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 xbt_dynar_t comms; // current communications being sent
50 double last_change_date; // last time I changed a finger or my predecessor
54 * Types of tasks exchanged between nodes.
58 TASK_FIND_SUCCESSOR_ANSWER,
60 TASK_GET_PREDECESSOR_ANSWER,
62 TASK_SUCCESSOR_LEAVING,
63 TASK_PREDECESSOR_LEAVING
67 * Data attached with the tasks sent and received
69 typedef struct task_data {
70 e_task_type_t type; // type of task
71 int request_id; // id paramater (used by some types of tasks)
72 int request_finger; // finger parameter (used by some types of tasks)
73 int answer_id; // answer (used by some types of tasks)
74 char answer_to[MAILBOX_NAME_SIZE]; // mailbox to send an answer to (if any)
75 const char* issuer_host_name; // used for logging
76 } s_task_data_t, *task_data_t;
81 static void chord_initialize(void);
82 static int normalize(int id);
83 static int is_in_interval(int id, int start, int end);
84 static void get_mailbox(int host_id, char* mailbox);
85 static void task_data_destroy(task_data_t task_data);
86 static void print_finger_table(node_t node);
87 static void set_finger(node_t node, int finger_index, int id);
88 static void set_predecessor(node_t node, int predecessor_id);
91 static int node(int argc, char *argv[]);
92 static void handle_task(node_t node, m_task_t task);
95 static void create(node_t node);
96 static int join(node_t node, int known_id);
97 static void leave(node_t node);
98 static int find_successor(node_t node, int id);
99 static int remote_find_successor(node_t node, int ask_to_id, int id);
100 static int remote_get_predecessor(node_t node, int ask_to_id);
101 static int closest_preceding_node(node_t node, int id);
102 static void stabilize(node_t node);
103 static void notify(node_t node, int predecessor_candidate_id);
104 static void remote_notify(node_t node, int notify_to, int predecessor_candidate_id);
105 static void fix_fingers(node_t node);
106 static void check_predecessor(node_t node);
107 static void random_lookup(node_t);
108 static void quit_notify(node_t node, int to);
111 * \brief Global initialization of the Chord simulation.
113 static void chord_initialize(void)
115 // compute the powers of 2 once for all
116 powers2 = xbt_new(int, nb_bits);
119 for (i = 0; i < nb_bits; i++) {
124 DEBUG1("Sets nb_keys to %d", nb_keys);
128 * \brief Turns an id into an equivalent id in [0, nb_keys).
130 * \return the corresponding normalized id
132 static int normalize(int id)
134 // like id % nb_keys, but works with negatives numbers (and faster)
135 return id & (nb_keys - 1);
139 * \brief Returns whether a id belongs to the interval [start, end].
141 * The parameters are noramlized to make sure they are between 0 and nb_keys - 1).
142 * 1 belongs to [62, 3]
143 * 1 does not belong to [3, 62]
144 * 63 belongs to [62, 3]
145 * 63 does not belong to [3, 62]
146 * 24 belongs to [21, 29]
147 * 24 does not belong to [29, 21]
149 * \param id id to check
150 * \param start lower bound
151 * \param end upper bound
152 * \return a non-zero value if id in in [start, end]
154 static int is_in_interval(int id, int start, int end)
157 start = normalize(start);
158 end = normalize(end);
160 // make sure end >= start and id >= start
173 * \brief Gets the mailbox name of a host given its chord id.
174 * \param node_id id of a node
175 * \param mailbox pointer to where the mailbox name should be written
176 * (there must be enough space)
178 static void get_mailbox(int node_id, char* mailbox)
180 snprintf(mailbox, MAILBOX_NAME_SIZE - 1, "%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)
193 * \brief Displays the finger table of a node.
196 static void print_finger_table(node_t node)
198 if (XBT_LOG_ISENABLED(msg_chord, xbt_log_priority_verbose)) {
200 VERB0("My finger table:");
201 VERB0("Start | Succ ");
202 for (i = 0; i < nb_bits; i++) {
203 VERB2(" %3d | %3d ", (node->id + powers2[i]) % nb_keys, node->fingers[i].id);
205 VERB1("Predecessor: %d", node->pred_id);
210 * \brief Sets a finger of the current node.
