X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftimer%2Ftimer.c;h=91f46393958acef5b6e9dc10968f14344b35ab5d;hp=9486e6b92872ac22a50f38fd14f5077b2fd220e3;hb=ad2ce76c10f808283ea7cf25cd8e76a15710c4f3;hpb=606cca7b0ed5236d1df1c4436ca79db6e3fd5321

diff --git a/ccan/timer/timer.c b/ccan/timer/timer.c
index 9486e6b9..91f46393 100644
--- a/ccan/timer/timer.c
+++ b/ccan/timer/timer.c
@@ -12,67 +12,111 @@ struct timer_level {
 	struct list_head list[PER_LEVEL];
 };
 
-static uint64_t time_to_grains(struct timespec ts)
+static uint64_t time_to_grains(struct timemono t)
 {
-	return ts.tv_sec * ((uint64_t)1000000000 / TIMER_GRANULARITY)
-		+ (ts.tv_nsec / TIMER_GRANULARITY);
+	return t.ts.tv_sec * ((uint64_t)1000000000 / TIMER_GRANULARITY)
+		+ (t.ts.tv_nsec / TIMER_GRANULARITY);
 }
 
-static struct timespec grains_to_time(uint64_t grains)
+static struct timemono grains_to_time(uint64_t grains)
 {
-	struct timespec ts;
+	struct timemono t;
 
-	ts.tv_sec = grains / (1000000000 / TIMER_GRANULARITY);
-	ts.tv_nsec = (grains % (1000000000 / TIMER_GRANULARITY))
+	t.ts.tv_sec = grains / (1000000000 / TIMER_GRANULARITY);
+	t.ts.tv_nsec = (grains % (1000000000 / TIMER_GRANULARITY))
 		* TIMER_GRANULARITY;
-	return ts;
+	return t;
 }
 
-void timers_init(struct timers *timers, struct timespec start)
+void timers_init(struct timers *timers, struct timemono start)
 {
 	unsigned int i;
 
 	list_head_init(&timers->far);
 	timers->base = time_to_grains(start);
+	timers->first = -1ULL;
+	memset(timers->firsts, 0xFF, sizeof(timers->firsts));
 	for (i = 0; i < ARRAY_SIZE(timers->level); i++)
 		timers->level[i] = NULL;
 }
 
-static void timer_add_raw(struct timers *timers, struct timer *t)
+static unsigned int level_of(const struct timers *timers, uint64_t time)
 {
-	struct list_head *l;
 	uint64_t diff;
-	unsigned int level;
 
 	/* Level depends how far away it is. */
-	diff = t->time - timers->base;
-	level = ilog64(diff / 2) / TIMER_LEVEL_BITS;
+	diff = time - timers->base;
+	return ilog64(diff / 2) / TIMER_LEVEL_BITS;
+}
+
+static void timer_add_raw(struct timers *timers, struct timer *t)
+{
+	struct list_head *l;
+	unsigned int level = level_of(timers, t->time);
+	uint64_t *first;
 
-	if (!timers->level[level])
+	if (!timers->level[level]) {
 		l = &timers->far;
-	else {
+		first = &timers->firsts[ARRAY_SIZE(timers->level)];
+	} else {
 		int off = (t->time >> (level*TIMER_LEVEL_BITS)) & (PER_LEVEL-1);
 		l = &timers->level[level]->list[off];
+		first = &timers->firsts[level];
 	}
 
 	list_add_tail(l, &t->list);
+	if (t->time < *first)
+		*first = t->time;
+}
+
+void timer_init(struct timer *t)
+{
+	list_node_init(&t->list);
+}
+
+static bool list_node_initted(const struct list_node *n)
+{
+	return n->prev == n;
+}
+
+void timer_addrel(struct timers *timers, struct timer *t, struct timerel rel)
+{
+	assert(list_node_initted(&t->list));
+
+	t->time = time_to_grains(timemono_add(time_mono(), rel));
+
+#if TIME_HAVE_MONOTONIC
+	assert(t->time >= timers->base);
+#else
+	/* Added in the past?  Treat it as imminent. */
+	if (t->time < timers->base)
+		t->time = timers->base;
+#endif
+	if (t->time < timers->first)
+		timers->first = t->time;
+
+	timer_add_raw(timers, t);
 }
 
