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39 #include <sys/queue.h>
41 #include <rte_atomic.h>
42 #include <rte_common.h>
43 #include <rte_cycles.h>
44 #include <rte_per_lcore.h>
45 #include <rte_memory.h>
46 #include <rte_memzone.h>
47 #include <rte_launch.h>
49 #include <rte_per_lcore.h>
50 #include <rte_lcore.h>
51 #include <rte_branch_prediction.h>
52 #include <rte_spinlock.h>
53 #include <rte_random.h>
54 #include <rte_pause.h>
56 #include "rte_timer.h"
58 LIST_HEAD(rte_timer_list, rte_timer);
61 struct rte_timer pending_head; /**< dummy timer instance to head up list */
62 rte_spinlock_t list_lock; /**< lock to protect list access */
64 /** per-core variable that true if a timer was updated on this
65 * core since last reset of the variable */
68 /** track the current depth of the skiplist */
69 unsigned curr_skiplist_depth;
71 unsigned prev_lcore; /**< used for lcore round robin */
73 /** running timer on this lcore now */
74 struct rte_timer *running_tim;
76 #ifdef RTE_LIBRTE_TIMER_DEBUG
77 /** per-lcore statistics */
78 struct rte_timer_debug_stats stats;
80 } __rte_cache_aligned;
82 /** per-lcore private info for timers */
83 static struct priv_timer priv_timer[RTE_MAX_LCORE];
85 /* when debug is enabled, store some statistics */
86 #ifdef RTE_LIBRTE_TIMER_DEBUG
87 #define __TIMER_STAT_ADD(name, n) do { \
88 unsigned __lcore_id = rte_lcore_id(); \
89 if (__lcore_id < RTE_MAX_LCORE) \
90 priv_timer[__lcore_id].stats.name += (n); \
93 #define __TIMER_STAT_ADD(name, n) do {} while(0)
96 /* Init the timer library. */
98 rte_timer_subsystem_init(void)
102 /* since priv_timer is static, it's zeroed by default, so only init some
105 for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id ++) {
106 rte_spinlock_init(&priv_timer[lcore_id].list_lock);
107 priv_timer[lcore_id].prev_lcore = lcore_id;
111 /* Initialize the timer handle tim for use */
113 rte_timer_init(struct rte_timer *tim)
115 union rte_timer_status status;
117 status.state = RTE_TIMER_STOP;
118 status.owner = RTE_TIMER_NO_OWNER;
119 tim->status.u32 = status.u32;
123 * if timer is pending or stopped (or running on the same core than
124 * us), mark timer as configuring, and on success return the previous
125 * status of the timer
128 timer_set_config_state(struct rte_timer *tim,
129 union rte_timer_status *ret_prev_status)
131 union rte_timer_status prev_status, status;
135 lcore_id = rte_lcore_id();
137 /* wait that the timer is in correct status before update,
138 * and mark it as being configured */
139 while (success == 0) {
140 prev_status.u32 = tim->status.u32;
142 /* timer is running on another core
143 * or ready to run on local core, exit
145 if (prev_status.state == RTE_TIMER_RUNNING &&
146 (prev_status.owner != (uint16_t)lcore_id ||
147 tim != priv_timer[lcore_id].running_tim))
150 /* timer is being configured on another core */
151 if (prev_status.state == RTE_TIMER_CONFIG)
154 /* here, we know that timer is stopped or pending,
155 * mark it atomically as being configured */
156 status.state = RTE_TIMER_CONFIG;
157 status.owner = (int16_t)lcore_id;
158 success = rte_atomic32_cmpset(&tim->status.u32,
163 ret_prev_status->u32 = prev_status.u32;
168 * if timer is pending, mark timer as running
171 timer_set_running_state(struct rte_timer *tim)
173 union rte_timer_status prev_status, status;
174 unsigned lcore_id = rte_lcore_id();
177 /* wait that the timer is in correct status before update,
178 * and mark it as running */
179 while (success == 0) {
180 prev_status.u32 = tim->status.u32;
182 /* timer is not pending anymore */
183 if (prev_status.state != RTE_TIMER_PENDING)
186 /* here, we know that timer is stopped or pending,
187 * mark it atomically as being configured */
188 status.state = RTE_TIMER_RUNNING;
189 status.owner = (int16_t)lcore_id;
190 success = rte_atomic32_cmpset(&tim->status.u32,
199 * Return a skiplist level for a new entry.
