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 #include "mc/modelchecker.h"
14 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_chord,
15 "Messages specific for this msg example");
19 #define MAILBOX_NAME_SIZE 10
21 static int nb_bits = 24;
22 static int nb_keys = 0;
23 static int timeout = 50;
24 static int max_simulation_time = 1000;
25 static int periodic_stabilize_delay = 20;
26 static int periodic_fix_fingers_delay = 120;
27 static int periodic_check_predecessor_delay = 120;
28 static int periodic_lookup_delay = 10;
33 typedef struct finger {
35 char mailbox[MAILBOX_NAME_SIZE]; // string representation of the id
36 } s_finger_t, *finger_t;
43 char mailbox[MAILBOX_NAME_SIZE]; // my mailbox name (string representation of the id)
44 s_finger_t *fingers; // finger table, of size nb_bits (fingers[0] is my successor)
45 int pred_id; // predecessor id
46 char pred_mailbox[MAILBOX_NAME_SIZE]; // predecessor's mailbox name
47 int next_finger_to_fix; // index of the next finger to fix in fix_fingers()
48 msg_comm_t comm_receive; // current communication to receive
49 double last_change_date; // last time I changed a finger or my predecessor
53 * Types of tasks exchanged between nodes.
57 TASK_FIND_SUCCESSOR_ANSWER,
59 TASK_GET_PREDECESSOR_ANSWER,
61 TASK_SUCCESSOR_LEAVING,
62 TASK_PREDECESSOR_LEAVING
66 * Data attached with the tasks sent and received
68 typedef struct task_data {
69 e_task_type_t type; // type of task
70 int request_id; // id paramater (used by some types of tasks)
71 int request_finger; // finger parameter (used by some types of tasks)
72 int answer_id; // answer (used by some types of tasks)
73 char answer_to[MAILBOX_NAME_SIZE]; // mailbox to send an answer to (if any)
74 const char* issuer_host_name; // used for logging
75 } s_task_data_t, *task_data_t;
80 static void chord_initialize(void);
81 static int normalize(int id);
82 static int is_in_interval(int id, int start, int end);
83 static void get_mailbox(int host_id, char* mailbox);
84 static void task_free(void* task);
85 static void print_finger_table(node_t node);
86 static void set_finger(node_t node, int finger_index, int id);
87 static void set_predecessor(node_t node, int predecessor_id);
90 static int node(int argc, char *argv[]);
91 static void handle_task(node_t node, m_task_t task);
94 static void create(node_t node);
95 static int join(node_t node, int known_id);
96 static void leave(node_t node);
97 static int find_successor(node_t node, int id);
98 static int remote_find_successor(node_t node, int ask_to_id, int id);
99 static int remote_get_predecessor(node_t node, int ask_to_id);
100 static int closest_preceding_node(node_t node, int id);
101 static void stabilize(node_t node);
102 static void notify(node_t node, int predecessor_candidate_id);
103 static void remote_notify(node_t node, int notify_to, int predecessor_candidate_id);
104 static void fix_fingers(node_t node);
105 static void check_predecessor(node_t node);
106 static void random_lookup(node_t);
107 static void quit_notify(node_t node, int to);
110 * \brief Global initialization of the Chord simulation.
112 static void chord_initialize(void)
114 // compute the powers of 2 once for all
115 powers2 = xbt_new(int, nb_bits);
118 for (i = 0; i < nb_bits; i++) {
123 DEBUG1("Sets nb_keys to %d", nb_keys);
127 * \brief Turns an id into an equivalent id in [0, nb_keys).
129 * \return the corresponding normalized id
131 static int normalize(int id)
133 // like id % nb_keys, but works with negatives numbers (and faster)
134 return id & (nb_keys - 1);
138 * \brief Returns whether a id belongs to the interval [start, end].
140 * The parameters are noramlized to make sure they are between 0 and nb_keys - 1).
141 * 1 belongs to [62, 3]
142 * 1 does not belong to [3, 62]
143 * 63 belongs to [62, 3]
144 * 63 does not belong to [3, 62]
145 * 24 belongs to [21, 29]
146 * 24 does not belong to [29, 21]
148 * \param id id to check
149 * \param start lower bound
150 * \param end upper bound
151 * \return a non-zero value if id in in [start, end]
153 static int is_in_interval(int id, int start, int end)
156 start = normalize(start);
157 end = normalize(end);
159 // make sure end >= start and id >= start
172 * \brief Gets the mailbox name of a host given its chord id.
