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;
30 extern long int smx_total_comms;
35 typedef struct finger {
37 char mailbox[MAILBOX_NAME_SIZE]; // string representation of the id
38 } s_finger_t, *finger_t;
45 char mailbox[MAILBOX_NAME_SIZE]; // my mailbox name (string representation of the id)
46 s_finger_t *fingers; // finger table, of size nb_bits (fingers[0] is my successor)
47 int pred_id; // predecessor id
48 char pred_mailbox[MAILBOX_NAME_SIZE]; // predecessor's mailbox name
49 int next_finger_to_fix; // index of the next finger to fix in fix_fingers()
50 msg_comm_t comm_receive; // current communication to receive
51 double last_change_date; // last time I changed a finger or my predecessor
55 * Types of tasks exchanged between nodes.
59 TASK_FIND_SUCCESSOR_ANSWER,
61 TASK_GET_PREDECESSOR_ANSWER,
63 TASK_SUCCESSOR_LEAVING,
64 TASK_PREDECESSOR_LEAVING
68 * Data attached with the tasks sent and received
70 typedef struct task_data {
71 e_task_type_t type; // type of task
72 int request_id; // id paramater (used by some types of tasks)
73 int request_finger; // finger parameter (used by some types of tasks)
74 int answer_id; // answer (used by some types of tasks)
75 char answer_to[MAILBOX_NAME_SIZE]; // mailbox to send an answer to (if any)
76 const char* issuer_host_name; // used for logging
77 } s_task_data_t, *task_data_t;
82 static void chord_initialize(void);
83 static int normalize(int id);
84 static int is_in_interval(int id, int start, int end);
85 static void get_mailbox(int host_id, char* mailbox);
86 static void task_free(void* task);
87 static void print_finger_table(node_t node);
88 static void set_finger(node_t node, int finger_index, int id);
89 static void set_predecessor(node_t node, int predecessor_id);
92 static int node(int argc, char *argv[]);
93 static void handle_task(node_t node, m_task_t task);
96 static void create(node_t node);
97 static int join(node_t node, int known_id);
98 static void leave(node_t node);
99 static int find_successor(node_t node, int id);
100 static int remote_find_successor(node_t node, int ask_to_id, int id);
101 static int remote_get_predecessor(node_t node, int ask_to_id);
102 static int closest_preceding_node(node_t node, int id);
103 static void stabilize(node_t node);
104 static void notify(node_t node, int predecessor_candidate_id);
105 static void remote_notify(node_t node, int notify_to, int predecessor_candidate_id);
106 static void fix_fingers(node_t node);
107 static void check_predecessor(node_t node);
108 static void random_lookup(node_t);
109 static void quit_notify(node_t node, int to);
112 * \brief Global initialization of the Chord simulation.
114 static void chord_initialize(void)
116 // compute the powers of 2 once for all
117 powers2 = xbt_new(int, nb_bits);
120 for (i = 0; i < nb_bits; i++) {
125 DEBUG1("Sets nb_keys to %d", nb_keys);
129 * \brief Turns an id into an equivalent id in [0, nb_keys).
131 * \return the corresponding normalized id
133 static int normalize(int id)
135 // like id % nb_keys, but works with negatives numbers (and faster)
136 return id & (nb_keys - 1);
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 * \param mailbox pointer to where the mailbox name should be written
177 * (there must be enough space)
179 static void get_mailbox(int node_id, char* mailbox)
181 snprintf(mailbox, MAILBOX_NAME_SIZE - 1, "%d", node_id);
185 * \brief Frees the memory used by a task.
186 * \param task the MSG task to destroy
188 static void task_free(void* task)
190 // TODO add a parameter data_free_function to MSG_task_create?
191 xbt_free(MSG_task_get_data(task));
192 MSG_task_destroy(task);
196 * \brief Displays the finger table of a node.
199 static void print_finger_table(node_t node)
201 if (XBT_LOG_ISENABLED(msg_chord, xbt_log_priority_verbose)) {
203 VERB0("My finger table:");
204 VERB0("Start | Succ ");
205 for (i = 0; i < nb_bits; i++) {
206 VERB2(" %3d | %3d ", (node->id + powers2[i]) % 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 get_mailbox(id, node->fingers[finger_index].mailbox);
223 node->last_change_date = MSG_get_clock();
224 DEBUG2("My new finger #%d is %d", finger_index, id);
229 * \brief Sets the predecessor of the current node.
