2 /* Copyright (c) 2010. The SimGrid Team.
3 * All rights reserved. */
5 /* This program is free software; you can redistribute it and/or modify it
6 * under the terms of the license (GNU LGPL) which comes with this package. */
11 #include "xbt/asserts.h"
12 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_chord,
13 "Messages specific for this msg example");
18 static int nb_bits = 16;
19 static int nb_keys = 0;
20 static int timeout = 50;
21 static int max_simulation_time = 1000;
22 static int periodic_stabilize_delay = 20;
23 static int periodic_fix_fingers_delay = 120;
24 static int periodic_check_predecessor_delay = 120;
29 typedef struct finger {
32 } s_finger_t, *finger_t;
39 char* mailbox; // my usual mailbox name
40 s_finger_t *fingers; // finger table, of size nb_bits (fingers[0] is my successor)
41 int pred_id; // predecessor id
42 char* pred_mailbox; // predecessor's mailbox name
43 int next_finger_to_fix; // index of the next finger to fix in fix_fingers()
44 msg_comm_t comm_receive; // current communication to receive
45 xbt_dynar_t comms; // current communications being sent
46 double last_change_date; // last time I changed a finger or my predecessor
50 * Types of tasks exchanged between nodes.
54 TASK_FIND_SUCCESSOR_ANSWER,
56 TASK_GET_PREDECESSOR_ANSWER,
58 TASK_SUCCESSOR_LEAVING,
59 TASK_PREDECESSOR_LEAVING
63 * Data attached with the tasks sent and received
65 typedef struct task_data {
66 e_task_type_t type; // type of task
67 int request_id; // id paramater (used by some types of tasks)
68 int request_finger; // finger parameter (used by some types of tasks)
69 int answer_id; // answer (used by some types of tasks)
70 char* answer_to; // mailbox to send an answer to (or NULL)
71 const char* issuer_host_name; // used for logging
72 } s_task_data_t, *task_data_t;
77 static void chord_initialize(void);
78 static int normalize(int id);
79 static int is_in_interval(int id, int start, int end);
80 static char* get_mailbox(int host_id);
81 static void task_data_destroy(task_data_t task_data);
82 static void print_finger_table(node_t node);
83 static void set_finger(node_t node, int finger_index, int id);
84 static void set_predecessor(node_t node, int predecessor_id);
87 static int node(int argc, char *argv[]);
88 static void handle_task(node_t node, m_task_t task);
91 static void create(node_t node);
92 static int join(node_t node, int known_id);
93 static void leave(node_t node);
94 static int find_successor(node_t node, int id);
95 static int remote_find_successor(node_t node, int ask_to_id, int id);
96 static int remote_get_predecessor(node_t node, int ask_to_id);
97 static int closest_preceding_node(node_t node, int id);
98 static void stabilize(node_t node);
99 static void notify(node_t node, int predecessor_candidate_id);
100 static void remote_notify(node_t node, int notify_to, int predecessor_candidate_id);
101 static void fix_fingers(node_t node);
102 static void check_predecessor(node_t node);
103 static void quit_notify(node_t node, int to);
106 * \brief Global initialization of the Chord simulation.
108 static void chord_initialize(void)
110 // compute the powers of 2 once for all
111 powers2 = xbt_new(int, nb_bits);
114 for (i = 0; i < nb_bits; i++) {
119 DEBUG1("Sets nb_keys to %d", nb_keys);
123 * \brief Turns an id into an equivalent id in [0, nb_keys).
125 * \return the corresponding normalized id
127 static int normalize(int id)
133 // make sure id < nb_keys
140 * \brief Returns whether a id belongs to the interval [start, end].
142 * The parameters are noramlized to make sure they are between 0 and nb_keys - 1).
143 * 1 belongs to [62, 3]
144 * 1 does not belong to [3, 62]
145 * 63 belongs to [62, 3]
146 * 63 does not belong to [3, 62]
147 * 24 belongs to [21, 29]
148 * 24 does not belong to [29, 21]
150 * \param id id to check
151 * \param start lower bound
152 * \param end upper bound
153 * \return a non-zero value if id in in [start, end]
155 static int is_in_interval(int id, int start, int end)
158 start = normalize(start);
159 end = normalize(end);
161 // make sure end >= start and id >= start
174 * \brief Gets the mailbox name of a host given its chord id.