173 * \param node_id id of a node
174 * \param mailbox pointer to where the mailbox name should be written
175 * (there must be enough space)
177 static void get_mailbox(int node_id, char* mailbox)
179 snprintf(mailbox, MAILBOX_NAME_SIZE - 1, "%d", node_id);
183 * \brief Frees the memory used by a task.
184 * \param task the MSG task to destroy
186 static void task_free(void* task)
188 // TODO add a parameter data_free_function to MSG_task_create?
189 xbt_free(MSG_task_get_data(task));
190 MSG_task_destroy(task);
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)) {
201 VERB0("My finger table:");
202 VERB0("Start | Succ ");
203 for (i = 0; i < nb_bits; i++) {
204 VERB2(" %3d | %3d ", (node->id + powers2[i]) % nb_keys, node->fingers[i].id);
206 VERB1("Predecessor: %d", node->pred_id);
211 * \brief Sets a finger of the current node.
212 * \param node the current node
213 * \param finger_index index of the finger to set (0 to nb_bits - 1)
214 * \param id the id to set for this finger
216 static void set_finger(node_t node, int finger_index, int id)
218 if (id != node->fingers[finger_index].id) {
219 node->fingers[finger_index].id = id;
220 get_mailbox(id, node->fingers[finger_index].mailbox);
221 node->last_change_date = MSG_get_clock();
222 DEBUG2("My new finger #%d is %d", finger_index, id);
227 * \brief Sets the predecessor of the current node.
228 * \param node the current node
229 * \param id the id to predecessor, or -1 to unset the predecessor
231 static void set_predecessor(node_t node, int predecessor_id)
233 if (predecessor_id != node->pred_id) {
234 node->pred_id = predecessor_id;
236 if (predecessor_id != -1) {
237 get_mailbox(predecessor_id, node->pred_mailbox);
239 node->last_change_date = MSG_get_clock();
241 DEBUG1("My new predecessor is %d", predecessor_id);
246 * \brief Node Function
249 * - the id of a guy I know in the system (except for the first node)
250 * - the time to sleep before I join (except for the first node)
252 int node(int argc, char *argv[])
254 /* Reduce the run size for the MC */
256 periodic_stabilize_delay = 8;
257 periodic_fix_fingers_delay = 8;
258 periodic_check_predecessor_delay = 8;
261 double init_time = MSG_get_clock();
262 m_task_t task_received = NULL;
264 int join_success = 0;
266 double next_stabilize_date = init_time + periodic_stabilize_delay;
267 double next_fix_fingers_date = init_time + periodic_fix_fingers_delay;
268 double next_check_predecessor_date = init_time + periodic_check_predecessor_delay;
269 double next_lookup_date = init_time + periodic_lookup_delay;
271 xbt_assert0(argc == 3 || argc == 5, "Wrong number of arguments for this node");
273 // initialize my node
275 node.id = atoi(argv[1]);
276 get_mailbox(node.id, node.mailbox);
277 node.next_finger_to_fix = 0;
278 node.fingers = xbt_new0(s_finger_t, nb_bits);
279 node.last_change_date = init_time;
281 for (i = 0; i < nb_bits; i++) {
282 node.fingers[i].id = -1;
283 set_finger(&node, i, node.id);
286 if (argc == 3) { // first ring
287 deadline = atof(argv[2]);
292 int known_id = atoi(argv[2]);
293 //double sleep_time = atof(argv[3]);
294 deadline = atof(argv[4]);
297 // sleep before starting
298 DEBUG1("Let's sleep during %f", sleep_time);
299 MSG_process_sleep(sleep_time);
301 DEBUG0("Hey! Let's join the system.");
303 join_success = join(&node, known_id);
307 while (MSG_get_clock() < init_time + deadline
308 // && MSG_get_clock() < node.last_change_date + 1000
309 && MSG_get_clock() < max_simulation_time) {
311 if (node.comm_receive == NULL) {
312 task_received = NULL;
313 node.comm_receive = MSG_task_irecv(&task_received, node.mailbox);
314 // FIXME: do not make MSG_task_irecv() calls from several functions
317 if (!MSG_comm_test(node.comm_receive)) {
319 // no task was received: make some periodic calls
320 if (MSG_get_clock() >= next_stabilize_date) {
322 next_stabilize_date = MSG_get_clock() + periodic_stabilize_delay;
324 else if (MSG_get_clock() >= next_fix_fingers_date) {
326 next_fix_fingers_date = MSG_get_clock() + periodic_fix_fingers_delay;
328 else if (MSG_get_clock() >= next_check_predecessor_date) {
