 31);
+	ok1(t2.tv_sec == 2);
+	ok1(t2.tv_nsec == 147483648);
 
 	return exit_status();
 }

ccan/time/time.c

@@ -3,106 +3,178 @@
 #include <stdlib.h>
 #include <assert.h>
 
-struct timeval time_now(void)
+#if !HAVE_CLOCK_GETTIME && !HAVE_CLOCK_GETTIME_IN_LIBRT
+#include <sys/time.h>
+
+struct timespec time_now(void)
 {
 	struct timeval now;
+	struct timespec ret;
 	gettimeofday(&now, NULL);
-	return now;
+	ret.tv_sec = now.tv_sec;
+	ret.tv_nsec = now.tv_usec * 1000;
+	return ret;
+}
+#else
+#include <time.h>
+struct timespec time_now(void)
+{
+	struct timespec ret;
+	clock_gettime(CLOCK_REALTIME, &ret);
+	return ret;
 }
+#endif /* HAVE_CLOCK_GETTIME || HAVE_CLOCK_GETTIME_IN_LIBRT */
 
-bool time_greater(struct timeval a, struct timeval b)
+bool time_greater(struct timespec a, struct timespec b)
 {
 	if (a.tv_sec > b.tv_sec)
 		return true;
 	else if (a.tv_sec < b.tv_sec)
 		 return false;
 
-	return a.tv_usec > b.tv_usec;
+	return a.tv_nsec > b.tv_nsec;
 }
 
-bool time_less(struct timeval a, struct timeval b)
+bool time_less(struct timespec a, struct timespec b)
 {
 	if (a.tv_sec < b.tv_sec)
 		return true;
 	else if (a.tv_sec > b.tv_sec)
 		 return false;
 
-	return a.tv_usec < b.tv_usec;
+	return a.tv_nsec < b.tv_nsec;
 }
 
-bool time_eq(struct timeval a, struct timeval b)
+bool time_eq(struct timespec a, struct timespec b)
 {
-	return a.tv_sec == b.tv_sec && a.tv_usec == b.tv_usec;
+	return a.tv_sec == b.tv_sec && a.tv_nsec == b.tv_nsec;
 }
 
-struct timeval time_sub(struct timeval recent, struct timeval old)
+struct timespec time_sub(struct timespec recent, struct timespec old)
 {
-	struct timeval diff;
+	struct timespec diff;
 
 	diff.tv_sec = recent.tv_sec - old.tv_sec;
-	if (old.tv_usec > recent.tv_usec) {
+	if (old.tv_nsec > recent.tv_nsec) {
 		diff.tv_sec--;
-		diff.tv_usec = 1000000 + recent.tv_usec - old.tv_usec;
+		diff.tv_nsec = 1000000000 + recent.tv_nsec - old.tv_nsec;
 	} else
-		diff.tv_usec = recent.tv_usec - old.tv_usec;
+		diff.tv_nsec = recent.tv_nsec - old.tv_nsec;
 
 	assert(diff.tv_sec >= 0);
 	return diff;
 }
 
-struct timeval time_add(struct timeval a, struct timeval b)
+struct timespec time_add(struct timespec a, struct timespec b)
 {
-	struct timeval sum;
+	struct timespec sum;
 
 	sum.tv_sec = a.tv_sec + b.tv_sec;
-	sum.tv_usec = a.tv_usec + b.tv_usec;
-	if (sum.tv_usec > 1000000) {
+	sum.tv_nsec = a.tv_nsec + b.tv_nsec;
+	if (sum.tv_nsec >= 1000000000) {
 		sum.tv_sec++;
-		sum.tv_usec -= 1000000;
+		sum.tv_nsec -= 1000000000;
 	}
 	return sum;
 }
 
