1 /* LGPL (v2.1 or any later version) - see LICENSE file for details */
2 #include <ccan/timer/timer.h>
3 #include <ccan/array_size/array_size.h>
4 #include <ccan/ilog/ilog.h>
5 #include <ccan/likely/likely.h>
9 #define PER_LEVEL (1ULL << TIMER_LEVEL_BITS)
12 struct list_head list[PER_LEVEL];
15 static uint64_t time_to_grains(struct timeabs t)
17 return t.ts.tv_sec * ((uint64_t)1000000000 / TIMER_GRANULARITY)
18 + (t.ts.tv_nsec / TIMER_GRANULARITY);
21 static struct timeabs grains_to_time(uint64_t grains)
25 t.ts.tv_sec = grains / (1000000000 / TIMER_GRANULARITY);
26 t.ts.tv_nsec = (grains % (1000000000 / TIMER_GRANULARITY))
31 void timers_init(struct timers *timers, struct timeabs start)
35 list_head_init(&timers->far);
36 timers->base = time_to_grains(start);
37 timers->first = -1ULL;
38 for (i = 0; i < ARRAY_SIZE(timers->level); i++)
39 timers->level[i] = NULL;
42 static unsigned int level_of(const struct timers *timers, uint64_t time)
46 /* Level depends how far away it is. */
47 diff = time - timers->base;
48 return ilog64(diff / 2) / TIMER_LEVEL_BITS;
51 static void timer_add_raw(struct timers *timers, struct timer *t)
54 unsigned int level = level_of(timers, t->time);
56 if (!timers->level[level])
59 int off = (t->time >> (level*TIMER_LEVEL_BITS)) & (PER_LEVEL-1);
60 l = &timers->level[level]->list[off];
63 list_add_tail(l, &t->list);
66 void timer_init(struct timer *t)
68 list_node_init(&t->list);
71 static bool list_node_initted(const struct list_node *n)
76 void timer_add(struct timers *timers, struct timer *t, struct timeabs when)
78 assert(list_node_initted(&t->list));
80 t->time = time_to_grains(when);
82 /* Added in the past? Treat it as imminent. */
83 if (t->time < timers->base)
84 t->time = timers->base;
85 if (t->time < timers->first)
86 timers->first = t->time;
88 timer_add_raw(timers, t);
92 void timer_del(struct timers *timers, struct timer *t)
94 list_del_init(&t->list);
97 static void timers_far_get(struct timers *timers,
98 struct list_head *list,
101 struct timer *i, *next;
103 list_for_each_safe(&timers->far, i, next, list) {
104 if (i->time <= when) {
105 list_del_from(&timers->far, &i->list);
106 list_add_tail(list, &i->list);
111 static void add_level(struct timers *timers, unsigned int level)
113 struct timer_level *l;
116 struct list_head from_far;
118 l = malloc(sizeof(*l));
122 for (i = 0; i < ARRAY_SIZE(l->list); i++)
123 list_head_init(&l->list[i]);
124 timers->level[level] = l;
126 list_head_init(&from_far);
127 timers_far_get(timers, &from_far,
128 timers->base + (1ULL << ((level+1)*TIMER_LEVEL_BITS)) - 1);
130 while ((t = list_pop(&from_far, struct timer, list)) != NULL)
131 timer_add_raw(timers, t);
134 /* We don't need to search past the first at level 0, since the
135 * bucket range is 1; they're all the same. */
136 static const struct timer *find_first(const struct list_head *list,
138 const struct timer *prev)
142 list_for_each(list, t, list) {
143 if (!prev || t->time < prev->time)
151 /* FIXME: Suboptimal */
152 static const struct timer *brute_force_first(const struct timers *timers)
155 const struct timer *found = NULL;
157 for (l = 0; l < ARRAY_SIZE(timers->level) && timers->level[l]; l++) {
158 for (i = 0; i < PER_LEVEL; i++)
159 found = find_first(&timers->level[l]->list[i], l,
163 found = find_first(&timers->far, -1U, found);
167 static const struct timer *get_first(const struct timers *timers)
171 /* Where can we start from? */
172 if (timers->first < timers->base)
175 time = timers->first;
177 /* We can have just far timers, for example. */
178 if (timers->level[0]) {
179 /* First search rest of lower buckets; we've already spilled
180 * so if we find one there we don't need to search further. */
181 unsigned int i, off = time % PER_LEVEL;
183 for (i = off; i < PER_LEVEL; i++) {
184 struct list_head *h = &timers->level[0]->list[i];
186 return find_first(h, 0, NULL);
190 /* From here on, we're searching non-normalized parts of the
191 * data structure, which is much subtler.
193 * So we brute force. */
194 return brute_force_first(timers);
197 static bool update_first(struct timers *timers)
199 const struct timer *found = get_first(timers);
202 timers->first = -1ULL;
206 timers->first = found->time;
210 bool timer_earliest(struct timers *timers, struct timeabs *first)
212 if (!update_first(timers))
215 *first = grains_to_time(timers->first);
219 /* Assume no timers before 'time', cascade down and update base time. */
220 static void timer_fast_forward(struct timers *timers, uint64_t time)
222 unsigned int level, changed;
224 struct list_head list;
227 /* How many bits changed between base and time?