211 * \param node the current node
212 * \param finger_index index of the finger to set (0 to nb_bits - 1)
213 * \param id the id to set for this finger
215 static void set_finger(node_t node, int finger_index, int id)
217 if (id != node->fingers[finger_index].id) {
218 node->fingers[finger_index].id = id;
219 get_mailbox(id, node->fingers[finger_index].mailbox);
220 node->last_change_date = MSG_get_clock();
221 DEBUG2("My new finger #%d is %d", finger_index, id);
226 * \brief Sets the predecessor of the current node.
227 * \param node the current node
228 * \param id the id to predecessor, or -1 to unset the predecessor
230 static void set_predecessor(node_t node, int predecessor_id)
232 if (predecessor_id != node->pred_id) {
233 node->pred_id = predecessor_id;
235 if (predecessor_id != -1) {
236 get_mailbox(predecessor_id, node->pred_mailbox);
238 node->last_change_date = MSG_get_clock();
240 DEBUG1("My new predecessor is %d", predecessor_id);
245 * \brief Node Function
248 * - the id of a guy I know in the system (except for the first node)
249 * - the time to sleep before I join (except for the first node)
251 int node(int argc, char *argv[])
253 double init_time = MSG_get_clock();
254 m_task_t task_received = NULL;
255 msg_comm_t comm_send = NULL;
258 int join_success = 0;
260 double next_stabilize_date = init_time + periodic_stabilize_delay;
261 double next_fix_fingers_date = init_time + periodic_fix_fingers_delay;
262 double next_check_predecessor_date = init_time + periodic_check_predecessor_delay;
263 double next_lookup_date = init_time + periodic_lookup_delay;
265 xbt_assert0(argc == 3 || argc == 5, "Wrong number of arguments for this node");
267 // initialize my node
269 node.id = atoi(argv[1]);
270 get_mailbox(node.id, node.mailbox);
271 node.next_finger_to_fix = 0;
272 node.comms = xbt_dynar_new(sizeof(msg_comm_t), NULL);
273 node.fingers = xbt_new0(s_finger_t, nb_bits);
274 node.last_change_date = init_time;
276 for (i = 0; i < nb_bits; i++) {
277 node.fingers[i].id = -1;
278 set_finger(&node, i, node.id);
281 if (argc == 3) { // first ring
282 deadline = atof(argv[2]);
287 int known_id = atoi(argv[2]);
288 //double sleep_time = atof(argv[3]);
289 deadline = atof(argv[4]);
292 // sleep before starting
293 DEBUG1("Let's sleep during %f", sleep_time);
294 MSG_process_sleep(sleep_time);
296 DEBUG0("Hey! Let's join the system.");
298 join_success = join(&node, known_id);
302 while (MSG_get_clock() < init_time + deadline
303 // && MSG_get_clock() < node.last_change_date + 1000
304 && MSG_get_clock() < max_simulation_time) {
306 if (node.comm_receive == NULL) {
307 task_received = NULL;
308 node.comm_receive = MSG_task_irecv(&task_received, node.mailbox);
309 // FIXME: do not make MSG_task_irecv() calls from several functions
312 if (!MSG_comm_test(node.comm_receive)) {
314 // no task was received: make some periodic calls
315 if (MSG_get_clock() >= next_stabilize_date) {
317 next_stabilize_date = MSG_get_clock() + periodic_stabilize_delay;
319 else if (MSG_get_clock() >= next_fix_fingers_date) {
321 next_fix_fingers_date = MSG_get_clock() + periodic_fix_fingers_delay;
323 else if (MSG_get_clock() >= next_check_predecessor_date) {
324 check_predecessor(&node);
325 next_check_predecessor_date = MSG_get_clock() + periodic_check_predecessor_delay;
327 else if (MSG_get_clock() >= next_lookup_date) {
328 random_lookup(&node);
329 next_lookup_date = MSG_get_clock() + periodic_lookup_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 m_task_t task = MSG_comm_get_task(comm_send);
361 MSG_comm_destroy(comm_send);
362 if (status != MSG_OK) {
363 task_data_destroy(MSG_task_get_data(task));
364 MSG_task_destroy(task);
369 // clean unfinished comms sent
370 /* unsigned int cursor;
371 xbt_dynar_foreach(node.comms, cursor, comm_send) {
372 m_task_t task = MSG_comm_get_task(comm_send);
373 MSG_task_cancel(task);
374 task_data_destroy(MSG_task_get_data(task));
375 MSG_task_destroy(task);
376 MSG_comm_destroy(comm_send);
377 // FIXME: the task is actually not destroyed because MSG thinks that the other side (whose process is dead) is still using it
384 // stop the simulation
385 xbt_dynar_free(&node.comms);
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[MAILBOX_NAME_SIZE];
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 DEBUG4("Sending back a 'Find Successor Answer' to %s (mailbox %s): the successor of %d is %d",
414 task_data->issuer_host_name,
415 task_data->answer_to,
416 task_data->request_id, task_data->answer_id);
417 comm = MSG_task_isend(task, task_data->answer_to);
418 xbt_dynar_push(node->comms, &comm);
421 // otherwise, forward the request to the closest preceding finger in my table
422 int closest = closest_preceding_node(node, task_data->request_id);
423 DEBUG2("Forwarding the 'Find Successor' request for id %d to my closest preceding finger %d",
424 task_data->request_id, closest);
425 get_mailbox(closest, mailbox);
426 comm = MSG_task_isend(task, mailbox);
427 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);
478 task_data_destroy(task_data);
479 MSG_task_destroy(task);
485 * \brief Initializes the current node as the first one of the system.