329 check_predecessor(&node);
330 next_check_predecessor_date = MSG_get_clock() + periodic_check_predecessor_delay;
332 else if (MSG_get_clock() >= next_lookup_date) {
333 random_lookup(&node);
334 next_lookup_date = MSG_get_clock() + periodic_lookup_delay;
337 // nothing to do: sleep for a while
338 MSG_process_sleep(5);
342 // a transfer has occured
344 MSG_error_t status = MSG_comm_get_status(node.comm_receive);
346 if (status != MSG_OK) {
347 DEBUG0("Failed to receive a task. Nevermind.");
348 node.comm_receive = NULL;
351 // the task was successfully received
352 MSG_comm_destroy(node.comm_receive);
353 node.comm_receive = NULL;
354 handle_task(&node, task_received);
358 // see if some communications are finished
360 while ((index = MSG_comm_testany(node.comms)) != -1) {
361 comm_send = xbt_dynar_get_as(node.comms, index, msg_comm_t);
362 MSG_error_t status = MSG_comm_get_status(comm_send);
363 xbt_dynar_remove_at(node.comms, index, &comm_send);
364 DEBUG3("Communication %p is finished with status %d, dynar size is now %lu",
365 comm_send, status, xbt_dynar_length(node.comms));
366 m_task_t task = MSG_comm_get_task(comm_send);
367 MSG_comm_destroy(comm_send);
368 if (status != MSG_OK) {
369 task_data_destroy(MSG_task_get_data(task));
370 MSG_task_destroy(task);
376 // clean unfinished comms sent
377 /* unsigned int cursor;
378 xbt_dynar_foreach(node.comms, cursor, comm_send) {
379 m_task_t task = MSG_comm_get_task(comm_send);
380 MSG_task_cancel(task);
381 task_data_destroy(MSG_task_get_data(task));
382 MSG_task_destroy(task);
383 MSG_comm_destroy(comm_send);
384 // FIXME: the task is actually not destroyed because MSG thinks that the other side (whose process is dead) is still using it
391 // stop the simulation
392 xbt_free(node.fingers);
397 * \brief This function is called when the current node receives a task.
398 * \param node the current node
399 * \param task the task to handle (don't touch it then:
400 * it will be destroyed, reused or forwarded)
402 static void handle_task(node_t node, m_task_t task) {
404 DEBUG1("Handling task %p", task);
405 char mailbox[MAILBOX_NAME_SIZE];
406 task_data_t task_data = (task_data_t) MSG_task_get_data(task);
407 e_task_type_t type = task_data->type;
411 case TASK_FIND_SUCCESSOR:
412 DEBUG2("Receiving a 'Find Successor' request from %s for id %d",
413 task_data->issuer_host_name, task_data->request_id);
414 // is my successor the successor?
415 if (is_in_interval(task_data->request_id, node->id + 1, node->fingers[0].id)) {
416 task_data->type = TASK_FIND_SUCCESSOR_ANSWER;
417 task_data->answer_id = node->fingers[0].id;
418 DEBUG4("Sending back a 'Find Successor Answer' to %s (mailbox %s): the successor of %d is %d",
419 task_data->issuer_host_name,
420 task_data->answer_to,
421 task_data->request_id, task_data->answer_id);
422 MSG_task_dsend(task, task_data->answer_to, task_free);
425 // otherwise, forward the request to the closest preceding finger in my table
426 int closest = closest_preceding_node(node, task_data->request_id);
427 DEBUG2("Forwarding the 'Find Successor' request for id %d to my closest preceding finger %d",
428 task_data->request_id, closest);
429 get_mailbox(closest, mailbox);
430 MSG_task_dsend(task, mailbox, task_free);
434 case TASK_GET_PREDECESSOR:
435 DEBUG1("Receiving a 'Get Predecessor' request from %s", task_data->issuer_host_name);
436 task_data->type = TASK_GET_PREDECESSOR_ANSWER;
437 task_data->answer_id = node->pred_id;
438 DEBUG3("Sending back a 'Get Predecessor Answer' to %s via mailbox '%s': my predecessor is %d",
439 task_data->issuer_host_name,
440 task_data->answer_to, task_data->answer_id);
441 MSG_task_dsend(task, task_data->answer_to, task_free);
445 // someone is telling me that he may be my new predecessor
446 DEBUG1("Receiving a 'Notify' request from %s", task_data->issuer_host_name);
447 notify(node, task_data->request_id);
451 case TASK_PREDECESSOR_LEAVING:
452 // my predecessor is about to quit
453 DEBUG1("Receiving a 'Predecessor Leaving' message from %s", task_data->issuer_host_name);
454 // modify my predecessor