-struct timeval time_divide(struct timeval t, unsigned long div)
+struct timespec time_divide(struct timespec t, unsigned long div)
 {
-	return time_from_usec(time_to_usec(t) / div);
+	struct timespec res;
+	uint64_t rem, ns;
+
+	/* Dividing seconds is simple. */
+	res.tv_sec = t.tv_sec / div;
+	rem = t.tv_sec % div;
+
+	/* If we can't fit remainder * 1,000,000,000 in 64 bits? */
+#if 0 /* ilog is great, but we use fp for multiply anyway. */
+	bits = ilog64(rem);
+	if (bits + 30 >= 64) {
+		/* Reduce accuracy slightly */
+		rem >>= (bits - (64 - 30));
+		div >>= (bits - (64 - 30));
+	}
+#endif
+	if (rem & ~(((uint64_t)1 << 30) - 1)) {
+		/* FIXME: fp is cheating! */
+		double nsec = rem * 1000000000.0 + t.tv_nsec;
+		res.tv_nsec = nsec / div;
+	} else {
+		ns = rem * 1000000000 + t.tv_nsec;
+		res.tv_nsec = ns / div;
+	}
+	return res;
 }
 
-struct timeval time_multiply(struct timeval t, unsigned long mult)
+struct timespec time_multiply(struct timespec t, unsigned long mult)
 {
-	return time_from_usec(time_to_usec(t) * mult);
+	struct timespec res;
+
+	/* Are we going to overflow if we multiply nsec? */
+	if (mult & ~((1UL << 30) - 1)) {
+		/* FIXME: fp is cheating! */
+		double nsec = (double)t.tv_nsec * mult;
+
+		res.tv_sec = nsec / 1000000000.0;
+		res.tv_nsec = nsec - (res.tv_sec * 1000000000.0);
+	} else {
+		uint64_t nsec = t.tv_nsec * mult;
+
+		res.tv_nsec = nsec % 1000000000;
+		res.tv_sec = nsec / 1000000000;
+	}
+	res.tv_sec += t.tv_sec * mult;
+	return res;
 }
 
-uint64_t time_to_msec(struct timeval t)
+uint64_t time_to_msec(struct timespec t)
 {
 	uint64_t msec;
 
-	msec = t.tv_usec / 1000 + (uint64_t)t.tv_sec * 1000;
+	msec = t.tv_nsec / 1000000 + (uint64_t)t.tv_sec * 1000;
 	return msec;
 }
 
-uint64_t time_to_usec(struct timeval t)
+uint64_t time_to_usec(struct timespec t)
 {
 	uint64_t usec;
 
-	usec = t.tv_usec + (uint64_t)t.tv_sec * 1000000;
+	usec = t.tv_nsec / 1000 + (uint64_t)t.tv_sec * 1000000;
 	return usec;
 }
 
-struct timeval time_from_msec(uint64_t msec)
+uint64_t time_to_nsec(struct timespec t)
 {
-	struct timeval t;
+	uint64_t nsec;
 
-	t.tv_usec = (msec % 1000) * 1000;
+	nsec = t.tv_nsec + (uint64_t)t.tv_sec * 1000000000;
+	return nsec;
+}
+
+struct timespec time_from_msec(uint64_t msec)
+{
+	struct timespec t;
+
+	t.tv_nsec = (msec % 1000) * 1000000;
 	t.tv_sec = msec / 1000;
 	return t;
 }
 
-struct timeval time_from_usec(uint64_t usec)
+struct timespec time_from_usec(uint64_t usec)
 {
-	struct timeval t;
+	struct timespec t;
 
-	t.tv_usec = usec % 1000000;
+	t.tv_nsec = (usec % 1000000) * 1000;
 	t.tv_sec = usec / 1000000;
 	return t;
 }
+
+struct timespec time_from_nsec(uint64_t nsec)
+{
+	struct timespec t;
+
+	t.tv_nsec = nsec % 1000000000;
+	t.tv_sec = nsec / 1000000000;
+	return t;
+}

ccan/time/time.h

@@ -3,6 +3,14 @@
 #define CCAN_TIME_H
 #include "config.h"
 #include <sys/time.h>
+#if HAVE_STRUCT_TIMESPEC
+#include <time.h>
+#else
+struct timespec {
+	time_t   tv_sec;        /* seconds */
+	long     tv_nsec;       /* nanoseconds */
+};
+#endif
 #include <stdint.h>
 #include <stdbool.h>
 