200 * This probabalistically gives a level with p=1/4 that an entry at level n
201 * will also appear at level n+1.
204 timer_get_skiplist_level(unsigned curr_depth)
206 #ifdef RTE_LIBRTE_TIMER_DEBUG
207 static uint32_t i, count = 0;
208 static uint32_t levels[MAX_SKIPLIST_DEPTH] = {0};
211 /* probability value is 1/4, i.e. all at level 0, 1 in 4 is at level 1,
212 * 1 in 16 at level 2, 1 in 64 at level 3, etc. Calculated using lowest
213 * bit position of a (pseudo)random number.
215 uint32_t rand = rte_rand() & (UINT32_MAX - 1);
216 uint32_t level = rand == 0 ? MAX_SKIPLIST_DEPTH : (rte_bsf32(rand)-1) / 2;
218 /* limit the levels used to one above our current level, so we don't,
219 * for instance, have a level 0 and a level 7 without anything between
221 if (level > curr_depth)
223 if (level >= MAX_SKIPLIST_DEPTH)
224 level = MAX_SKIPLIST_DEPTH-1;
225 #ifdef RTE_LIBRTE_TIMER_DEBUG
228 if (count % 10000 == 0)
229 for (i = 0; i < MAX_SKIPLIST_DEPTH; i++)
230 printf("Level %u: %u\n", (unsigned)i, (unsigned)levels[i]);
236 * For a given time value, get the entries at each level which
237 * are <= that time value.
240 timer_get_prev_entries(uint64_t time_val, unsigned tim_lcore,
241 struct rte_timer **prev)
243 unsigned lvl = priv_timer[tim_lcore].curr_skiplist_depth;
244 prev[lvl] = &priv_timer[tim_lcore].pending_head;
247 prev[lvl] = prev[lvl+1];
248 while (prev[lvl]->sl_next[lvl] &&
249 prev[lvl]->sl_next[lvl]->expire <= time_val)
250 prev[lvl] = prev[lvl]->sl_next[lvl];
255 * Given a timer node in the skiplist, find the previous entries for it at
256 * all skiplist levels.
259 timer_get_prev_entries_for_node(struct rte_timer *tim, unsigned tim_lcore,
260 struct rte_timer **prev)
263 /* to get a specific entry in the list, look for just lower than the time
264 * values, and then increment on each level individually if necessary
266 timer_get_prev_entries(tim->expire - 1, tim_lcore, prev);
267 for (i = priv_timer[tim_lcore].curr_skiplist_depth - 1; i >= 0; i--) {
268 while (prev[i]->sl_next[i] != NULL &&
269 prev[i]->sl_next[i] != tim &&
270 prev[i]->sl_next[i]->expire <= tim->expire)
271 prev[i] = prev[i]->sl_next[i];
276 * add in list, lock if needed
277 * timer must be in config state
278 * timer must not be in a list
281 timer_add(struct rte_timer *tim, unsigned tim_lcore, int local_is_locked)
283 unsigned lcore_id = rte_lcore_id();
285 struct rte_timer *prev[MAX_SKIPLIST_DEPTH+1];
287 /* if timer needs to be scheduled on another core, we need to
288 * lock the list; if it is on local core, we need to lock if
289 * we are not called from rte_timer_manage() */
290 if (tim_lcore != lcore_id || !local_is_locked)
291 rte_spinlock_lock(&priv_timer[tim_lcore].list_lock);
293 /* find where exactly this element goes in the list of elements
295 timer_get_prev_entries(tim->expire, tim_lcore, prev);
297 /* now assign it a new level and add at that level */
298 const unsigned tim_level = timer_get_skiplist_level(
299 priv_timer[tim_lcore].curr_skiplist_depth);
300 if (tim_level == priv_timer[tim_lcore].curr_skiplist_depth)
301 priv_timer[tim_lcore].curr_skiplist_depth++;
305 tim->sl_next[lvl] = prev[lvl]->sl_next[lvl];
306 prev[lvl]->sl_next[lvl] = tim;