-void timer_add(struct timers *timers, struct timer *t, struct timespec when)
+void timer_addmono(struct timers *timers, struct timer *t, struct timemono when)
 {
+	assert(list_node_initted(&t->list));
+
 	t->time = time_to_grains(when);
 
 	/* Added in the past?  Treat it as imminent. */
 	if (t->time < timers->base)
 		t->time = timers->base;
+	if (t->time < timers->first)
+		timers->first = t->time;
 
 	timer_add_raw(timers, t);
 }
 
 /* FIXME: inline */
-void timer_del(struct timers *timers, struct timer *t)
+void timer_del(struct timers *timers UNNEEDED, struct timer *t)
 {
-	list_del(&t->list);
+	list_del_init(&t->list);
 }
 
 static void timers_far_get(struct timers *timers,
@@ -112,42 +156,10 @@ static void add_level(struct timers *timers, unsigned int level)
 		timer_add_raw(timers, t);
 }
 
-/* Take timers from level and distribute them down one. */
-static void cascade(struct timers *timers, unsigned int level)
-{
-	struct timer *i;
-	struct list_head from_far, *list;
-
-	if (level == ARRAY_SIZE(timers->level) || !timers->level[level]) {
-		list_head_init(&from_far);
-		timers_far_get(timers, &from_far,
-			       timers->base
-			       + (1ULL << (level*TIMER_LEVEL_BITS))-1);
-		list = &from_far;
-		if (level != ARRAY_SIZE(timers->level))
-			add_level(timers, level);
-	} else {
-		unsigned src;
-
-		src = (timers->base >> (level * TIMER_LEVEL_BITS)) % PER_LEVEL;
-		if (src == 0)
-			cascade(timers, level + 1);
-		list = &timers->level[level]->list[src];
-	}
-
-	while ((i = list_pop(list, struct timer, list)) != NULL) {
-		unsigned dst;
-
-		assert(i->time >= timers->base);
-		assert(i->time < (timers->base
-				  + (1ULL << ((level+1)*TIMER_LEVEL_BITS))));
-
-		dst = (i->time >> ((level-1)*TIMER_LEVEL_BITS)) % PER_LEVEL;
-		list_add_tail(&timers->level[level-1]->list[dst], &i->list);
-	}
-}
-
+/* We don't need to search past the first at level 0, since the
+ * bucket range is 1; they're all the same. */
 static const struct timer *find_first(const struct list_head *list,
+				      unsigned int level,
 				      const struct timer *prev)
 {
 	struct timer *t;
@@ -155,68 +167,105 @@ static const struct timer *find_first(const struct list_head *list,
 	list_for_each(list, t, list) {
 		if (!prev || t->time < prev->time)
 			prev = t;
+		if (level == 0)
+			break;
 	}
 	return prev;
 }
 
-static struct timer *get_first(const struct timers *timers)
+/* Update level's first watermark, and return overall first. */
+static const struct timer *first_for_level(struct timers *timers,
+					   size_t level,
+					   const struct timer *level_first,
+					   const struct timer *first)
+{
+	if (level_first) {
+		timers->firsts[level] = level_first->time;
+		if (!first || level_first->time < first->time)
+			first = level_first;
+	} else {
+		timers->firsts[level] = -1ULL;
+	}
+	return first;
+}
+
+static bool level_may_beat(const struct timers *timers, size_t level,
+			   const struct timer *first)
+{
+	return !first || timers->firsts[level] < first->time;
+}
+
+/* FIXME: Suboptimal */
+static const struct timer *brute_force_first(struct timers *timers)
 {
-	unsigned int level = 0, i, off;
-	bool need_next;
-	uint64_t base = timers->base;
+	unsigned int l, i;
 	const struct timer *found = NULL;
-	struct list_head *h;
 