486 * \param node the current node
488 static void create(node_t node)
490 DEBUG0("Create a new Chord ring...");
491 set_predecessor(node, -1); // -1 means that I have no predecessor
492 print_finger_table(node);
496 * \brief Makes the current node join the ring, knowing the id of a node
497 * already in the ring
498 * \param node the current node
499 * \param known_id id of a node already in the ring
500 * \return 1 if the join operation succeeded, 0 otherwise
502 static int join(node_t node, int known_id)
504 INFO2("Joining the ring with id %d, knowing node %d", node->id, known_id);
505 set_predecessor(node, -1); // no predecessor (yet)
507 int successor_id = remote_find_successor(node, known_id, node->id);
508 if (successor_id == -1) {
509 INFO0("Cannot join the ring.");
512 set_finger(node, 0, successor_id);
513 print_finger_table(node);
516 return successor_id != -1;
520 * \brief Makes the current node quit the system
521 * \param node the current node
523 static void leave(node_t node)
525 DEBUG0("Well Guys! I Think it's time for me to quit ;)");
526 quit_notify(node, 1); // notify to my successor ( >>> 1 );
527 quit_notify(node, -1); // notify my predecessor ( >>> -1);
532 * \brief Notifies the successor or the predecessor of the current node
534 * \param node the current node
535 * \param to 1 to notify the successor, -1 to notify the predecessor
536 * FIXME: notify both nodes with only one call
538 static void quit_notify(node_t node, int to)
541 task_data_t req_data = xbt_new0(s_task_data_t, 1);
542 req_data->request_id = node->id;
543 req_data->successor_id = node->fingers[0].id;
544 req_data->pred_id = node->pred_id;
545 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
546 req_data->answer_to = NULL;
547 const char* task_name = NULL;
548 const char* to_mailbox = NULL;
549 if (to == 1) { // notify my successor
550 to_mailbox = node->fingers[0].mailbox;
551 INFO2("Telling my Successor %d about my departure via mailbox %s",
552 node->fingers[0].id, to_mailbox);
553 req_data->type = TASK_PREDECESSOR_LEAVING;
555 else if (to == -1) { // notify my predecessor
557 if (node->pred_id == -1) {
561 to_mailbox = node->pred_mailbox;
562 INFO2("Telling my Predecessor %d about my departure via mailbox %s",
563 node->pred_id, to_mailbox);
564 req_data->type = TASK_SUCCESSOR_LEAVING;
566 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
567 //char* mailbox = get_mailbox(to_mailbox);
568 msg_comm_t comm = MSG_task_isend(task, to_mailbox);
569 xbt_dynar_push(node->comms, &comm);
574 * \brief Makes the current node find the successor node of an id.
575 * \param node the current node
576 * \param id the id to find
577 * \return the id of the successor node, or -1 if the request failed
579 static int find_successor(node_t node, int id)
581 // is my successor the successor?
582 if (is_in_interval(id, node->id + 1, node->fingers[0].id)) {
583 return node->fingers[0].id;
586 // otherwise, ask the closest preceding finger in my table
587 int closest = closest_preceding_node(node, id);
588 return remote_find_successor(node, closest, id);
592 * \brief Asks another node the successor node of an id.
