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 "simgrid/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 void chord_exit(void);
84 static int normalize(int id);
85 static int is_in_interval(int id, int start, int end);
86 static void get_mailbox(int host_id, char* mailbox);
87 static void task_free(void* task);
88 static void print_finger_table(node_t node);
89 static void set_finger(node_t node, int finger_index, int id);
90 static void set_predecessor(node_t node, int predecessor_id);
93 static int node(int argc, char *argv[]);
94 static void handle_task(node_t node, m_task_t task);
97 static void create(node_t node);
98 static int join(node_t node, int known_id);
99 static void leave(node_t node);
100 static int find_successor(node_t node, int id);
101 static int remote_find_successor(node_t node, int ask_to_id, int id);
102 static int remote_get_predecessor(node_t node, int ask_to_id);
103 static int closest_preceding_node(node_t node, int id);
104 static void stabilize(node_t node);
105 static void notify(node_t node, int predecessor_candidate_id);
106 static void remote_notify(node_t node, int notify_to, int predecessor_candidate_id);
107 static void fix_fingers(node_t node);
108 static void check_predecessor(node_t node);
109 static void random_lookup(node_t);
110 static void quit_notify(node_t node, int to);
113 * \brief Global initialization of the Chord simulation.
115 static void chord_initialize(void)
117 // compute the powers of 2 once for all
118 powers2 = xbt_new(int, nb_bits);
121 for (i = 0; i < nb_bits; i++) {
126 XBT_DEBUG("Sets nb_keys to %d", nb_keys);
129 static void chord_exit(void)
135 * \brief Turns an id into an equivalent id in [0, nb_keys).
137 * \return the corresponding normalized id
139 static int normalize(int id)
141 // like id % nb_keys, but works with negatives numbers (and faster)
142 return id & (nb_keys - 1);
146 * \brief Returns whether an id belongs to the interval [start, end].
148 * The parameters are noramlized to make sure they are between 0 and nb_keys - 1).
149 * 1 belongs to [62, 3]
150 * 1 does not belong to [3, 62]
151 * 63 belongs to [62, 3]
152 * 63 does not belong to [3, 62]
153 * 24 belongs to [21, 29]
154 * 24 does not belong to [29, 21]
156 * \param id id to check
157 * \param start lower bound
158 * \param end upper bound
159 * \return a non-zero value if id in in [start, end]
161 static int is_in_interval(int id, int start, int end)
164 start = normalize(start);
165 end = normalize(end);
167 // make sure end >= start and id >= start
180 * \brief Gets the mailbox name of a host given its chord id.
181 * \param node_id id of a node
182 * \param mailbox pointer to where the mailbox name should be written
183 * (there must be enough space)
185 static void get_mailbox(int node_id, char* mailbox)
187 snprintf(mailbox, MAILBOX_NAME_SIZE - 1, "%d", node_id);
191 * \brief Frees the memory used by a task.
192 * \param task the MSG task to destroy
194 static void task_free(void* task)
196 // TODO add a parameter data_free_function to MSG_task_create?
197 xbt_free(MSG_task_get_data(task));
198 MSG_task_destroy(task);
202 * \brief Displays the finger table of a node.
205 static void print_finger_table(node_t node)
207 if (XBT_LOG_ISENABLED(msg_chord, xbt_log_priority_verbose)) {
209 XBT_VERB("My finger table:");
210 XBT_VERB("Start | Succ ");
211 for (i = 0; i < nb_bits; i++) {
212 XBT_VERB(" %3d | %3d ", (node->id + powers2[i]) % nb_keys, node->fingers[i].id);
214 XBT_VERB("Predecessor: %d", node->pred_id);
219 * \brief Sets a finger of the current node.
220 * \param node the current node
221 * \param finger_index index of the finger to set (0 to nb_bits - 1)
222 * \param id the id to set for this finger
224 static void set_finger(node_t node, int finger_index, int id)
226 if (id != node->fingers[finger_index].id) {
227 node->fingers[finger_index].id = id;
228 get_mailbox(id, node->fingers[finger_index].mailbox);
229 node->last_change_date = MSG_get_clock();
230 XBT_DEBUG("My new finger #%d is %d", finger_index, id);
235 * \brief Sets the predecessor of the current node.