230 * \param node the current node
231 * \param id the id to predecessor, or -1 to unset the predecessor
233 static void set_predecessor(node_t node, int predecessor_id)
235 if (predecessor_id != node->pred_id) {
236 node->pred_id = predecessor_id;
238 if (predecessor_id != -1) {
239 get_mailbox(predecessor_id, node->pred_mailbox);
241 node->last_change_date = MSG_get_clock();
243 DEBUG1("My new predecessor is %d", predecessor_id);
248 * \brief Node Function
251 * - the id of a guy I know in the system (except for the first node)
252 * - the time to sleep before I join (except for the first node)
254 int node(int argc, char *argv[])
256 /* Reduce the run size for the MC */
258 periodic_stabilize_delay = 8;
259 periodic_fix_fingers_delay = 8;
260 periodic_check_predecessor_delay = 8;
263 double init_time = MSG_get_clock();
264 m_task_t task_received = NULL;
266 int join_success = 0;
268 double next_stabilize_date = init_time + periodic_stabilize_delay;
269 double next_fix_fingers_date = init_time + periodic_fix_fingers_delay;
270 double next_check_predecessor_date = init_time + periodic_check_predecessor_delay;
271 double next_lookup_date = init_time + periodic_lookup_delay;
273 xbt_assert0(argc == 3 || argc == 5, "Wrong number of arguments for this node");
275 // initialize my node
277 node.id = atoi(argv[1]);
278 get_mailbox(node.id, node.mailbox);
279 node.next_finger_to_fix = 0;
280 node.fingers = xbt_new0(s_finger_t, nb_bits);
281 node.last_change_date = init_time;
283 for (i = 0; i < nb_bits; i++) {
284 node.fingers[i].id = -1;
285 set_finger(&node, i, node.id);
288 if (argc == 3) { // first ring
289 deadline = atof(argv[2]);
294 int known_id = atoi(argv[2]);
295 //double sleep_time = atof(argv[3]);
296 deadline = atof(argv[4]);
299 // sleep before starting
300 DEBUG1("Let's sleep during %f", sleep_time);
301 MSG_process_sleep(sleep_time);
303 DEBUG0("Hey! Let's join the system.");
305 join_success = join(&node, known_id);
309 while (MSG_get_clock() < init_time + deadline
310 // && MSG_get_clock() < node.last_change_date + 1000
311 && MSG_get_clock() < max_simulation_time) {
313 if (node.comm_receive == NULL) {
314 task_received = NULL;
315 node.comm_receive = MSG_task_irecv(&task_received, node.mailbox);
316 // FIXME: do not make MSG_task_irecv() calls from several functions
319 if (!MSG_comm_test(node.comm_receive)) {
321 // no task was received: make some periodic calls
322 if (MSG_get_clock() >= next_stabilize_date) {
324 next_stabilize_date = MSG_get_clock() + periodic_stabilize_delay;
326 else if (MSG_get_clock() >= next_fix_fingers_date) {
328 next_fix_fingers_date = MSG_get_clock() + periodic_fix_fingers_delay;
330 else if (MSG_get_clock() >= next_check_predecessor_date) {
331 check_predecessor(&node);
332 next_check_predecessor_date = MSG_get_clock() + periodic_check_predecessor_delay;
334 else if (MSG_get_clock() >= next_lookup_date) {
335 random_lookup(&node);
336 next_lookup_date = MSG_get_clock() + periodic_lookup_delay;
339 // nothing to do: sleep for a while
340 MSG_process_sleep(5);
344 // a transfer has occured
346 MSG_error_t status = MSG_comm_get_status(node.comm_receive);
348 if (status != MSG_OK) {
349 DEBUG0("Failed to receive a task. Nevermind.");
350 node.comm_receive = NULL;
353 // the task was successfully received
354 MSG_comm_destroy(node.comm_receive);
355 node.comm_receive = NULL;
356 handle_task(&node, task_received);
360 // see if some communications are finished
362 while ((index = MSG_comm_testany(node.comms)) != -1) {
363 comm_send = xbt_dynar_get_as(node.comms, index, msg_comm_t);
364 MSG_error_t status = MSG_comm_get_status(comm_send);
365 xbt_dynar_remove_at(node.comms, index, &comm_send);
366 DEBUG3("Communication %p is finished with status %d, dynar size is now %lu",
367 comm_send, status, xbt_dynar_length(node.comms));
368 m_task_t task = MSG_comm_get_task(comm_send);
369 MSG_comm_destroy(comm_send);
370 if (status != MSG_OK) {
371 task_data_destroy(MSG_task_get_data(task));
372 MSG_task_destroy(task);
378 // clean unfinished comms sent
379 /* unsigned int cursor;
380 xbt_dynar_foreach(node.comms, cursor, comm_send) {
381 m_task_t task = MSG_comm_get_task(comm_send);
382 MSG_task_cancel(task);
383 task_data_destroy(MSG_task_get_data(task));
384 MSG_task_destroy(task);
385 MSG_comm_destroy(comm_send);
386 // FIXME: the task is actually not destroyed because MSG thinks that the other side (whose process is dead) is still using it
393 // stop the simulation
394 xbt_free(node.fingers);
395 INFO1("Messages created: %lu", smx_total_comms);
400 * \brief This function is called when the current node receives a task.