593 * \param node the current node
594 * \param ask_to the node to ask to
595 * \param id the id to find
596 * \return the id of the successor node, or -1 if the request failed
598 static int remote_find_successor(node_t node, int ask_to, int id)
602 char mailbox[MAILBOX_NAME_SIZE];
603 get_mailbox(ask_to, mailbox);
604 task_data_t req_data = xbt_new0(s_task_data_t, 1);
605 req_data->type = TASK_FIND_SUCCESSOR;
606 req_data->request_id = id;
607 get_mailbox(node->id, req_data->answer_to);
608 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
610 // send a "Find Successor" request to ask_to_id
611 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
612 DEBUG3("Sending a 'Find Successor' request (task %p) to %d for id %d", task_sent, ask_to, id);
613 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
616 DEBUG3("Failed to send the 'Find Successor' request (task %p) to %d for id %d",
617 task_sent, ask_to, id);
618 MSG_task_destroy(task_sent);
619 task_data_destroy(req_data);
623 // receive the answer
624 DEBUG3("Sent a 'Find Successor' request (task %p) to %d for key %d, waiting for the answer",
625 task_sent, ask_to, id);
628 if (node->comm_receive == NULL) {
629 m_task_t task_received = NULL;
630 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
633 res = MSG_comm_wait(node->comm_receive, timeout);
636 DEBUG2("Failed to receive the answer to my 'Find Successor' request (task %p): %d",
639 MSG_comm_destroy(node->comm_receive);
640 node->comm_receive = NULL;
643 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
644 DEBUG1("Received a task (%p)", task_received);
645 task_data_t ans_data = MSG_task_get_data(task_received);
648 MC_assert(task_received == task_sent);
651 if (task_received != task_sent) {
652 // this is not the expected answer
653 MSG_comm_destroy(node->comm_receive);
654 node->comm_receive = NULL;
655 handle_task(node, task_received);
658 // this is our answer
659 DEBUG4("Received the answer to my 'Find Successor' request for id %d (task %p): the successor of key %d is %d",
660 ans_data->request_id, task_received, id, ans_data->answer_id);
661 successor = ans_data->answer_id;
663 MSG_comm_destroy(node->comm_receive);
664 node->comm_receive = NULL;
665 MSG_task_destroy(task_received);
666 task_data_destroy(req_data);
676 * \brief Asks another node its predecessor.
677 * \param node the current node
678 * \param ask_to the node to ask to
679 * \return the id of its predecessor node, or -1 if the request failed
680 * (or if the node does not know its predecessor)
682 static int remote_get_predecessor(node_t node, int ask_to)
684 int predecessor_id = -1;
686 char mailbox[MAILBOX_NAME_SIZE];
687 get_mailbox(ask_to, mailbox);
688 task_data_t req_data = xbt_new0(s_task_data_t, 1);
689 req_data->type = TASK_GET_PREDECESSOR;
690 get_mailbox(node->id, req_data->answer_to);
691 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
693 // send a "Get Predecessor" request to ask_to_id
694 DEBUG1("Sending a 'Get Predecessor' request to %d", ask_to);
695 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
696 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
699 DEBUG2("Failed to send the 'Get Predecessor' request (task %p) to %d",
701 MSG_task_destroy(task_sent);
702 task_data_destroy(req_data);
706 // receive the answer
707 DEBUG3("Sent 'Get Predecessor' request (task %p) to %d, waiting for the answer on my mailbox '%s'",
708 task_sent, ask_to, req_data->answer_to);
711 if (node->comm_receive == NULL) { // FIXME simplify this
712 m_task_t task_received = NULL;
713 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
716 res = MSG_comm_wait(node->comm_receive, timeout);
719 DEBUG2("Failed to receive the answer to my 'Get Predecessor' request (task %p): %d",
722 MSG_comm_destroy(node->comm_receive);
723 node->comm_receive = NULL;
726 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
727 task_data_t ans_data = MSG_task_get_data(task_received);
730 MC_assert(task_received == task_sent);
733 if (task_received != task_sent) {
734 MSG_comm_destroy(node->comm_receive);
735 node->comm_receive = NULL;
736 handle_task(node, task_received);
739 DEBUG3("Received the answer to my 'Get Predecessor' request (task %p): the predecessor of node %d is %d",
740 task_received, ask_to, ans_data->answer_id);
741 predecessor_id = ans_data->answer_id;
743 MSG_comm_destroy(node->comm_receive);
744 node->comm_receive = NULL;
745 MSG_task_destroy(task_received);
746 task_data_destroy(req_data);
752 return predecessor_id;
756 * \brief Returns the closest preceding finger of an id
757 * with respect to the finger table of the current node.
758 * \param node the current node
759 * \param id the id to find
760 * \return the closest preceding finger of that id
762 int closest_preceding_node(node_t node, int id)
765 for (i = nb_bits - 1; i >= 0; i--) {
766 if (is_in_interval(node->fingers[i].id, node->id + 1, id - 1)) {
767 return node->fingers[i].id;
774 * \brief This function is called periodically. It checks the immediate
775 * successor of the current node.