236 * \param node the current node
237 * \param id the id to predecessor, or -1 to unset the predecessor
239 static void set_predecessor(node_t node, int predecessor_id)
241 if (predecessor_id != node->pred_id) {
242 node->pred_id = predecessor_id;
244 if (predecessor_id != -1) {
245 get_mailbox(predecessor_id, node->pred_mailbox);
247 node->last_change_date = MSG_get_clock();
249 XBT_DEBUG("My new predecessor is %d", predecessor_id);
254 * \brief Node Function
257 * - the id of a guy I know in the system (except for the first node)
258 * - the time to sleep before I join (except for the first node)
260 int node(int argc, char *argv[])
262 /* Reduce the run size for the MC */
264 periodic_stabilize_delay = 8;
265 periodic_fix_fingers_delay = 8;
266 periodic_check_predecessor_delay = 8;
269 double init_time = MSG_get_clock();
270 m_task_t task_received = NULL;
272 int join_success = 0;
274 double next_stabilize_date = init_time + periodic_stabilize_delay;
275 double next_fix_fingers_date = init_time + periodic_fix_fingers_delay;
276 double next_check_predecessor_date = init_time + periodic_check_predecessor_delay;
277 double next_lookup_date = init_time + periodic_lookup_delay;
279 xbt_assert(argc == 3 || argc == 5, "Wrong number of arguments for this node");
281 // initialize my node
283 node.id = atoi(argv[1]);
284 get_mailbox(node.id, node.mailbox);
285 node.next_finger_to_fix = 0;
286 node.fingers = xbt_new0(s_finger_t, nb_bits);
287 node.last_change_date = init_time;
289 for (i = 0; i < nb_bits; i++) {
290 node.fingers[i].id = -1;
291 set_finger(&node, i, node.id);
294 if (argc == 3) { // first ring
295 deadline = atof(argv[2]);
300 int known_id = atoi(argv[2]);
301 //double sleep_time = atof(argv[3]);
302 deadline = atof(argv[4]);
305 // sleep before starting
306 XBT_DEBUG("Let's sleep during %f", sleep_time);
307 MSG_process_sleep(sleep_time);
309 XBT_DEBUG("Hey! Let's join the system.");
311 join_success = join(&node, known_id);
315 while (MSG_get_clock() < init_time + deadline
316 // && MSG_get_clock() < node.last_change_date + 1000
317 && MSG_get_clock() < max_simulation_time) {
319 if (node.comm_receive == NULL) {
320 task_received = NULL;
321 node.comm_receive = MSG_task_irecv(&task_received, node.mailbox);
322 // FIXME: do not make MSG_task_irecv() calls from several functions
325 if (!MSG_comm_test(node.comm_receive)) {
327 // no task was received: make some periodic calls
328 if (MSG_get_clock() >= next_stabilize_date) {
330 next_stabilize_date = MSG_get_clock() + periodic_stabilize_delay;
332 else if (MSG_get_clock() >= next_fix_fingers_date) {
334 next_fix_fingers_date = MSG_get_clock() + periodic_fix_fingers_delay;
336 else if (MSG_get_clock() >= next_check_predecessor_date) {
337 check_predecessor(&node);
338 next_check_predecessor_date = MSG_get_clock() + periodic_check_predecessor_delay;
340 else if (MSG_get_clock() >= next_lookup_date) {
341 random_lookup(&node);
342 next_lookup_date = MSG_get_clock() + periodic_lookup_delay;
345 // nothing to do: sleep for a while
346 MSG_process_sleep(5);
350 if (node.comm_receive && MSG_comm_test(node.comm_receive)) {
352 // a transfer has occured
354 MSG_error_t status = MSG_comm_get_status(node.comm_receive);
356 if (status != MSG_OK) {
357 XBT_DEBUG("Failed to receive a task. Nevermind.");
358 MSG_comm_destroy(node.comm_receive);
359 node.comm_receive = NULL;
362 // the task was successfully received
363 MSG_comm_destroy(node.comm_receive);
364 node.comm_receive = NULL;
365 handle_task(&node, task_received);
370 if (node.comm_receive) {
371 MSG_comm_destroy(node.comm_receive);
372 node.comm_receive = NULL;
379 // stop the simulation
380 xbt_free(node.fingers);
385 * \brief This function is called when the current node receives a task.