175 * \param node_id id of a node
176 * \return the name of its mailbox
178 static char* get_mailbox(int node_id)
180 return bprintf("mailbox%d", node_id);
184 * \brief Frees the memory used by some task data.
185 * \param task_data the task data to destroy
187 static void task_data_destroy(task_data_t task_data)
189 xbt_free(task_data->answer_to);
194 * \brief Displays the finger table of a node.
197 static void print_finger_table(node_t node)
199 if (XBT_LOG_ISENABLED(msg_chord, xbt_log_priority_verbose)) {
202 VERB0("My finger table:");
203 VERB0("Start | Succ ");
204 for (i = 0; i < nb_bits; i++) {
205 VERB2(" %3d | %3d ", (node->id + pow) % nb_keys, node->fingers[i].id);
208 VERB1("Predecessor: %d", node->pred_id);
213 * \brief Sets a finger of the current node.
214 * \param node the current node
215 * \param finger_index index of the finger to set (0 to nb_bits - 1)
216 * \param id the id to set for this finger
218 static void set_finger(node_t node, int finger_index, int id)
220 if (id != node->fingers[finger_index].id) {
221 node->fingers[finger_index].id = id;
222 xbt_free(node->fingers[finger_index].mailbox);
223 node->fingers[finger_index].mailbox = get_mailbox(id);
224 node->last_change_date = MSG_get_clock();
225 DEBUG2("My new finger #%d is %d", finger_index, id);
230 * \brief Sets the predecessor of the current node.
231 * \param node the current node
232 * \param id the id to predecessor, or -1 to unset the predecessor
234 static void set_predecessor(node_t node, int predecessor_id)
236 if (predecessor_id != node->pred_id) {
237 node->pred_id = predecessor_id;
238 xbt_free(node->pred_mailbox);
240 if (predecessor_id != -1) {
241 node->pred_mailbox = get_mailbox(predecessor_id);
243 node->last_change_date = MSG_get_clock();
245 DEBUG1("My new predecessor is %d", predecessor_id);
250 * \brief Node Function
253 * - the id of a guy I know in the system (except for the first node)
254 * - the time to sleep before I join (except for the first node)
256 int node(int argc, char *argv[])
258 double init_time = MSG_get_clock();
259 m_task_t task = NULL;
260 m_task_t task_received = NULL;
261 msg_comm_t comm_send = NULL;
264 int join_success = 0;
266 double next_stabilize_date = init_time + 10;
267 double next_fix_fingers_date = init_time + 10;
268 double next_check_predecessor_date = init_time + 10;
270 xbt_assert0(argc == 3 || argc == 5, "Wrong number of arguments for this node");
272 // initialize my node
274 node.id = atoi(argv[1]);
275 node.mailbox = get_mailbox(node.id);
276 node.next_finger_to_fix = 0;
277 node.comms = xbt_dynar_new(sizeof(msg_comm_t), NULL);
278 node.fingers = xbt_new0(s_finger_t, nb_bits);
279 node.last_change_date = MSG_get_clock();
281 for (i = 0; i < nb_bits; i++) {
282 set_finger(&node, i, node.id);
285 if (argc == 3) { // first ring
286 deadline = atof(argv[2]);
291 int known_id = atoi(argv[2]);
292 //double sleep_time = atof(argv[3]);
293 deadline = atof(argv[4]);
296 // sleep before starting
297 DEBUG1("Let's sleep during %f", sleep_time);
298 MSG_process_sleep(sleep_time);
300 DEBUG0("Hey! Let's join the system.");
302 join_success = join(&node, known_id);
306 while (MSG_get_clock() < init_time + deadline
307 // && MSG_get_clock() < node.last_change_date + 1000
308 && MSG_get_clock() < max_simulation_time) {
310 if (node.comm_receive == NULL) {
311 task_received = NULL;
312 node.comm_receive = MSG_task_irecv(&task_received, node.mailbox);
313 // FIXME: do not make MSG_task_irecv() calls from several functions
316 if (!MSG_comm_test(node.comm_receive)) {
318 // no task was received: make some periodic calls
319 if (MSG_get_clock() >= next_stabilize_date) {
321 next_stabilize_date = MSG_get_clock() + periodic_stabilize_delay;
323 else if (MSG_get_clock() >= next_fix_fingers_date) {
325 next_fix_fingers_date = MSG_get_clock() + periodic_fix_fingers_delay;
327 else if (MSG_get_clock() >= next_check_predecessor_date) {
328 check_predecessor(&node);
329 next_check_predecessor_date = MSG_get_clock() + periodic_check_predecessor_delay;
332 // nothing to do: sleep for a while