401 * \param node the current node
402 * \param task the task to handle (don't touch it then:
403 * it will be destroyed, reused or forwarded)
405 static void handle_task(node_t node, m_task_t task) {
407 DEBUG1("Handling task %p", task);
408 char mailbox[MAILBOX_NAME_SIZE];
409 task_data_t task_data = (task_data_t) MSG_task_get_data(task);
410 e_task_type_t type = task_data->type;
414 case TASK_FIND_SUCCESSOR:
415 DEBUG2("Receiving a 'Find Successor' request from %s for id %d",
416 task_data->issuer_host_name, task_data->request_id);
417 // is my successor the successor?
418 if (is_in_interval(task_data->request_id, node->id + 1, node->fingers[0].id)) {
419 task_data->type = TASK_FIND_SUCCESSOR_ANSWER;
420 task_data->answer_id = node->fingers[0].id;
421 DEBUG4("Sending back a 'Find Successor Answer' to %s (mailbox %s): the successor of %d is %d",
422 task_data->issuer_host_name,
423 task_data->answer_to,
424 task_data->request_id, task_data->answer_id);
425 MSG_task_dsend(task, task_data->answer_to, task_free);
428 // otherwise, forward the request to the closest preceding finger in my table
429 int closest = closest_preceding_node(node, task_data->request_id);
430 DEBUG2("Forwarding the 'Find Successor' request for id %d to my closest preceding finger %d",
431 task_data->request_id, closest);
432 get_mailbox(closest, mailbox);
433 MSG_task_dsend(task, mailbox, task_free);
437 case TASK_GET_PREDECESSOR:
438 DEBUG1("Receiving a 'Get Predecessor' request from %s", task_data->issuer_host_name);
439 task_data->type = TASK_GET_PREDECESSOR_ANSWER;
440 task_data->answer_id = node->pred_id;
441 DEBUG3("Sending back a 'Get Predecessor Answer' to %s via mailbox '%s': my predecessor is %d",
442 task_data->issuer_host_name,
443 task_data->answer_to, task_data->answer_id);
444 MSG_task_dsend(task, task_data->answer_to, task_free);
448 // someone is telling me that he may be my new predecessor
449 DEBUG1("Receiving a 'Notify' request from %s", task_data->issuer_host_name);
450 notify(node, task_data->request_id);
454 case TASK_PREDECESSOR_LEAVING:
455 // my predecessor is about to quit
456 DEBUG1("Receiving a 'Predecessor Leaving' message from %s", task_data->issuer_host_name);
457 // modify my predecessor
458 set_predecessor(node, task_data->request_id);
461 >> notify my new predecessor
462 >> send a notify_predecessors !!
466 case TASK_SUCCESSOR_LEAVING:
467 // my successor is about to quit
468 DEBUG1("Receiving a 'Successor Leaving' message from %s", task_data->issuer_host_name);
469 // modify my successor FIXME : this should be implicit ?