386 * \param node the current node
387 * \param task the task to handle (don't touch it then:
388 * it will be destroyed, reused or forwarded)
390 static void handle_task(node_t node, m_task_t task) {
392 XBT_DEBUG("Handling task %p", task);
393 char mailbox[MAILBOX_NAME_SIZE];
394 task_data_t task_data = (task_data_t) MSG_task_get_data(task);
395 e_task_type_t type = task_data->type;
399 case TASK_FIND_SUCCESSOR:
400 XBT_DEBUG("Receiving a 'Find Successor' request from %s for id %d",
401 task_data->issuer_host_name, task_data->request_id);
402 // is my successor the successor?
403 if (is_in_interval(task_data->request_id, node->id + 1, node->fingers[0].id)) {
404 task_data->type = TASK_FIND_SUCCESSOR_ANSWER;
405 task_data->answer_id = node->fingers[0].id;
406 XBT_DEBUG("Sending back a 'Find Successor Answer' to %s (mailbox %s): the successor of %d is %d",
407 task_data->issuer_host_name,
408 task_data->answer_to,
409 task_data->request_id, task_data->answer_id);
410 MSG_task_dsend(task, task_data->answer_to, task_free);
413 // otherwise, forward the request to the closest preceding finger in my table
414 int closest = closest_preceding_node(node, task_data->request_id);
415 XBT_DEBUG("Forwarding the 'Find Successor' request for id %d to my closest preceding finger %d",
416 task_data->request_id, closest);
417 get_mailbox(closest, mailbox);
418 MSG_task_dsend(task, mailbox, task_free);
422 case TASK_GET_PREDECESSOR:
423 XBT_DEBUG("Receiving a 'Get Predecessor' request from %s", task_data->issuer_host_name);
424 task_data->type = TASK_GET_PREDECESSOR_ANSWER;
425 task_data->answer_id = node->pred_id;
426 XBT_DEBUG("Sending back a 'Get Predecessor Answer' to %s via mailbox '%s': my predecessor is %d",
427 task_data->issuer_host_name,
428 task_data->answer_to, task_data->answer_id);
429 MSG_task_dsend(task, task_data->answer_to, task_free);
433 // someone is telling me that he may be my new predecessor
434 XBT_DEBUG("Receiving a 'Notify' request from %s", task_data->issuer_host_name);
435 notify(node, task_data->request_id);
439 case TASK_PREDECESSOR_LEAVING:
440 // my predecessor is about to quit
441 XBT_DEBUG("Receiving a 'Predecessor Leaving' message from %s", task_data->issuer_host_name);
442 // modify my predecessor
443 set_predecessor(node, task_data->request_id);
446 >> notify my new predecessor
447 >> send a notify_predecessors !!
451 case TASK_SUCCESSOR_LEAVING:
452 // my successor is about to quit
453 XBT_DEBUG("Receiving a 'Successor Leaving' message from %s", task_data->issuer_host_name);
454 // modify my successor FIXME : this should be implicit ?
455 set_finger(node, 0, task_data->request_id);
458 >> notify my new successor
459 >> update my table & predecessors table */
462 case TASK_FIND_SUCCESSOR_ANSWER:
463 case TASK_GET_PREDECESSOR_ANSWER:
464 XBT_DEBUG("Ignoring unexpected task of type %d (%p)", (int)type, task);
471 * \brief Initializes the current node as the first one of the system.