455 set_predecessor(node, task_data->request_id);
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);
470 >> notify my new successor
471 >> update my table & predecessors table */
474 case TASK_FIND_SUCCESSOR_ANSWER:
475 case TASK_GET_PREDECESSOR_ANSWER:
476 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[MAILBOX_NAME_SIZE];
601 get_mailbox(ask_to, mailbox);
602 task_data_t req_data = xbt_new0(s_task_data_t, 1);
603 req_data->type = TASK_FIND_SUCCESSOR;
604 req_data->request_id = id;
605 get_mailbox(node->id, req_data->answer_to);
606 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
608 // send a "Find Successor" request to ask_to_id
609 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
610 DEBUG3("Sending a 'Find Successor' request (task %p) to %d for id %d", task_sent, ask_to, id);
611 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
614 DEBUG3("Failed to send the 'Find Successor' request (task %p) to %d for id %d",
615 task_sent, ask_to, id);
616 task_free(task_sent);
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);
637 node->comm_receive = NULL;
640 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
641 DEBUG1("Received a task (%p)", task_received);
642 task_data_t ans_data = MSG_task_get_data(task_received);
645 MC_assert(task_received == task_sent);
648 if (task_received != task_sent) {
649 // this is not the expected answer
650 MSG_comm_destroy(node->comm_receive);
651 node->comm_receive = NULL;
652 handle_task(node, task_received);
655 // this is our answer
656 DEBUG4("Received the answer to my 'Find Successor' request for id %d (task %p): the successor of key %d is %d",
657 ans_data->request_id, task_received, id, ans_data->answer_id);
658 successor = ans_data->answer_id;
660 MSG_comm_destroy(node->comm_receive);
661 node->comm_receive = NULL;
662 task_free(task_received);
672 * \brief Asks another node its predecessor.
673 * \param node the current node
674 * \param ask_to the node to ask to
675 * \return the id of its predecessor node, or -1 if the request failed
676 * (or if the node does not know its predecessor)
678 static int remote_get_predecessor(node_t node, int ask_to)
680 int predecessor_id = -1;
682 char mailbox[MAILBOX_NAME_SIZE];
683 get_mailbox(ask_to, mailbox);
684 task_data_t req_data = xbt_new0(s_task_data_t, 1);
685 req_data->type = TASK_GET_PREDECESSOR;
686 get_mailbox(node->id, req_data->answer_to);
687 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
689 // send a "Get Predecessor" request to ask_to_id
690 DEBUG1("Sending a 'Get Predecessor' request to %d", ask_to);
691 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
692 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
695 DEBUG2("Failed to send the 'Get Predecessor' request (task %p) to %d",
697 task_free(task_sent);
701 // receive the answer
702 DEBUG3("Sent 'Get Predecessor' request (task %p) to %d, waiting for the answer on my mailbox '%s'",
703 task_sent, ask_to, req_data->answer_to);
706 if (node->comm_receive == NULL) { // FIXME simplify this
707 m_task_t task_received = NULL;
708 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
711 res = MSG_comm_wait(node->comm_receive, timeout);
714 DEBUG2("Failed to receive the answer to my 'Get Predecessor' request (task %p): %d",
717 MSG_comm_destroy(node->comm_receive);
718 node->comm_receive = NULL;
721 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
722 task_data_t ans_data = MSG_task_get_data(task_received);
725 MC_assert(task_received == task_sent);
728 if (task_received != task_sent) {
729 MSG_comm_destroy(node->comm_receive);
730 node->comm_receive = NULL;
731 handle_task(node, task_received);
734 DEBUG3("Received the answer to my 'Get Predecessor' request (task %p): the predecessor of node %d is %d",
735 task_received, ask_to, ans_data->answer_id);
736 predecessor_id = ans_data->answer_id;
738 MSG_comm_destroy(node->comm_receive);
739 node->comm_receive = NULL;
740 task_free(task_received);
746 return predecessor_id;
750 * \brief Returns the closest preceding finger of an id
751 * with respect to the finger table of the current node.