-next:
-	if (!timers->level[level])
-		return (struct timer *)find_first(&timers->far, NULL);
+	for (l = 0; l < ARRAY_SIZE(timers->level) && timers->level[l]; l++) {
+		const struct timer *t = NULL;
 
-	need_next = false;
-	off = base % PER_LEVEL;
-	for (i = 0; i < PER_LEVEL; i++) {
-		h = &timers->level[level]->list[(i+off) % PER_LEVEL];
+		/* Do we know they don't have a better one? */
+		if (!level_may_beat(timers, l, found))
+			continue;
 
-		if (!list_empty(h))
-			break;
+		/* Find first timer on this level. */
+		for (i = 0; i < PER_LEVEL; i++)
+			t = find_first(&timers->level[l]->list[i], l, t);
 
-		/* We haven't cascaded yet, so if we wrap, we'll need to
-		 * check next level, too. */
-		if (i + off == PER_LEVEL)
-			need_next = true;
+		found = first_for_level(timers, l, t, found);
 	}
-	if (i == PER_LEVEL) {
-		level++;
-		base >>= TIMER_LEVEL_BITS;
-		goto next;
+
+	/* Check (and update) far list if there's a chance. */
+	l = ARRAY_SIZE(timers->level);
+	if (level_may_beat(timers, l, found)) {
+		const struct timer *t = find_first(&timers->far, l, NULL);
+		found = first_for_level(timers, l, t, found);
 	}
 
-	/* Level 0 is exact, so they're all the same. */
-	if (level == 0)
-		found = list_top(h, struct timer, list);
-	else
-		found = find_first(h, NULL);
+	return found;
+}
 
-	if (need_next) {
-		if (!timers->level[level+1]) {
-			found = find_first(&timers->far, found);
-		} else {
-			base >>= TIMER_LEVEL_BITS;
-			off = base % PER_LEVEL;
-			h = &timers->level[level+1]->list[off];
-			found = find_first(h, found);
+static const struct timer *get_first(struct timers *timers)
+{
+	/* We can have just far timers, for example. */
+	if (timers->level[0]) {
+		/* First search rest of lower buckets; we've already spilled
+		 * so if we find one there we don't need to search further. */
+		unsigned int i, off = timers->base % PER_LEVEL;
+
+		for (i = off; i < PER_LEVEL; i++) {
+			struct list_head *h = &timers->level[0]->list[i];
+			if (!list_empty(h))
+				return find_first(h, 0, NULL);
 		}
 	}
 
-	return (struct timer *)found;
+	/* From here on, we're searching non-normalized parts of the
+	 * data structure, which is much subtler.
+	 *
+	 * So we brute force. */
+	return brute_force_first(timers);
 }
 
-bool timer_earliest(const struct timers *timers, struct timespec *first)
+static bool update_first(struct timers *timers)
 {
-	struct timer *found = get_first(timers);
+	const struct timer *found = get_first(timers);
 
-	if (!found)
+	if (!found) {
+		timers->first = -1ULL;
 		return false;
-	*first = grains_to_time(found->time);
+ 	}
+
+	timers->first = found->time;
+	return true;
+}
+
+bool timer_earliest(struct timers *timers, struct timemono *first)
+{
+	if (!update_first(timers))
+		return false;
+
+	*first = grains_to_time(timers->first);
 	return true;
 }
 
@@ -267,43 +316,41 @@ static void timer_fast_forward(struct timers *timers, uint64_t time)
 		timer_add_raw(timers, i);
 }
 
-/* Fills list of expired timers. */
-void timers_expire(struct timers *timers,
-		   struct timespec expire,
-		   struct list_head *list)
+/* Returns an expired timer. */
+struct timer *timers_expire(struct timers *timers, struct timemono expire)
 {
 	uint64_t now = time_to_grains(expire);
 	unsigned int off;
-	const struct timer *first;
+	struct timer *t;
 
 	assert(now >= timers->base);
 