309 tim->sl_next[0] = prev[0]->sl_next[0];
310 prev[0]->sl_next[0] = tim;
312 /* save the lowest list entry into the expire field of the dummy hdr
313 * NOTE: this is not atomic on 32-bit*/
314 priv_timer[tim_lcore].pending_head.expire = priv_timer[tim_lcore].\
315 pending_head.sl_next[0]->expire;
317 if (tim_lcore != lcore_id || !local_is_locked)
318 rte_spinlock_unlock(&priv_timer[tim_lcore].list_lock);
322 * del from list, lock if needed
323 * timer must be in config state
324 * timer must be in a list
327 timer_del(struct rte_timer *tim, union rte_timer_status prev_status,
330 unsigned lcore_id = rte_lcore_id();
331 unsigned prev_owner = prev_status.owner;
333 struct rte_timer *prev[MAX_SKIPLIST_DEPTH+1];
335 /* if timer needs is pending another core, we need to lock the
336 * list; if it is on local core, we need to lock if we are not
337 * called from rte_timer_manage() */
338 if (prev_owner != lcore_id || !local_is_locked)
339 rte_spinlock_lock(&priv_timer[prev_owner].list_lock);
341 /* save the lowest list entry into the expire field of the dummy hdr.
342 * NOTE: this is not atomic on 32-bit */
343 if (tim == priv_timer[prev_owner].pending_head.sl_next[0])
344 priv_timer[prev_owner].pending_head.expire =
345 ((tim->sl_next[0] == NULL) ? 0 : tim->sl_next[0]->expire);
347 /* adjust pointers from previous entries to point past this */
348 timer_get_prev_entries_for_node(tim, prev_owner, prev);
349 for (i = priv_timer[prev_owner].curr_skiplist_depth - 1; i >= 0; i--) {
350 if (prev[i]->sl_next[i] == tim)
351 prev[i]->sl_next[i] = tim->sl_next[i];
354 /* in case we deleted last entry at a level, adjust down max level */
355 for (i = priv_timer[prev_owner].curr_skiplist_depth - 1; i >= 0; i--)
356 if (priv_timer[prev_owner].pending_head.sl_next[i] == NULL)
357 priv_timer[prev_owner].curr_skiplist_depth --;
361 if (prev_owner != lcore_id || !local_is_locked)
362 rte_spinlock_unlock(&priv_timer[prev_owner].list_lock);
365 /* Reset and start the timer associated with the timer handle (private func) */
367 __rte_timer_reset(struct rte_timer *tim, uint64_t expire,
368 uint64_t period, unsigned tim_lcore,
369 rte_timer_cb_t fct, void *arg,
372 union rte_timer_status prev_status, status;
374 unsigned lcore_id = rte_lcore_id();
376 /* round robin for tim_lcore */
377 if (tim_lcore == (unsigned)LCORE_ID_ANY) {
378 if (lcore_id < RTE_MAX_LCORE) {
379 /* EAL thread with valid lcore_id */
380 tim_lcore = rte_get_next_lcore(
381 priv_timer[lcore_id].prev_lcore,
383 priv_timer[lcore_id].prev_lcore = tim_lcore;
385 /* non-EAL thread do not run rte_timer_manage(),
386 * so schedule the timer on the first enabled lcore. */
387 tim_lcore = rte_get_next_lcore(LCORE_ID_ANY, 0, 1);
390 /* wait that the timer is in correct status before update,
391 * and mark it as being configured */
392 ret = timer_set_config_state(tim, &prev_status);
396 __TIMER_STAT_ADD(reset, 1);
397 if (prev_status.state == RTE_TIMER_RUNNING &&
398 lcore_id < RTE_MAX_LCORE) {
399 priv_timer[lcore_id].updated = 1;
402 /* remove it from list */
403 if (prev_status.state == RTE_TIMER_PENDING) {
404 timer_del(tim, prev_status, local_is_locked);
405 __TIMER_STAT_ADD(pending, -1);
408 tim->period = period;