472 * \param node the current node
474 static void create(node_t node)
476 XBT_DEBUG("Create a new Chord ring...");
477 set_predecessor(node, -1); // -1 means that I have no predecessor
478 print_finger_table(node);
482 * \brief Makes the current node join the ring, knowing the id of a node
483 * already in the ring
484 * \param node the current node
485 * \param known_id id of a node already in the ring
486 * \return 1 if the join operation succeeded, 0 otherwise
488 static int join(node_t node, int known_id)
490 XBT_INFO("Joining the ring with id %d, knowing node %d", node->id, known_id);
491 set_predecessor(node, -1); // no predecessor (yet)
495 for (i = 0; i < nb_bits; i++) {
496 set_finger(node, i, known_id);
500 int successor_id = remote_find_successor(node, known_id, node->id);
501 if (successor_id == -1) {
502 XBT_INFO("Cannot join the ring.");
505 set_finger(node, 0, successor_id);
506 print_finger_table(node);
509 return successor_id != -1;
513 * \brief Makes the current node quit the system
514 * \param node the current node
516 static void leave(node_t node)
518 XBT_DEBUG("Well Guys! I Think it's time for me to quit ;)");
519 quit_notify(node, 1); // notify to my successor ( >>> 1 );
520 quit_notify(node, -1); // notify my predecessor ( >>> -1);
525 * \brief Notifies the successor or the predecessor of the current node
527 * \param node the current node
528 * \param to 1 to notify the successor, -1 to notify the predecessor
529 * FIXME: notify both nodes with only one call
531 static void quit_notify(node_t node, int to)
534 task_data_t req_data = xbt_new0(s_task_data_t, 1);
535 req_data->request_id = node->id;
536 req_data->successor_id = node->fingers[0].id;
537 req_data->pred_id = node->pred_id;
538 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
539 req_data->answer_to = NULL;
540 const char* task_name = NULL;
541 const char* to_mailbox = NULL;
542 if (to == 1) { // notify my successor
543 to_mailbox = node->fingers[0].mailbox;
544 XBT_INFO("Telling my Successor %d about my departure via mailbox %s",
545 node->fingers[0].id, to_mailbox);
546 req_data->type = TASK_PREDECESSOR_LEAVING;
548 else if (to == -1) { // notify my predecessor
550 if (node->pred_id == -1) {
554 to_mailbox = node->pred_mailbox;
555 XBT_INFO("Telling my Predecessor %d about my departure via mailbox %s",
556 node->pred_id, to_mailbox);
557 req_data->type = TASK_SUCCESSOR_LEAVING;
559 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
560 //char* mailbox = get_mailbox(to_mailbox);
561 msg_comm_t comm = MSG_task_isend(task, to_mailbox);
562 xbt_dynar_push(node->comms, &comm);
567 * \brief Makes the current node find the successor node of an id.
568 * \param node the current node
569 * \param id the id to find
570 * \return the id of the successor node, or -1 if the request failed
572 static int find_successor(node_t node, int id)
574 // is my successor the successor?
575 if (is_in_interval(id, node->id + 1, node->fingers[0].id)) {
576 return node->fingers[0].id;
579 // otherwise, ask the closest preceding finger in my table
580 int closest = closest_preceding_node(node, id);
581 return remote_find_successor(node, closest, id);
585 * \brief Asks another node the successor node of an id.