-	list_head_init(list);
-
 	if (!timers->level[0]) {
 		if (list_empty(&timers->far))
-			return;
+			return NULL;
 		add_level(timers, 0);
 	}
 
-	while ((first = get_first(timers)) != NULL) {
-		assert(first->time >= timers->base);
-		if (first->time > now) {
+	do {
+		if (timers->first > now) {
 			timer_fast_forward(timers, now);
-			break;
+			return NULL;
 		}
 
-		timer_fast_forward(timers, first->time);
+		timer_fast_forward(timers, timers->first);
 		off = timers->base % PER_LEVEL;
 
-		list_append_list(list, &timers->level[0]->list[off]);
-		if (timers->base == now)
-			break;
-	}
+		/* This *may* be NULL, if we deleted the first timer */
+		t = list_pop(&timers->level[0]->list[off], struct timer, list);
+		if (t)
+			list_node_init(&t->list);
+	} while (!t && update_first(timers));
+
+	return t;
 }
 
 static bool timer_list_check(const struct list_head *l,
-			     uint64_t min, uint64_t max,
+			     uint64_t min, uint64_t max, uint64_t first,
 			     const char *abortstr)
 {
 	const struct timer *t;
@@ -316,7 +363,18 @@ static bool timer_list_check(const struct list_head *l,
 			if (abortstr) {
 				fprintf(stderr,
 					"%s: timer %p %llu not %llu-%llu\n",
-					abortstr, t, t->time, min, max);
+					abortstr, t, (long long)t->time,
+					(long long)min, (long long)max);
+				abort();
+			}
+			return false;
+		}
+		if (t->time < first) {
+			if (abortstr) {
+				fprintf(stderr,
+					"%s: timer %p %llu < minimum %llu\n",
+					abortstr, t, (long long)t->time,
+					(long long)first);
 				abort();
 			}
 			return false;
@@ -341,13 +399,13 @@ struct timers *timers_check(const struct timers *timers, const char *abortstr)
 
 		h = &timers->level[l]->list[(i+off) % PER_LEVEL];
 		if (!timer_list_check(h, timers->base + i, timers->base + i,
-				      abortstr))
+				      timers->firsts[l], abortstr))
 			return NULL;
 	}
 
 	/* For other levels, "current" bucket has been emptied, and may contain
 	 * entries for the current + level_size bucket. */
-	for (l = 1; timers->level[l] && l < PER_LEVEL; l++) {
+	for (l = 1; l < ARRAY_SIZE(timers->level) && timers->level[l]; l++) {
 		uint64_t per_bucket = 1ULL << (TIMER_LEVEL_BITS * l);
 
 		off = ((timers->base >> (l*TIMER_LEVEL_BITS)) % PER_LEVEL);
@@ -359,7 +417,7 @@ struct timers *timers_check(const struct timers *timers, const char *abortstr)
 
 			h = &timers->level[l]->list[(i+off) % PER_LEVEL];
 			if (!timer_list_check(h, base, base + per_bucket - 1,
-					      abortstr))
+					      timers->firsts[l], abortstr))
 				return NULL;
 			base += per_bucket;
 		}
@@ -368,59 +426,95 @@ struct timers *timers_check(const struct timers *timers, const char *abortstr)
 past_levels:
 	base = (timers->base & ~((1ULL << (TIMER_LEVEL_BITS * l)) - 1))
 		+ (1ULL << (TIMER_LEVEL_BITS * l)) - 1;
-	if (!timer_list_check(&timers->far, base, -1ULL, abortstr))
+	if (!timer_list_check(&timers->far, base, -1ULL,
+			      timers->firsts[ARRAY_SIZE(timers->level)],
+			      abortstr))
 		return NULL;
 
 	return (struct timers *)timers;
 }
 
-//#ifdef CCAN_TIMER_DEBUG
-void timers_dump(const struct timers *timers, FILE *fp)
+#ifdef CCAN_TIMER_DEBUG
+static void dump_bucket_stats(FILE *fp, const struct list_head *h)
 {
-	unsigned int l, i;
-	uint64_t min, max, num;
+	unsigned long long min, max, num;
 	struct timer *t;
 