470 set_finger(node, 0, task_data->request_id);
473 >> notify my new successor
474 >> update my table & predecessors table */
477 case TASK_FIND_SUCCESSOR_ANSWER:
478 case TASK_GET_PREDECESSOR_ANSWER:
479 DEBUG2("Ignoring unexpected task of type %d (%p)", type, task);
486 * \brief Initializes the current node as the first one of the system.
487 * \param node the current node
489 static void create(node_t node)
491 DEBUG0("Create a new Chord ring...");
492 set_predecessor(node, -1); // -1 means that I have no predecessor
493 print_finger_table(node);
497 * \brief Makes the current node join the ring, knowing the id of a node
498 * already in the ring
499 * \param node the current node
500 * \param known_id id of a node already in the ring
501 * \return 1 if the join operation succeeded, 0 otherwise
503 static int join(node_t node, int known_id)
505 INFO2("Joining the ring with id %d, knowing node %d", node->id, known_id);
506 set_predecessor(node, -1); // no predecessor (yet)
509 for (i = 0; i < nb_bits; i++) {
510 set_finger(node, i, known_id);
513 int successor_id = remote_find_successor(node, known_id, node->id);
514 if (successor_id == -1) {
515 INFO0("Cannot join the ring.");
518 set_finger(node, 0, successor_id);
519 print_finger_table(node);
522 return successor_id != -1;
526 * \brief Makes the current node quit the system
527 * \param node the current node
529 static void leave(node_t node)
531 DEBUG0("Well Guys! I Think it's time for me to quit ;)");
532 quit_notify(node, 1); // notify to my successor ( >>> 1 );
533 quit_notify(node, -1); // notify my predecessor ( >>> -1);
538 * \brief Notifies the successor or the predecessor of the current node
540 * \param node the current node
541 * \param to 1 to notify the successor, -1 to notify the predecessor
542 * FIXME: notify both nodes with only one call
544 static void quit_notify(node_t node, int to)
547 task_data_t req_data = xbt_new0(s_task_data_t, 1);
548 req_data->request_id = node->id;
549 req_data->successor_id = node->fingers[0].id;
550 req_data->pred_id = node->pred_id;
551 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
552 req_data->answer_to = NULL;
553 const char* task_name = NULL;
554 const char* to_mailbox = NULL;
555 if (to == 1) { // notify my successor
556 to_mailbox = node->fingers[0].mailbox;
557 INFO2("Telling my Successor %d about my departure via mailbox %s",
558 node->fingers[0].id, to_mailbox);
559 req_data->type = TASK_PREDECESSOR_LEAVING;
561 else if (to == -1) { // notify my predecessor
563 if (node->pred_id == -1) {
567 to_mailbox = node->pred_mailbox;
568 INFO2("Telling my Predecessor %d about my departure via mailbox %s",
569 node->pred_id, to_mailbox);
570 req_data->type = TASK_SUCCESSOR_LEAVING;
572 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
573 //char* mailbox = get_mailbox(to_mailbox);
574 msg_comm_t comm = MSG_task_isend(task, to_mailbox);
575 xbt_dynar_push(node->comms, &comm);
580 * \brief Makes the current node find the successor node of an id.
581 * \param node the current node
582 * \param id the id to find
583 * \return the id of the successor node, or -1 if the request failed
585 static int find_successor(node_t node, int id)
587 // is my successor the successor?
588 if (is_in_interval(id, node->id + 1, node->fingers[0].id)) {
589 return node->fingers[0].id;
592 // otherwise, ask the closest preceding finger in my table
593 int closest = closest_preceding_node(node, id);
594 return remote_find_successor(node, closest, id);
598 * \brief Asks another node the successor node of an id.