409 tim->expire = expire;
413 __TIMER_STAT_ADD(pending, 1);
414 timer_add(tim, tim_lcore, local_is_locked);
416 /* update state: as we are in CONFIG state, only us can modify
417 * the state so we don't need to use cmpset() here */
419 status.state = RTE_TIMER_PENDING;
420 status.owner = (int16_t)tim_lcore;
421 tim->status.u32 = status.u32;
426 /* Reset and start the timer associated with the timer handle tim */
428 rte_timer_reset(struct rte_timer *tim, uint64_t ticks,
429 enum rte_timer_type type, unsigned tim_lcore,
430 rte_timer_cb_t fct, void *arg)
432 uint64_t cur_time = rte_get_timer_cycles();
435 if (unlikely((tim_lcore != (unsigned)LCORE_ID_ANY) &&
436 !rte_lcore_is_enabled(tim_lcore)))
439 if (type == PERIODICAL)
444 return __rte_timer_reset(tim, cur_time + ticks, period, tim_lcore,
448 /* loop until rte_timer_reset() succeed */
450 rte_timer_reset_sync(struct rte_timer *tim, uint64_t ticks,
451 enum rte_timer_type type, unsigned tim_lcore,
452 rte_timer_cb_t fct, void *arg)
454 while (rte_timer_reset(tim, ticks, type, tim_lcore,
459 /* Stop the timer associated with the timer handle tim */
461 rte_timer_stop(struct rte_timer *tim)
463 union rte_timer_status prev_status, status;
464 unsigned lcore_id = rte_lcore_id();
467 /* wait that the timer is in correct status before update,
468 * and mark it as being configured */
469 ret = timer_set_config_state(tim, &prev_status);
473 __TIMER_STAT_ADD(stop, 1);
474 if (prev_status.state == RTE_TIMER_RUNNING &&
475 lcore_id < RTE_MAX_LCORE) {
476 priv_timer[lcore_id].updated = 1;
479 /* remove it from list */
480 if (prev_status.state == RTE_TIMER_PENDING) {
481 timer_del(tim, prev_status, 0);
482 __TIMER_STAT_ADD(pending, -1);
485 /* mark timer as stopped */
487 status.state = RTE_TIMER_STOP;
488 status.owner = RTE_TIMER_NO_OWNER;
489 tim->status.u32 = status.u32;
494 /* loop until rte_timer_stop() succeed */
496 rte_timer_stop_sync(struct rte_timer *tim)
498 while (rte_timer_stop(tim) != 0)
502 /* Test the PENDING status of the timer handle tim */
504 rte_timer_pending(struct rte_timer *tim)
506 return tim->status.state == RTE_TIMER_PENDING;
509 /* must be called periodically, run all timer that expired */
510 void rte_timer_manage(void)
512 union rte_timer_status status;
513 struct rte_timer *tim, *next_tim;
514 struct rte_timer *run_first_tim, **pprev;
515 unsigned lcore_id = rte_lcore_id();
516 struct rte_timer *prev[MAX_SKIPLIST_DEPTH + 1];
520 /* timer manager only runs on EAL thread with valid lcore_id */
521 assert(lcore_id < RTE_MAX_LCORE);
523 __TIMER_STAT_ADD(manage, 1);
524 /* optimize for the case where per-cpu list is empty */
525 if (priv_timer[lcore_id].pending_head.sl_next[0] == NULL)
527 cur_time = rte_get_timer_cycles();
529 #ifdef RTE_ARCH_X86_64
530 /* on 64-bit the value cached in the pending_head.expired will be
531 * updated atomically, so we can consult that for a quick check here
532 * outside the lock */
533 if (likely(priv_timer[lcore_id].pending_head.expire > cur_time))
537 /* browse ordered list, add expired timers in 'expired' list */
538 rte_spinlock_lock(&priv_timer[lcore_id].list_lock);
540 /* if nothing to do just unlock and return */
541 if (priv_timer[lcore_id].pending_head.sl_next[0] == NULL ||