228 * Each time we wrap, we need to empty buckets from above. */
229 if (time == timers->base)
232 changed = ilog64_nz(time ^ timers->base);
233 level = (changed - 1) / TIMER_LEVEL_BITS;
235 /* Buckets always empty downwards, so we could cascade manually,
236 * but it's rarely very many so we just remove and re-add */
237 list_head_init(&list);
240 if (!timers->level[level]) {
241 /* We need any which belong on this level. */
242 timers_far_get(timers, &list,
244 + (1ULL << ((level+1)*TIMER_LEVEL_BITS))-1);
249 /* Get all timers from this bucket. */
250 src = (time >> (level * TIMER_LEVEL_BITS)) % PER_LEVEL;
251 list_append_list(&list,
252 &timers->level[level]->list[src]);
256 /* Did we hit the last level? If so, add. */
257 if (need_level != -1)
258 add_level(timers, need_level);
260 /* Fast-forward the time, and re-add everyone. */
262 while ((i = list_pop(&list, struct timer, list)) != NULL)
263 timer_add_raw(timers, i);
266 /* Returns an expired timer. */
267 struct timer *timers_expire(struct timers *timers, struct timeabs expire)
269 uint64_t now = time_to_grains(expire);
273 assert(now >= timers->base);
275 if (!timers->level[0]) {
276 if (list_empty(&timers->far))
278 add_level(timers, 0);
282 if (timers->first > now) {
283 timer_fast_forward(timers, now);
287 timer_fast_forward(timers, timers->first);
288 off = timers->base % PER_LEVEL;
290 /* This *may* be NULL, if we deleted the first timer */
291 t = list_pop(&timers->level[0]->list[off], struct timer, list);
293 list_node_init(&t->list);
294 } while (!t && update_first(timers));
299 static bool timer_list_check(const struct list_head *l,
300 uint64_t min, uint64_t max, uint64_t first,
301 const char *abortstr)
303 const struct timer *t;
305 if (!list_check(l, abortstr))
308 list_for_each(l, t, list) {
309 if (t->time < min || t->time > max) {
312 "%s: timer %p %llu not %llu-%llu\n",
313 abortstr, t, (long long)t->time,
314 (long long)min, (long long)max);
319 if (t->time < first) {
322 "%s: timer %p %llu < minimum %llu\n",
323 abortstr, t, (long long)t->time,
333 struct timers *timers_check(const struct timers *timers, const char *abortstr)
335 unsigned int l, i, off;
339 if (!timers->level[0])
342 /* First level is simple. */
343 off = timers->base % PER_LEVEL;
344 for (i = 0; i < PER_LEVEL; i++) {
347 h = &timers->level[l]->list[(i+off) % PER_LEVEL];
348 if (!timer_list_check(h, timers->base + i, timers->base + i,
349 timers->first, abortstr))
353 /* For other levels, "current" bucket has been emptied, and may contain
354 * entries for the current + level_size bucket. */
355 for (l = 1; l < ARRAY_SIZE(timers->level) && timers->level[l]; l++) {
356 uint64_t per_bucket = 1ULL << (TIMER_LEVEL_BITS * l);
358 off = ((timers->base >> (l*TIMER_LEVEL_BITS)) % PER_LEVEL);
359 /* We start at *next* bucket. */
360 base = (timers->base & ~(per_bucket - 1)) + per_bucket;
362 for (i = 1; i <= PER_LEVEL; i++) {
365 h = &timers->level[l]->list[(i+off) % PER_LEVEL];
366 if (!timer_list_check(h, base, base + per_bucket - 1,
367 timers->first, abortstr))
374 base = (timers->base & ~((1ULL << (TIMER_LEVEL_BITS * l)) - 1))
375 + (1ULL << (TIMER_LEVEL_BITS * l)) - 1;
376 if (!timer_list_check(&timers->far, base, -1ULL, timers->first,
380 return (struct timers *)timers;
383 #ifdef CCAN_TIMER_DEBUG
384 static void dump_bucket_stats(FILE *fp, const struct list_head *h)
386 unsigned long long min, max, num;
397 list_for_each(h, t, list) {
404 fprintf(fp, " %llu (%llu-%llu)\n",
408 void timers_dump(const struct timers *timers, FILE *fp)
410 unsigned int l, i, off;
411 unsigned long long base;
416 fprintf(fp, "Base: %llu\n", (unsigned long long)timers->base);
418 if (!timers->level[0])
421 fprintf(fp, "Level 0:\n");
423 /* First level is simple. */
424 off = timers->base % PER_LEVEL;
425 for (i = 0; i < PER_LEVEL; i++) {
426 const struct list_head *h;
428 fprintf(fp, " Bucket %llu (%lu):",
429 (i+off) % PER_LEVEL, timers->base + i);
430 h = &timers->level[0]->list[(i+off) % PER_LEVEL];
431 dump_bucket_stats(fp, h);
434 /* For other levels, "current" bucket has been emptied, and may contain
435 * entries for the current + level_size bucket. */
436 for (l = 1; l < ARRAY_SIZE(timers->level) && timers->level[l]; l++) {
437 uint64_t per_bucket = 1ULL << (TIMER_LEVEL_BITS * l);
439 off = ((timers->base >> (l*TIMER_LEVEL_BITS)) % PER_LEVEL);
440 /* We start at *next* bucket. */
441 base = (timers->base & ~(per_bucket - 1)) + per_bucket;
443 fprintf(fp, "Level %u:\n", l);
444 for (i = 1; i <= PER_LEVEL; i++) {
445 const struct list_head *h;
447 fprintf(fp, " Bucket %llu (%llu - %llu):",
449 base, base + per_bucket - 1);
451 h = &timers->level[l]->list[(i+off) % PER_LEVEL];
452 dump_bucket_stats(fp, h);
458 if (!list_empty(&timers->far)) {
459 fprintf(fp, "Far timers:");
460 dump_bucket_stats(fp, &timers->far);
465 void timers_cleanup(struct timers *timers)
469 for (l = 0; l < ARRAY_SIZE(timers->level); l++)
470 free(timers->level[l]);