599 * \param node the current node
600 * \param ask_to the node to ask to
601 * \param id the id to find
602 * \return the id of the successor node, or -1 if the request failed
604 static int remote_find_successor(node_t node, int ask_to, int id)
608 char mailbox[MAILBOX_NAME_SIZE];
609 get_mailbox(ask_to, mailbox);
610 task_data_t req_data = xbt_new0(s_task_data_t, 1);
611 req_data->type = TASK_FIND_SUCCESSOR;
612 req_data->request_id = id;
613 get_mailbox(node->id, req_data->answer_to);
614 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
616 // send a "Find Successor" request to ask_to_id
617 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
618 DEBUG3("Sending a 'Find Successor' request (task %p) to %d for id %d", task_sent, ask_to, id);
619 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
622 DEBUG3("Failed to send the 'Find Successor' request (task %p) to %d for id %d",
623 task_sent, ask_to, id);
624 task_free(task_sent);
628 // receive the answer
629 DEBUG3("Sent a 'Find Successor' request (task %p) to %d for key %d, waiting for the answer",
630 task_sent, ask_to, id);
633 if (node->comm_receive == NULL) {
634 m_task_t task_received = NULL;
635 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
638 res = MSG_comm_wait(node->comm_receive, timeout);
641 DEBUG2("Failed to receive the answer to my 'Find Successor' request (task %p): %d",
644 MSG_comm_destroy(node->comm_receive);
645 node->comm_receive = NULL;
648 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
649 DEBUG1("Received a task (%p)", task_received);
650 task_data_t ans_data = MSG_task_get_data(task_received);
653 MC_assert(task_received == task_sent);
656 if (task_received != task_sent) {
657 // this is not the expected answer
658 MSG_comm_destroy(node->comm_receive);
659 node->comm_receive = NULL;
660 handle_task(node, task_received);
663 // this is our answer
664 DEBUG4("Received the answer to my 'Find Successor' request for id %d (task %p): the successor of key %d is %d",
665 ans_data->request_id, task_received, id, ans_data->answer_id);
666 successor = ans_data->answer_id;
668 MSG_comm_destroy(node->comm_receive);
669 node->comm_receive = NULL;
670 task_free(task_received);
680 * \brief Asks another node its predecessor.
681 * \param node the current node
682 * \param ask_to the node to ask to
683 * \return the id of its predecessor node, or -1 if the request failed
684 * (or if the node does not know its predecessor)
686 static int remote_get_predecessor(node_t node, int ask_to)
688 int predecessor_id = -1;
690 char mailbox[MAILBOX_NAME_SIZE];
691 get_mailbox(ask_to, mailbox);
692 task_data_t req_data = xbt_new0(s_task_data_t, 1);
693 req_data->type = TASK_GET_PREDECESSOR;
694 get_mailbox(node->id, req_data->answer_to);
695 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
697 // send a "Get Predecessor" request to ask_to_id
698 DEBUG1("Sending a 'Get Predecessor' request to %d", ask_to);
699 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
700 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
703 DEBUG2("Failed to send the 'Get Predecessor' request (task %p) to %d",
705 task_free(task_sent);
709 // receive the answer
710 DEBUG3("Sent 'Get Predecessor' request (task %p) to %d, waiting for the answer on my mailbox '%s'",
711 task_sent, ask_to, req_data->answer_to);
714 if (node->comm_receive == NULL) { // FIXME simplify this
715 m_task_t task_received = NULL;
716 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
719 res = MSG_comm_wait(node->comm_receive, timeout);
722 DEBUG2("Failed to receive the answer to my 'Get Predecessor' request (task %p): %d",
725 MSG_comm_destroy(node->comm_receive);
726 node->comm_receive = NULL;
729 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
730 task_data_t ans_data = MSG_task_get_data(task_received);
733 MC_assert(task_received == task_sent);
736 if (task_received != task_sent) {
737 MSG_comm_destroy(node->comm_receive);
738 node->comm_receive = NULL;
739 handle_task(node, task_received);
742 DEBUG3("Received the answer to my 'Get Predecessor' request (task %p): the predecessor of node %d is %d",
743 task_received, ask_to, ans_data->answer_id);
744 predecessor_id = ans_data->answer_id;
746 MSG_comm_destroy(node->comm_receive);
747 node->comm_receive = NULL;
748 task_free(task_received);
754 return predecessor_id;
758 * \brief Returns the closest preceding finger of an id
759 * with respect to the finger table of the current node.
760 * \param node the current node
761 * \param id the id to find
762 * \return the closest preceding finger of that id
764 int closest_preceding_node(node_t node, int id)
767 for (i = nb_bits - 1; i >= 0; i--) {
768 if (is_in_interval(node->fingers[i].id, node->id + 1, id - 1)) {
769 return node->fingers[i].id;
776 * \brief This function is called periodically. It checks the immediate
777 * successor of the current node.