586 * \param node the current node
587 * \param ask_to the node to ask to
588 * \param id the id to find
589 * \return the id of the successor node, or -1 if the request failed
591 static int remote_find_successor(node_t node, int ask_to, int id)
595 char mailbox[MAILBOX_NAME_SIZE];
596 get_mailbox(ask_to, mailbox);
597 task_data_t req_data = xbt_new0(s_task_data_t, 1);
598 req_data->type = TASK_FIND_SUCCESSOR;
599 req_data->request_id = id;
600 get_mailbox(node->id, req_data->answer_to);
601 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
603 // send a "Find Successor" request to ask_to_id
604 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
605 XBT_DEBUG("Sending a 'Find Successor' request (task %p) to %d for id %d", task_sent, ask_to, id);
606 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
609 XBT_DEBUG("Failed to send the 'Find Successor' request (task %p) to %d for id %d",
610 task_sent, ask_to, id);
611 task_free(task_sent);
615 // receive the answer
616 XBT_DEBUG("Sent a 'Find Successor' request (task %p) to %d for key %d, waiting for the answer",
617 task_sent, ask_to, id);
620 if (node->comm_receive == NULL) {
621 m_task_t task_received = NULL;
622 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
625 res = MSG_comm_wait(node->comm_receive, timeout);
628 XBT_DEBUG("Failed to receive the answer to my 'Find Successor' request (task %p): %d",
629 task_sent, (int)res);
631 MSG_comm_destroy(node->comm_receive);
632 node->comm_receive = NULL;
635 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
636 XBT_DEBUG("Received a task (%p)", task_received);
637 task_data_t ans_data = MSG_task_get_data(task_received);
640 MC_assert(task_received == task_sent);
643 if (task_received != task_sent) {
644 // this is not the expected answer
645 MSG_comm_destroy(node->comm_receive);
646 node->comm_receive = NULL;
647 handle_task(node, task_received);
650 // this is our answer
651 XBT_DEBUG("Received the answer to my 'Find Successor' request for id %d (task %p): the successor of key %d is %d",
652 ans_data->request_id, task_received, id, ans_data->answer_id);
653 successor = ans_data->answer_id;
655 MSG_comm_destroy(node->comm_receive);
656 node->comm_receive = NULL;
657 task_free(task_received);
667 * \brief Asks another node its predecessor.
668 * \param node the current node
669 * \param ask_to the node to ask to
670 * \return the id of its predecessor node, or -1 if the request failed
671 * (or if the node does not know its predecessor)
673 static int remote_get_predecessor(node_t node, int ask_to)
675 int predecessor_id = -1;
677 char mailbox[MAILBOX_NAME_SIZE];
678 get_mailbox(ask_to, mailbox);
679 task_data_t req_data = xbt_new0(s_task_data_t, 1);
680 req_data->type = TASK_GET_PREDECESSOR;
681 get_mailbox(node->id, req_data->answer_to);
682 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
684 // send a "Get Predecessor" request to ask_to_id
685 XBT_DEBUG("Sending a 'Get Predecessor' request to %d", ask_to);
686 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
687 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
690 XBT_DEBUG("Failed to send the 'Get Predecessor' request (task %p) to %d",
692 task_free(task_sent);
696 // receive the answer
697 XBT_DEBUG("Sent 'Get Predecessor' request (task %p) to %d, waiting for the answer on my mailbox '%s'",
698 task_sent, ask_to, req_data->answer_to);
701 if (node->comm_receive == NULL) { // FIXME simplify this
702 m_task_t task_received = NULL;
703 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
706 res = MSG_comm_wait(node->comm_receive, timeout);
709 XBT_DEBUG("Failed to receive the answer to my 'Get Predecessor' request (task %p): %d",
710 task_sent, (int)res);
712 MSG_comm_destroy(node->comm_receive);
713 node->comm_receive = NULL;
716 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
717 task_data_t ans_data = MSG_task_get_data(task_received);
720 MC_assert(task_received == task_sent);
723 if (task_received != task_sent) {
724 MSG_comm_destroy(node->comm_receive);
725 node->comm_receive = NULL;
726 handle_task(node, task_received);
729 XBT_DEBUG("Received the answer to my 'Get Predecessor' request (task %p): the predecessor of node %d is %d",
730 task_received, ask_to, ans_data->answer_id);
731 predecessor_id = ans_data->answer_id;
733 MSG_comm_destroy(node->comm_receive);
734 node->comm_receive = NULL;
735 task_free(task_received);
741 return predecessor_id;
745 * \brief Returns the closest preceding finger of an id
746 * with respect to the finger table of the current node.
747 * \param node the current node
748 * \param id the id to find
749 * \return the closest preceding finger of that id
751 int closest_preceding_node(node_t node, int id)
754 for (i = nb_bits - 1; i >= 0; i--) {
755 if (is_in_interval(node->fingers[i].id, node->id + 1, id - 1)) {
756 return node->fingers[i].id;
763 * \brief This function is called periodically. It checks the immediate
764 * successor of the current node.