-	if (!fp)
-		fp = stderr;
-
-	fprintf(fp, "Base: %llu\n", timers->base);
-
-	for (l = 0; timers->level[l] && l < ARRAY_SIZE(timers->level); l++) {
-		fprintf(fp, "Level %i (+%llu):\n",
-			l, (uint64_t)1 << (TIMER_LEVEL_BITS * l));
-		for (i = 0; i < (1 << TIMER_LEVEL_BITS); i++) {
-
-			if (list_empty(&timers->level[l]->list[i]))
-				continue;
-			min = -1ULL;
-			max = 0;
-			num = 0;
-			list_for_each(&timers->level[l]->list[i], t, list) {
-				if (t->time < min)
-					min = t->time;
-				if (t->time > max)
-					max = t->time;
-				num++;
-			}
-			fprintf(stderr, "  %llu (+%llu-+%llu)\n",
-				num, min - timers->base, max - timers->base);
-		}
+	if (list_empty(h)) {
+		printf("\n");
+		return;
 	}
 
 	min = -1ULL;
 	max = 0;
 	num = 0;
-	list_for_each(&timers->far, t, list) {
+	list_for_each(h, t, list) {
 		if (t->time < min)
 			min = t->time;
 		if (t->time > max)
 			max = t->time;
 		num++;
 	}
-	fprintf(stderr, "Far: %llu (%llu-%llu)\n", num, min, max);
+	fprintf(fp, " %llu (%llu-%llu)\n",
+		num, min, max);
+}
+
+void timers_dump(const struct timers *timers, FILE *fp)
+{
+	unsigned int l, i, off;
+	unsigned long long base;
+
+	if (!fp)
+		fp = stderr;
+
+	fprintf(fp, "Base: %llu\n", (unsigned long long)timers->base);
+
+	if (!timers->level[0])
+		goto past_levels;
+
+	fprintf(fp, "Level 0:\n");
+
+	/* First level is simple. */
+	off = timers->base % PER_LEVEL;
+	for (i = 0; i < PER_LEVEL; i++) {
+		const struct list_head *h;
+
+		fprintf(fp, "  Bucket %llu (%lu):",
+			(i+off) % PER_LEVEL, timers->base + i);
+		h = &timers->level[0]->list[(i+off) % PER_LEVEL];
+		dump_bucket_stats(fp, h);
+	}
+
+	/* For other levels, "current" bucket has been emptied, and may contain
+	 * entries for the current + level_size bucket. */
+	for (l = 1; l < ARRAY_SIZE(timers->level) && timers->level[l]; l++) {
+		uint64_t per_bucket = 1ULL << (TIMER_LEVEL_BITS * l);
+
+		off = ((timers->base >> (l*TIMER_LEVEL_BITS)) % PER_LEVEL);
+		/* We start at *next* bucket. */
+		base = (timers->base & ~(per_bucket - 1)) + per_bucket;
+
+		fprintf(fp, "Level %u:\n", l);
+		for (i = 1; i <= PER_LEVEL; i++) {
+			const struct list_head *h;
+
+			fprintf(fp, "  Bucket %llu (%llu - %llu):",
+				(i+off) % PER_LEVEL,
+				base, base + per_bucket - 1);
+
+			h = &timers->level[l]->list[(i+off) % PER_LEVEL];
+			dump_bucket_stats(fp, h);
+			base += per_bucket;
+		}
+	}
+
+past_levels:
+	if (!list_empty(&timers->far)) {
+		fprintf(fp, "Far timers:");
+		dump_bucket_stats(fp, &timers->far);
+	}
 }
-//#endif
+#endif
 
 void timers_cleanup(struct timers *timers)
 {