542 priv_timer[lcore_id].pending_head.sl_next[0]->expire > cur_time) {
543 rte_spinlock_unlock(&priv_timer[lcore_id].list_lock);
547 /* save start of list of expired timers */
548 tim = priv_timer[lcore_id].pending_head.sl_next[0];
550 /* break the existing list at current time point */
551 timer_get_prev_entries(cur_time, lcore_id, prev);
552 for (i = priv_timer[lcore_id].curr_skiplist_depth -1; i >= 0; i--) {
553 if (prev[i] == &priv_timer[lcore_id].pending_head)
555 priv_timer[lcore_id].pending_head.sl_next[i] =
557 if (prev[i]->sl_next[i] == NULL)
558 priv_timer[lcore_id].curr_skiplist_depth--;
559 prev[i] ->sl_next[i] = NULL;
562 /* transition run-list from PENDING to RUNNING */
564 pprev = &run_first_tim;
566 for ( ; tim != NULL; tim = next_tim) {
567 next_tim = tim->sl_next[0];
569 ret = timer_set_running_state(tim);
570 if (likely(ret == 0)) {
571 pprev = &tim->sl_next[0];
573 /* another core is trying to re-config this one,
574 * remove it from local expired list
580 /* update the next to expire timer value */
581 priv_timer[lcore_id].pending_head.expire =
582 (priv_timer[lcore_id].pending_head.sl_next[0] == NULL) ? 0 :
583 priv_timer[lcore_id].pending_head.sl_next[0]->expire;
585 rte_spinlock_unlock(&priv_timer[lcore_id].list_lock);
587 /* now scan expired list and call callbacks */
588 for (tim = run_first_tim; tim != NULL; tim = next_tim) {
589 next_tim = tim->sl_next[0];
590 priv_timer[lcore_id].updated = 0;
591 priv_timer[lcore_id].running_tim = tim;
593 /* execute callback function with list unlocked */
594 tim->f(tim, tim->arg);
596 __TIMER_STAT_ADD(pending, -1);
597 /* the timer was stopped or reloaded by the callback
598 * function, we have nothing to do here */
599 if (priv_timer[lcore_id].updated == 1)
602 if (tim->period == 0) {
603 /* remove from done list and mark timer as stopped */
604 status.state = RTE_TIMER_STOP;
605 status.owner = RTE_TIMER_NO_OWNER;
607 tim->status.u32 = status.u32;
610 /* keep it in list and mark timer as pending */
611 rte_spinlock_lock(&priv_timer[lcore_id].list_lock);
612 status.state = RTE_TIMER_PENDING;
613 __TIMER_STAT_ADD(pending, 1);
614 status.owner = (int16_t)lcore_id;
616 tim->status.u32 = status.u32;
617 __rte_timer_reset(tim, tim->expire + tim->period,
618 tim->period, lcore_id, tim->f, tim->arg, 1);
619 rte_spinlock_unlock(&priv_timer[lcore_id].list_lock);
622 priv_timer[lcore_id].running_tim = NULL;
625 /* dump statistics about timers */
626 void rte_timer_dump_stats(FILE *f)
628 #ifdef RTE_LIBRTE_TIMER_DEBUG
629 struct rte_timer_debug_stats sum;
632 memset(&sum, 0, sizeof(sum));
633 for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
634 sum.reset += priv_timer[lcore_id].stats.reset;
635 sum.stop += priv_timer[lcore_id].stats.stop;
636 sum.manage += priv_timer[lcore_id].stats.manage;
637 sum.pending += priv_timer[lcore_id].stats.pending;
639 fprintf(f, "Timer statistics:\n");
640 fprintf(f, " reset = %"PRIu64"\n", sum.reset);
641 fprintf(f, " stop = %"PRIu64"\n", sum.stop);
642 fprintf(f, " manage = %"PRIu64"\n", sum.manage);
643 fprintf(f, " pending = %"PRIu64"\n", sum.pending);
645 fprintf(f, "No timer statistics, RTE_LIBRTE_TIMER_DEBUG is disabled\n");