333 MSG_process_sleep(5);
337 // a transfer has occured
339 MSG_error_t status = MSG_comm_get_status(node.comm_receive);
341 if (status != MSG_OK) {
342 DEBUG0("Failed to receive a task. Nevermind.");
343 node.comm_receive = NULL;
346 // the task was successfully received
347 MSG_comm_destroy(node.comm_receive);
348 node.comm_receive = NULL;
349 handle_task(&node, task_received);
353 // see if some communications are finished
354 while ((index = MSG_comm_testany(node.comms)) != -1) {
355 comm_send = xbt_dynar_get_as(node.comms, index, msg_comm_t);
356 MSG_error_t status = MSG_comm_get_status(comm_send);
357 xbt_dynar_remove_at(node.comms, index, &comm_send);
358 DEBUG3("Communication %p is finished with status %d, dynar size is now %lu",
359 comm_send, status, xbt_dynar_length(node.comms));
360 MSG_comm_destroy(comm_send);
364 // clean unfinished comms sent
366 xbt_dynar_foreach(node.comms, cursor, comm_send) {
367 task = MSG_comm_get_task(comm_send);
368 MSG_task_cancel(task);
369 task_data_destroy(MSG_task_get_data(task));
370 MSG_task_destroy(task);
371 MSG_comm_destroy(comm_send);
372 // FIXME: the task is actually not destroyed because MSG thinks that the other side (whose process is dead) is still using it
379 // stop the simulation
380 xbt_dynar_free(&node.comms);
381 xbt_free(node.mailbox);
382 xbt_free(node.pred_mailbox);
383 for (i = 0; i < nb_bits - 1; i++) {
384 xbt_free(node.fingers[i].mailbox);
386 xbt_free(node.fingers);
391 * \brief This function is called when the current node receives a task.
392 * \param node the current node
393 * \param task the task to handle (don't touch it then:
394 * it will be destroyed, reused or forwarded)
396 static void handle_task(node_t node, m_task_t task) {
398 DEBUG1("Handling task %p", task);
399 msg_comm_t comm = NULL;
400 char* mailbox = NULL;
401 task_data_t task_data = (task_data_t) MSG_task_get_data(task);
402 e_task_type_t type = task_data->type;
406 case TASK_FIND_SUCCESSOR:
407 DEBUG2("Receiving a 'Find Successor' request from %s for id %d",
408 task_data->issuer_host_name, task_data->request_id);
409 // is my successor the successor?
410 if (is_in_interval(task_data->request_id, node->id + 1, node->fingers[0].id)) {
411 task_data->type = TASK_FIND_SUCCESSOR_ANSWER;
412 task_data->answer_id = node->fingers[0].id;
413 DEBUG3("Sending back a 'Find Successor Answer' to %s: the successor of %d is %d",
414 task_data->issuer_host_name,
415 task_data->request_id, task_data->answer_id);
416 comm = MSG_task_isend(task, task_data->answer_to);
417 xbt_dynar_push(node->comms, &comm);
420 // otherwise, forward the request to the closest preceding finger in my table
421 int closest = closest_preceding_node(node, task_data->request_id);
422 DEBUG2("Forwarding the 'Find Successor' request for id %d to my closest preceding finger %d",
423 task_data->request_id, closest);
424 mailbox = get_mailbox(closest);
425 comm = MSG_task_isend(task, mailbox);
426 xbt_dynar_push(node->comms, &comm);
431 case TASK_GET_PREDECESSOR:
432 DEBUG1("Receiving a 'Get Predecessor' request from %s", task_data->issuer_host_name);
433 task_data->type = TASK_GET_PREDECESSOR_ANSWER;
434 task_data->answer_id = node->pred_id;
435 DEBUG3("Sending back a 'Get Predecessor Answer' to %s via mailbox '%s': my predecessor is %d",
436 task_data->issuer_host_name,
437 task_data->answer_to, task_data->answer_id);
438 comm = MSG_task_isend(task, task_data->answer_to);
439 xbt_dynar_push(node->comms, &comm);
443 // someone is telling me that he may be my new predecessor
444 DEBUG1("Receiving a 'Notify' request from %s", task_data->issuer_host_name);
445 notify(node, task_data->request_id);
446 task_data_destroy(task_data);
447 MSG_task_destroy(task);
450 case TASK_PREDECESSOR_LEAVING:
451 // my predecessor is about to quit
452 DEBUG1("Receiving a 'Predecessor Leaving' message from %s", task_data->issuer_host_name);
453 // modify my predecessor
454 set_predecessor(node, task_data->request_id);
455 task_data_destroy(task_data);
456 MSG_task_destroy(task);
458 >> notify my new predecessor
459 >> send a notify_predecessors !!