@@ -12,7 +20,7 @@
  * Example:
  *	printf("Now is %lu seconds since epoch\n", (long)time_now().tv_sec);
  */
-struct timeval time_now(void);
+struct timespec time_now(void);
 
 /**
  * time_greater - is a after b?
@@ -20,13 +28,13 @@ struct timeval time_now(void);
  * @b: another time.
  *
  * Example:
- *	static bool timed_out(const struct timeval *start)
+ *	static bool timed_out(const struct timespec *start)
  *	{
  *	#define TIMEOUT time_from_msec(1000)
  *		return time_greater(time_now(), time_add(*start, TIMEOUT));
  *	}
  */
-bool time_greater(struct timeval a, struct timeval b);
+bool time_greater(struct timespec a, struct timespec b);
 
 /**
  * time_less - is a before b?
@@ -34,13 +42,13 @@ bool time_greater(struct timeval a, struct timeval b);
  * @b: another time.
  *
  * Example:
- *	static bool still_valid(const struct timeval *start)
+ *	static bool still_valid(const struct timespec *start)
  *	{
  *	#define TIMEOUT time_from_msec(1000)
  *		return time_less(time_now(), time_add(*start, TIMEOUT));
  *	}
  */
-bool time_less(struct timeval a, struct timeval b);
+bool time_less(struct timespec a, struct timespec b);
 
 /**
  * time_eq - is a equal to b?
@@ -54,7 +62,7 @@ bool time_less(struct timeval a, struct timeval b);
  *	// Can we fork in under a microsecond?
  *	static bool fast_fork(void)
  *	{
- *		struct timeval start = time_now();
+ *		struct timespec start = time_now();
  *		if (fork() != 0) {
  *			exit(0);
  *		}
@@ -62,22 +70,22 @@ bool time_less(struct timeval a, struct timeval b);
  *		return time_eq(start, time_now());
  *	}
  */
-bool time_eq(struct timeval a, struct timeval b);
+bool time_eq(struct timespec a, struct timespec b);
 
 /**
  * time_sub - subtract two times
  * @recent: the larger (more recent) time.
  * @old: the smaller (less recent) time.
  *
- * This returns a well formed struct timeval.
+ * This returns a well formed struct timespec.
  *
  * Example:
- *	static bool was_recent(const struct timeval *start)
+ *	static bool was_recent(const struct timespec *start)
  *	{
  *		return time_sub(time_now(), *start).tv_sec < 1;
  *	}
  */
-struct timeval time_sub(struct timeval recent, struct timeval old);
+struct timespec time_sub(struct timespec recent, struct timespec old);
 
 /**
  * time_add - add two times
@@ -88,12 +96,12 @@ struct timeval time_sub(struct timeval recent, struct timeval old);
  *
  * Example:
  *	// We do one every second.
- *	static struct timeval next_time(void)
+ *	static struct timespec next_time(void)
  *	{
  *		return time_add(time_now(), time_from_msec(1000));
  *	}
  */
-struct timeval time_add(struct timeval a, struct timeval b);
+struct timespec time_add(struct timespec a, struct timespec b);
 
 /**
  * time_divide - divide a time by a value.
@@ -102,9 +110,9 @@ struct timeval time_add(struct timeval a, struct timeval b);
  *
  * Example:
  *	// How long does it take to do a fork?
- *	static struct timeval forking_time(void)
+ *	static struct timespec forking_time(void)
  *	{
- *		struct timeval start = time_now();
+ *		struct timespec start = time_now();
  *		unsigned int i;
  *
  *		for (i = 0; i < 1000; i++) {
@@ -116,7 +124,7 @@ struct timeval time_add(struct timeval a, struct timeval b);
  *		return time_divide(time_sub(time_now(), start), i);
  *	}
  */
-struct timeval time_divide(struct timeval t, unsigned long div);
+struct timespec time_divide(struct timespec t, unsigned long div);
 