776 * \param node the current node
778 static void stabilize(node_t node)
780 DEBUG0("Stabilizing node");
782 // get the predecessor of my immediate successor
784 int successor_id = node->fingers[0].id;
785 if (successor_id != node->id) {
786 candidate_id = remote_get_predecessor(node, successor_id);
789 candidate_id = node->pred_id;
792 // this node is a candidate to become my new successor
793 if (candidate_id != -1
794 && is_in_interval(candidate_id, node->id + 1, successor_id - 1)) {
795 set_finger(node, 0, candidate_id);
797 if (successor_id != node->id) {
798 remote_notify(node, successor_id, node->id);
803 * \brief Notifies the current node that its predecessor may have changed.
804 * \param node the current node
805 * \param candidate_id the possible new predecessor
807 static void notify(node_t node, int predecessor_candidate_id) {
809 if (node->pred_id == -1
810 || is_in_interval(predecessor_candidate_id, node->pred_id + 1, node->id - 1)) {
812 set_predecessor(node, predecessor_candidate_id);
813 print_finger_table(node);
816 DEBUG1("I don't have to change my predecessor to %d", predecessor_candidate_id);
821 * \brief Notifies a remote node that its predecessor may have changed.
822 * \param node the current node
823 * \param notify_id id of the node to notify
824 * \param candidate_id the possible new predecessor
826 static void remote_notify(node_t node, int notify_id, int predecessor_candidate_id) {
828 task_data_t req_data = xbt_new0(s_task_data_t, 1);
829 req_data->type = TASK_NOTIFY;
830 req_data->request_id = predecessor_candidate_id;
831 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
833 // send a "Notify" request to notify_id
834 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
835 DEBUG2("Sending a 'Notify' request (task %p) to %d", task, notify_id);
836 char mailbox[MAILBOX_NAME_SIZE];
837 get_mailbox(notify_id, mailbox);
838 msg_comm_t comm = MSG_task_isend(task, mailbox);
839 xbt_dynar_push(node->comms, &comm);
843 * \brief This function is called periodically.
844 * It refreshes the finger table of the current node.
845 * \param node the current node
847 static void fix_fingers(node_t node) {
849 DEBUG0("Fixing fingers");
850 int i = node->next_finger_to_fix;
851 int id = find_successor(node, node->id + powers2[i]);
854 if (id != node->fingers[i].id) {
855 set_finger(node, i, id);
856 print_finger_table(node);
858 node->next_finger_to_fix = (i + 1) % nb_bits;
863 * \brief This function is called periodically.
864 * It checks whether the predecessor has failed
865 * \param node the current node
867 static void check_predecessor(node_t node)
869 DEBUG0("Checking whether my predecessor is alive");
874 * \brief Performs a find successor request to a random id.
875 * \param node the current node
877 static void random_lookup(node_t node)
879 int id = 1337; // TODO pick a pseudorandom id
880 DEBUG1("Making a lookup request for id %d", id);
881 find_successor(node, id);
885 * \brief Main function.
887 int main(int argc, char *argv[])
890 printf("Usage: %s [-nb_bits=n] [-timeout=t] platform_file deployment_file\n", argv[0]);
891 printf("example: %s ../msg_platform.xml chord.xml\n", argv[0]);
895 MSG_global_init(&argc, argv);
897 char **options = &argv[1];
898 while (!strncmp(options[0], "-", 1)) {
900 int length = strlen("-nb_bits=");
901 if (!strncmp(options[0], "-nb_bits=", length) && strlen(options[0]) > length) {
902 nb_bits = atoi(options[0] + length);
903 DEBUG1("Set nb_bits to %d", nb_bits);
907 length = strlen("-timeout=");
908 if (!strncmp(options[0], "-timeout=", length) && strlen(options[0]) > length) {
909 timeout = atoi(options[0] + length);
910 DEBUG1("Set timeout to %d", timeout);
913 xbt_assert1(0, "Invalid chord option '%s'", options[0]);
919 const char* platform_file = options[0];
920 const char* application_file = options[1];
924 MSG_set_channel_number(0);
925 MSG_create_environment(platform_file);
927 MSG_function_register("node", node);
928 MSG_launch_application(application_file);
930 MSG_error_t res = MSG_main();
931 INFO1("Simulation time: %g", MSG_get_clock());