463 case TASK_SUCCESSOR_LEAVING:
464 // my successor is about to quit
465 DEBUG1("Receiving a 'Successor Leaving' message from %s", task_data->issuer_host_name);
466 // modify my successor FIXME : this should be implicit ?
467 set_finger(node, 0, task_data->request_id);
468 task_data_destroy(task_data);
469 MSG_task_destroy(task);
471 >> notify my new successor
472 >> update my table & predecessors table */
475 case TASK_FIND_SUCCESSOR_ANSWER:
476 case TASK_GET_PREDECESSOR_ANSWER:
477 DEBUG2("Ignoring unexpected task of type %d (%p)", type, task);
483 * \brief Initializes the current node as the first one of the system.
484 * \param node the current node
486 static void create(node_t node)
488 DEBUG0("Create a new Chord ring...");
489 set_predecessor(node, -1); // -1 means that I have no predecessor
490 print_finger_table(node);
494 * \brief Makes the current node join the ring, knowing the id of a node
495 * already in the ring
496 * \param node the current node
497 * \param known_id id of a node already in the ring
498 * \return 1 if the join operation succeeded, 0 otherwise
500 static int join(node_t node, int known_id)
502 INFO2("Joining the ring with id %d, knowing node %d", node->id, known_id);
503 set_predecessor(node, -1); // no predecessor (yet)
505 int successor_id = remote_find_successor(node, known_id, node->id);
506 if (successor_id == -1) {
507 INFO0("Cannot join the ring.");
510 set_finger(node, 0, successor_id);
511 print_finger_table(node);
514 return successor_id != -1;
518 * \brief Makes the current node quit the system
519 * \param node the current node
521 static void leave(node_t node)
523 DEBUG0("Well Guys! I Think it's time for me to quit ;)");
524 quit_notify(node, 1); // notify to my successor ( >>> 1 );
525 quit_notify(node, -1); // notify my predecessor ( >>> -1);
530 * \brief Notifies the successor or the predecessor of the current node
532 * \param node the current node
533 * \param to 1 to notify the successor, -1 to notify the predecessor
534 * FIXME: notify both nodes with only one call
536 static void quit_notify(node_t node, int to)
539 task_data_t req_data = xbt_new0(s_task_data_t, 1);
540 req_data->request_id = node->id;
541 req_data->successor_id = node->fingers[0].id;
542 req_data->pred_id = node->pred_id;
543 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
544 req_data->answer_to = NULL;
545 const char* task_name = NULL;
546 const char* to_mailbox = NULL;
547 if (to == 1) { // notify my successor
548 to_mailbox = node->fingers[0].mailbox;
549 INFO2("Telling my Successor %d about my departure via mailbox %s",
550 node->fingers[0].id, to_mailbox);
551 req_data->type = TASK_PREDECESSOR_LEAVING;
553 else if (to == -1) { // notify my predecessor
555 if (node->pred_id == -1) {
559 to_mailbox = node->pred_mailbox;
560 INFO2("Telling my Predecessor %d about my departure via mailbox %s",
561 node->pred_id, to_mailbox);
562 req_data->type = TASK_SUCCESSOR_LEAVING;
564 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
565 //char* mailbox = get_mailbox(to_mailbox);
566 msg_comm_t comm = MSG_task_isend(task, to_mailbox);
567 xbt_dynar_push(node->comms, &comm);
572 * \brief Makes the current node find the successor node of an id.
573 * \param node the current node
574 * \param id the id to find
575 * \return the id of the successor node, or -1 if the request failed
577 static int find_successor(node_t node, int id)
579 // is my successor the successor?
580 if (is_in_interval(id, node->id + 1, node->fingers[0].id)) {
581 return node->fingers[0].id;
584 // otherwise, ask the closest preceding finger in my table
585 int closest = closest_preceding_node(node, id);
586 return remote_find_successor(node, closest, id);
590 * \brief Asks another node the successor node of an id.