765 * \param node the current node
767 static void stabilize(node_t node)
769 XBT_DEBUG("Stabilizing node");
771 // get the predecessor of my immediate successor
773 int successor_id = node->fingers[0].id;
774 if (successor_id != node->id) {
775 candidate_id = remote_get_predecessor(node, successor_id);
778 candidate_id = node->pred_id;
781 // this node is a candidate to become my new successor
782 if (candidate_id != -1
783 && is_in_interval(candidate_id, node->id + 1, successor_id - 1)) {
784 set_finger(node, 0, candidate_id);
786 if (successor_id != node->id) {
787 remote_notify(node, successor_id, node->id);
792 * \brief Notifies the current node that its predecessor may have changed.
793 * \param node the current node
794 * \param candidate_id the possible new predecessor
796 static void notify(node_t node, int predecessor_candidate_id) {
798 if (node->pred_id == -1
799 || is_in_interval(predecessor_candidate_id, node->pred_id + 1, node->id - 1)) {
801 set_predecessor(node, predecessor_candidate_id);
802 print_finger_table(node);
805 XBT_DEBUG("I don't have to change my predecessor to %d", predecessor_candidate_id);
810 * \brief Notifies a remote node that its predecessor may have changed.
811 * \param node the current node
812 * \param notify_id id of the node to notify
813 * \param candidate_id the possible new predecessor
815 static void remote_notify(node_t node, int notify_id, int predecessor_candidate_id) {
817 task_data_t req_data = xbt_new0(s_task_data_t, 1);
818 req_data->type = TASK_NOTIFY;
819 req_data->request_id = predecessor_candidate_id;
820 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
822 // send a "Notify" request to notify_id
823 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
824 XBT_DEBUG("Sending a 'Notify' request (task %p) to %d", task, notify_id);
825 char mailbox[MAILBOX_NAME_SIZE];
826 get_mailbox(notify_id, mailbox);
827 MSG_task_dsend(task, mailbox, task_free);
831 * \brief This function is called periodically.
832 * It refreshes the finger table of the current node.
833 * \param node the current node
835 static void fix_fingers(node_t node) {
837 XBT_DEBUG("Fixing fingers");
838 int i = node->next_finger_to_fix;
839 int id = find_successor(node, node->id + powers2[i]);
842 if (id != node->fingers[i].id) {
843 set_finger(node, i, id);
844 print_finger_table(node);
846 node->next_finger_to_fix = (i + 1) % nb_bits;
851 * \brief This function is called periodically.
852 * It checks whether the predecessor has failed
853 * \param node the current node
855 static void check_predecessor(node_t node)
857 XBT_DEBUG("Checking whether my predecessor is alive");
862 * \brief Performs a find successor request to a random id.
863 * \param node the current node
865 static void random_lookup(node_t node)
867 int id = 1337; // TODO pick a pseudorandom id
868 XBT_DEBUG("Making a lookup request for id %d", id);
869 find_successor(node, id);
873 * \brief Main function.
875 int main(int argc, char *argv[])
877 MSG_global_init(&argc, argv);
879 printf("Usage: %s [-nb_bits=n] [-timeout=t] platform_file deployment_file\n", argv[0]);
880 printf("example: %s ../msg_platform.xml chord.xml\n", argv[0]);
884 char **options = &argv[1];
885 while (!strncmp(options[0], "-", 1)) {
887 int length = strlen("-nb_bits=");
888 if (!strncmp(options[0], "-nb_bits=", length) && strlen(options[0]) > length) {
889 nb_bits = atoi(options[0] + length);
890 XBT_DEBUG("Set nb_bits to %d", nb_bits);
894 length = strlen("-timeout=");
895 if (!strncmp(options[0], "-timeout=", length) && strlen(options[0]) > length) {
896 timeout = atoi(options[0] + length);
897 XBT_DEBUG("Set timeout to %d", timeout);
900 xbt_die("Invalid chord option '%s'", options[0]);
906 const char* platform_file = options[0];
907 const char* application_file = options[1];
911 MSG_create_environment(platform_file);
913 MSG_function_register("node", node);
914 MSG_launch_application(application_file);
916 MSG_error_t res = MSG_main();
917 XBT_CRITICAL("Messages created: %ld", smx_total_comms);
918 XBT_INFO("Simulated time: %g", MSG_get_clock());