 /**
  * time_multiply - multiply a time by a value.
@@ -128,7 +136,7 @@ struct timeval time_divide(struct timeval t, unsigned long div);
  *	printf("Time to do 100000 forks would be %u sec\n",
  *	       (unsigned)time_multiply(forking_time(), 1000000).tv_sec);
  */
-struct timeval time_multiply(struct timeval t, unsigned long mult);
+struct timespec time_multiply(struct timespec t, unsigned long mult);
 
 /**
  * time_to_msec - return number of milliseconds
@@ -143,7 +151,7 @@ struct timeval time_multiply(struct timeval t, unsigned long mult);
  *	printf("Forking time is %u msec\n",
  *	       (unsigned)time_to_msec(forking_time()));
  */
-uint64_t time_to_msec(struct timeval t);
+uint64_t time_to_msec(struct timespec t);
 
 /**
  * time_to_usec - return number of microseconds
@@ -159,26 +167,86 @@ uint64_t time_to_msec(struct timeval t);
  *	       (unsigned)time_to_usec(forking_time()));
  *
  */
-uint64_t time_to_usec(struct timeval t);
+uint64_t time_to_usec(struct timespec t);
 
 /**
- * time_from_msec - convert milliseconds to a timeval
+ * time_to_nsec - return number of nanoseconds
+ * @t: a time
+ *
+ * It's sometimes more convenient to deal with time values as
+ * nanoseconds.  Note that this will fit into a 32-bit variable if
+ * it's a time difference of less than ~4 seconds.
+ *
+ * Example:
+ *	...
+ *	printf("Forking time is %u nsec\n",
+ *	       (unsigned)time_to_nsec(forking_time()));
+ *
+ */
+uint64_t time_to_nsec(struct timespec t);
+
+/**
+ * time_from_msec - convert milliseconds to a timespec
  * @msec: time in milliseconds
  *
  * Example:
  *	// 1/2 second timeout
  *	#define TIMEOUT time_from_msec(500)
  */
-struct timeval time_from_msec(uint64_t msec);
+struct timespec time_from_msec(uint64_t msec);
 
 /**
- * time_from_usec - convert microseconds to a timeval
+ * time_from_usec - convert microseconds to a timespec
  * @usec: time in microseconds
  *
  * Example:
  *	// 1/2 second timeout
  *	#define TIMEOUT time_from_usec(500000)
  */
-struct timeval time_from_usec(uint64_t usec);
+struct timespec time_from_usec(uint64_t usec);
+
+/**
+ * time_from_nsec - convert nanoseconds to a timespec
+ * @nsec: time in nanoseconds
+ *
+ * Example:
+ *	// 1/2 second timeout
+ *	#define TIMEOUT time_from_nsec(500000000)
+ */
+struct timespec time_from_nsec(uint64_t nsec);
 
+/**
+ * timespec_to_timeval - convert a timespec to a timeval.
+ * @ts: a timespec.
+ *
+ * Example:
+ *	struct timeval tv;
+ *
+ *	tv = timespec_to_timeval(time_now());
+ */
+static inline struct timeval timespec_to_timeval(struct timespec ts)
+{
+	struct timeval tv;
+	tv.tv_sec = ts.tv_sec;
+	tv.tv_usec = ts.tv_nsec / 1000;
+	return tv;
+}
+
+/**
+ * timeval_to_timespec - convert a timeval to a timespec.
+ * @tv: a timeval.
+ *
+ * Example:
+ *	struct timeval tv = { 0, 500 };
+ *	struct timespec ts;
+ *
+ *	ts = timeval_to_timespec(tv);
+ */
+static inline struct timespec timeval_to_timespec(struct timeval tv)
+{
+	struct timespec ts;
+	ts.tv_sec = tv.tv_sec;
+	ts.tv_nsec = tv.tv_usec * 1000;
+	return ts;
+}
 #endif /* CCAN_TIME_H */