591 * \param node the current node
592 * \param ask_to the node to ask to
593 * \param id the id to find
594 * \return the id of the successor node, or -1 if the request failed
596 static int remote_find_successor(node_t node, int ask_to, int id)
600 char* mailbox = get_mailbox(ask_to);
601 task_data_t req_data = xbt_new0(s_task_data_t, 1);
602 req_data->type = TASK_FIND_SUCCESSOR;
603 req_data->request_id = id;
604 req_data->answer_to = xbt_strdup(node->mailbox);
605 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
607 // send a "Find Successor" request to ask_to_id
608 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
609 DEBUG3("Sending a 'Find Successor' request (task %p) to %d for id %d", task_sent, ask_to, id);
610 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
613 DEBUG3("Failed to send the 'Find Successor' request (task %p) to %d for id %d",
614 task_sent, ask_to, id);
615 MSG_task_destroy(task_sent);
616 task_data_destroy(req_data);
620 // receive the answer
621 DEBUG3("Sent a 'Find Successor' request (task %p) to %d for key %d, waiting for the answer",
622 task_sent, ask_to, id);
625 if (node->comm_receive == NULL) {
626 m_task_t task_received = NULL;
627 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
630 res = MSG_comm_wait(node->comm_receive, timeout);
633 DEBUG2("Failed to receive the answer to my 'Find Successor' request (task %p): %d",
636 //MSG_comm_destroy(node->comm_receive);
639 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
640 DEBUG1("Received a task (%p)", task_received);
641 task_data_t ans_data = MSG_task_get_data(task_received);
643 if (task_received != task_sent) {
644 // this is not the expected answer
645 handle_task(node, task_received);
648 // this is our answer
649 DEBUG4("Received the answer to my 'Find Successor' request for id %d (task %p): the successor of key %d is %d",
650 ans_data->request_id, task_received, id, ans_data->answer_id);
651 successor = ans_data->answer_id;
653 MSG_task_destroy(task_received);
654 task_data_destroy(req_data);
657 node->comm_receive = NULL;
666 * \brief Asks another node its predecessor.
667 * \param node the current node
668 * \param ask_to the node to ask to
669 * \return the id of its predecessor node, or -1 if the request failed
670 * (or if the node does not know its predecessor)
672 static int remote_get_predecessor(node_t node, int ask_to)
674 int predecessor_id = -1;
676 char* mailbox = get_mailbox(ask_to);
677 task_data_t req_data = xbt_new0(s_task_data_t, 1);
678 req_data->type = TASK_GET_PREDECESSOR;
679 req_data->answer_to = xbt_strdup(node->mailbox);
680 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
682 // send a "Get Predecessor" request to ask_to_id
683 DEBUG1("Sending a 'Get Predecessor' request to %d", ask_to);
684 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
685 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
688 DEBUG2("Failed to send the 'Get Predecessor' request (task %p) to %d",
690 MSG_task_destroy(task_sent);
691 task_data_destroy(req_data);
695 // receive the answer
696 DEBUG3("Sent 'Get Predecessor' request (task %p) to %d, waiting for the answer on my mailbox '%s'",
697 task_sent, ask_to, req_data->answer_to);
700 if (node->comm_receive == NULL) { // FIXME simplify this
701 m_task_t task_received = NULL;
702 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
705 res = MSG_comm_wait(node->comm_receive, timeout);
708 DEBUG2("Failed to receive the answer to my 'Get Predecessor' request (task %p): %d",
711 //MSG_comm_destroy(node->comm_receive);
714 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
715 task_data_t ans_data = MSG_task_get_data(task_received);
717 if (task_received != task_sent) {
718 handle_task(node, task_received);
721 DEBUG3("Received the answer to my 'Get Predecessor' request (task %p): the predecessor of node %d is %d",
722 task_received, ask_to, ans_data->answer_id);
723 predecessor_id = ans_data->answer_id;
725 MSG_task_destroy(task_received);
726 task_data_destroy(req_data);
729 node->comm_receive = NULL;
734 return predecessor_id;
738 * \brief Returns the closest preceding finger of an id
739 * with respect to the finger table of the current node.