752 * \param node the current node
753 * \param id the id to find
754 * \return the closest preceding finger of that id
756 int closest_preceding_node(node_t node, int id)
759 for (i = nb_bits - 1; i >= 0; i--) {
760 if (is_in_interval(node->fingers[i].id, node->id + 1, id - 1)) {
761 return node->fingers[i].id;
768 * \brief This function is called periodically. It checks the immediate
769 * successor of the current node.
770 * \param node the current node
772 static void stabilize(node_t node)
774 DEBUG0("Stabilizing node");
776 // get the predecessor of my immediate successor
778 int successor_id = node->fingers[0].id;
779 if (successor_id != node->id) {
780 candidate_id = remote_get_predecessor(node, successor_id);
783 candidate_id = node->pred_id;
786 // this node is a candidate to become my new successor
787 if (candidate_id != -1
788 && is_in_interval(candidate_id, node->id + 1, successor_id - 1)) {
789 set_finger(node, 0, candidate_id);
791 if (successor_id != node->id) {
792 remote_notify(node, successor_id, node->id);
797 * \brief Notifies the current node that its predecessor may have changed.
798 * \param node the current node
799 * \param candidate_id the possible new predecessor
801 static void notify(node_t node, int predecessor_candidate_id) {
803 if (node->pred_id == -1
804 || is_in_interval(predecessor_candidate_id, node->pred_id + 1, node->id - 1)) {
806 set_predecessor(node, predecessor_candidate_id);
807 print_finger_table(node);
810 DEBUG1("I don't have to change my predecessor to %d", predecessor_candidate_id);
815 * \brief Notifies a remote node that its predecessor may have changed.
816 * \param node the current node
817 * \param notify_id id of the node to notify
818 * \param candidate_id the possible new predecessor
820 static void remote_notify(node_t node, int notify_id, int predecessor_candidate_id) {
822 task_data_t req_data = xbt_new0(s_task_data_t, 1);
823 req_data->type = TASK_NOTIFY;
824 req_data->request_id = predecessor_candidate_id;
825 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
827 // send a "Notify" request to notify_id
828 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
829 DEBUG2("Sending a 'Notify' request (task %p) to %d", task, notify_id);
830 char mailbox[MAILBOX_NAME_SIZE];
831 get_mailbox(notify_id, mailbox);
832 MSG_task_dsend(task, mailbox, task_free);
836 * \brief This function is called periodically.
837 * It refreshes the finger table of the current node.
838 * \param node the current node
840 static void fix_fingers(node_t node) {
842 DEBUG0("Fixing fingers");
843 int i = node->next_finger_to_fix;
844 int id = find_successor(node, node->id + powers2[i]);
847 if (id != node->fingers[i].id) {
848 set_finger(node, i, id);
849 print_finger_table(node);
851 node->next_finger_to_fix = (i + 1) % nb_bits;
856 * \brief This function is called periodically.
857 * It checks whether the predecessor has failed
858 * \param node the current node
860 static void check_predecessor(node_t node)
862 DEBUG0("Checking whether my predecessor is alive");
867 * \brief Performs a find successor request to a random id.
868 * \param node the current node
870 static void random_lookup(node_t node)
872 int id = 1337; // TODO pick a pseudorandom id
873 DEBUG1("Making a lookup request for id %d", id);
874 find_successor(node, id);
878 * \brief Main function.
880 int main(int argc, char *argv[])
883 printf("Usage: %s [-nb_bits=n] [-timeout=t] platform_file deployment_file\n", argv[0]);
884 printf("example: %s ../msg_platform.xml chord.xml\n", argv[0]);
888 MSG_global_init(&argc, argv);
890 char **options = &argv[1];
891 while (!strncmp(options[0], "-", 1)) {
893 int length = strlen("-nb_bits=");
894 if (!strncmp(options[0], "-nb_bits=", length) && strlen(options[0]) > length) {
895 nb_bits = atoi(options[0] + length);
896 DEBUG1("Set nb_bits to %d", nb_bits);
900 length = strlen("-timeout=");
901 if (!strncmp(options[0], "-timeout=", length) && strlen(options[0]) > length) {
902 timeout = atoi(options[0] + length);
903 DEBUG1("Set timeout to %d", timeout);
906 xbt_assert1(0, "Invalid chord option '%s'", options[0]);
912 const char* platform_file = options[0];
913 const char* application_file = options[1];
917 MSG_set_channel_number(0);
918 MSG_create_environment(platform_file);
920 MSG_function_register("node", node);
921 MSG_launch_application(application_file);
923 MSG_error_t res = MSG_main();
924 INFO1("Simulation time: %g", MSG_get_clock());