778 * \param node the current node
780 static void stabilize(node_t node)
782 DEBUG0("Stabilizing node");
784 // get the predecessor of my immediate successor
786 int successor_id = node->fingers[0].id;
787 if (successor_id != node->id) {
788 candidate_id = remote_get_predecessor(node, successor_id);
791 candidate_id = node->pred_id;
794 // this node is a candidate to become my new successor
795 if (candidate_id != -1
796 && is_in_interval(candidate_id, node->id + 1, successor_id - 1)) {
797 set_finger(node, 0, candidate_id);
799 if (successor_id != node->id) {
800 remote_notify(node, successor_id, node->id);
805 * \brief Notifies the current node that its predecessor may have changed.
806 * \param node the current node
807 * \param candidate_id the possible new predecessor
809 static void notify(node_t node, int predecessor_candidate_id) {
811 if (node->pred_id == -1
812 || is_in_interval(predecessor_candidate_id, node->pred_id + 1, node->id - 1)) {
814 set_predecessor(node, predecessor_candidate_id);
815 print_finger_table(node);
818 DEBUG1("I don't have to change my predecessor to %d", predecessor_candidate_id);
823 * \brief Notifies a remote node that its predecessor may have changed.
824 * \param node the current node
825 * \param notify_id id of the node to notify
826 * \param candidate_id the possible new predecessor
828 static void remote_notify(node_t node, int notify_id, int predecessor_candidate_id) {
830 task_data_t req_data = xbt_new0(s_task_data_t, 1);
831 req_data->type = TASK_NOTIFY;
832 req_data->request_id = predecessor_candidate_id;
833 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
835 // send a "Notify" request to notify_id
836 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
837 DEBUG2("Sending a 'Notify' request (task %p) to %d", task, notify_id);
838 char mailbox[MAILBOX_NAME_SIZE];
839 get_mailbox(notify_id, mailbox);
840 MSG_task_dsend(task, mailbox, task_free);
844 * \brief This function is called periodically.
845 * It refreshes the finger table of the current node.
846 * \param node the current node
848 static void fix_fingers(node_t node) {
850 DEBUG0("Fixing fingers");
851 int i = node->next_finger_to_fix;
852 int id = find_successor(node, node->id + powers2[i]);
855 if (id != node->fingers[i].id) {
856 set_finger(node, i, id);
857 print_finger_table(node);
859 node->next_finger_to_fix = (i + 1) % nb_bits;
864 * \brief This function is called periodically.
865 * It checks whether the predecessor has failed
866 * \param node the current node
868 static void check_predecessor(node_t node)
870 DEBUG0("Checking whether my predecessor is alive");
875 * \brief Performs a find successor request to a random id.
876 * \param node the current node
878 static void random_lookup(node_t node)
880 int id = 1337; // TODO pick a pseudorandom id
881 DEBUG1("Making a lookup request for id %d", id);
882 find_successor(node, id);
886 * \brief Main function.
888 int main(int argc, char *argv[])
891 printf("Usage: %s [-nb_bits=n] [-timeout=t] platform_file deployment_file\n", argv[0]);
892 printf("example: %s ../msg_platform.xml chord.xml\n", argv[0]);
896 MSG_global_init(&argc, argv);
898 char **options = &argv[1];
899 while (!strncmp(options[0], "-", 1)) {
901 int length = strlen("-nb_bits=");
902 if (!strncmp(options[0], "-nb_bits=", length) && strlen(options[0]) > length) {
903 nb_bits = atoi(options[0] + length);
904 DEBUG1("Set nb_bits to %d", nb_bits);
908 length = strlen("-timeout=");
909 if (!strncmp(options[0], "-timeout=", length) && strlen(options[0]) > length) {
910 timeout = atoi(options[0] + length);
911 DEBUG1("Set timeout to %d", timeout);
914 xbt_assert1(0, "Invalid chord option '%s'", options[0]);
920 const char* platform_file = options[0];
921 const char* application_file = options[1];
925 MSG_set_channel_number(0);
926 MSG_create_environment(platform_file);
928 MSG_function_register("node", node);
929 MSG_launch_application(application_file);
931 MSG_error_t res = MSG_main();
932 INFO1("Simulated time: %g", MSG_get_clock());