740 * \param node the current node
741 * \param id the id to find
742 * \return the closest preceding finger of that id
744 int closest_preceding_node(node_t node, int id)
747 for (i = nb_bits - 1; i >= 0; i--) {
748 if (is_in_interval(node->fingers[i].id, node->id + 1, id - 1)) {
749 return node->fingers[i].id;
756 * \brief This function is called periodically. It checks the immediate
757 * successor of the current node.
758 * \param node the current node
760 static void stabilize(node_t node)
762 DEBUG0("Stabilizing node");
764 // get the predecessor of my immediate successor
766 int successor_id = node->fingers[0].id;
767 if (successor_id != node->id) {
768 candidate_id = remote_get_predecessor(node, successor_id);
771 candidate_id = node->pred_id;
774 // this node is a candidate to become my new successor
775 if (candidate_id != -1
776 && is_in_interval(candidate_id, node->id + 1, successor_id - 1)) {
777 set_finger(node, 0, candidate_id);
779 if (successor_id != node->id) {
780 remote_notify(node, successor_id, node->id);
785 * \brief Notifies the current node that its predecessor may have changed.
786 * \param node the current node
787 * \param candidate_id the possible new predecessor
789 static void notify(node_t node, int predecessor_candidate_id) {
791 if (node->pred_id == -1
792 || is_in_interval(predecessor_candidate_id, node->pred_id + 1, node->id - 1)) {
794 set_predecessor(node, predecessor_candidate_id);
795 print_finger_table(node);
798 DEBUG1("I don't have to change my predecessor to %d", predecessor_candidate_id);
803 * \brief Notifies a remote node that its predecessor may have changed.
804 * \param node the current node
805 * \param notify_id id of the node to notify
806 * \param candidate_id the possible new predecessor
808 static void remote_notify(node_t node, int notify_id, int predecessor_candidate_id) {
810 task_data_t req_data = xbt_new0(s_task_data_t, 1);
811 req_data->type = TASK_NOTIFY;
812 req_data->request_id = predecessor_candidate_id;
813 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
814 req_data->answer_to = NULL;
816 // send a "Notify" request to notify_id
817 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
818 DEBUG2("Sending a 'Notify' request (task %p) to %d", task, notify_id);
819 char* mailbox = get_mailbox(notify_id);
820 msg_comm_t comm = MSG_task_isend(task, mailbox);
821 xbt_dynar_push(node->comms, &comm);
826 * \brief This function is called periodically.
827 * It refreshes the finger table of the current node.
828 * \param node the current node
830 static void fix_fingers(node_t node) {
832 DEBUG0("Fixing fingers");
833 int i = node->next_finger_to_fix;
834 int id = find_successor(node, node->id + powers2[i]);
837 if (id != node->fingers[i].id) {
838 set_finger(node, i, id);
839 print_finger_table(node);
841 node->next_finger_to_fix = (i + 1) % nb_bits;
846 * \brief This function is called periodically.
847 * It checks whether the predecessor has failed
848 * \param node the current node
850 static void check_predecessor(node_t node)
852 DEBUG0("Checking whether my predecessor is alive");
857 * \brief Main function.
859 int main(int argc, char *argv[])
862 printf("Usage: %s [-nb_bits=n] [-timeout=t] platform_file deployment_file\n", argv[0]);
863 printf("example: %s ../msg_platform.xml chord.xml\n", argv[0]);
867 MSG_global_init(&argc, argv);
869 char **options = &argv[1];
870 while (!strncmp(options[0], "-", 1)) {
872 int length = strlen("-nb_bits=");
873 if (!strncmp(options[0], "-nb_bits=", length) && strlen(options[0]) > length) {
874 nb_bits = atoi(options[0] + length);
875 DEBUG1("Set nb_bits to %d", nb_bits);
879 length = strlen("-timeout=");
880 if (!strncmp(options[0], "-timeout=", length) && strlen(options[0]) > length) {
881 timeout = atoi(options[0] + length);
882 DEBUG1("Set timeout to %d", timeout);
885 xbt_assert1(0, "Invalid chord option '%s'", options[0]);
891 const char* platform_file = options[0];
892 const char* application_file = options[1];
896 MSG_set_channel_number(0);
897 MSG_create_environment(platform_file);
899 MSG_function_register("node", node);
900 MSG_launch_application(application_file);
902 MSG_error_t res = MSG_main();
903 INFO1("Simulation time: %g", MSG_get_clock());