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 /** @addtogroup MSG_examples
16 * - <b>chord/chord.c: Classical Chord P2P protocol</b>
17 * This example implements the well known Chord P2P protocol. Its
18 * main advantage is that it constitute a fully working non-trivial
19 * example. In addition, its implementation is rather efficient, as
20 * demonstrated in http://hal.inria.fr/inria-00602216/
24 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_chord,
25 "Messages specific for this msg example");
29 #define MAILBOX_NAME_SIZE 10
31 static int nb_bits = 24;
32 static int nb_keys = 0;
33 static int timeout = 50;
34 static int max_simulation_time = 1000;
35 static int periodic_stabilize_delay = 20;
36 static int periodic_fix_fingers_delay = 120;
37 static int periodic_check_predecessor_delay = 120;
38 static int periodic_lookup_delay = 10;
40 extern long int smx_total_comms;
45 typedef struct s_finger {
47 char mailbox[MAILBOX_NAME_SIZE]; // string representation of the id
48 } s_finger_t, *finger_t;
53 typedef struct s_node {
55 char mailbox[MAILBOX_NAME_SIZE]; // my mailbox name (string representation of the id)
56 s_finger_t *fingers; // finger table, of size nb_bits (fingers[0] is my successor)
57 int pred_id; // predecessor id
58 char pred_mailbox[MAILBOX_NAME_SIZE]; // predecessor's mailbox name
59 int next_finger_to_fix; // index of the next finger to fix in fix_fingers()
60 msg_comm_t comm_receive; // current communication to receive
61 double last_change_date; // last time I changed a finger or my predecessor
65 * Types of tasks exchanged between nodes.
69 TASK_FIND_SUCCESSOR_ANSWER,
71 TASK_GET_PREDECESSOR_ANSWER,
73 TASK_SUCCESSOR_LEAVING,
74 TASK_PREDECESSOR_LEAVING
78 * Data attached with the tasks sent and received
80 typedef struct s_task_data {
81 e_task_type_t type; // type of task
82 int request_id; // id paramater (used by some types of tasks)
83 int request_finger; // finger parameter (used by some types of tasks)
84 int answer_id; // answer (used by some types of tasks)
85 char answer_to[MAILBOX_NAME_SIZE]; // mailbox to send an answer to (if any)
86 const char* issuer_host_name; // used for logging
87 } s_task_data_t, *task_data_t;
92 static void chord_initialize(void);
93 static void chord_exit(void);
94 static int normalize(int id);
95 static int is_in_interval(int id, int start, int end);
96 static void get_mailbox(int host_id, char* mailbox);
97 static void task_free(void* task);
98 static void print_finger_table(node_t node);
99 static void set_finger(node_t node, int finger_index, int id);
100 static void set_predecessor(node_t node, int predecessor_id);
103 static int node(int argc, char *argv[]);
104 static void handle_task(node_t node, m_task_t task);
107 static void create(node_t node);
108 static int join(node_t node, int known_id);
109 static void leave(node_t node);
110 static int find_successor(node_t node, int id);
111 static int remote_find_successor(node_t node, int ask_to_id, int id);
112 static int remote_get_predecessor(node_t node, int ask_to_id);
113 static int closest_preceding_node(node_t node, int id);
114 static void stabilize(node_t node);
115 static void notify(node_t node, int predecessor_candidate_id);
116 static void remote_notify(node_t node, int notify_to, int predecessor_candidate_id);
117 static void fix_fingers(node_t node);
118 static void check_predecessor(node_t node);
119 static void random_lookup(node_t);
120 static void quit_notify(node_t node, int to);
123 * \brief Global initialization of the Chord simulation.
125 static void chord_initialize(void)
127 // compute the powers of 2 once for all
128 powers2 = xbt_new(int, nb_bits);
131 for (i = 0; i < nb_bits; i++) {
136 XBT_DEBUG("Sets nb_keys to %d", nb_keys);
139 static void chord_exit(void)
145 * \brief Turns an id into an equivalent id in [0, nb_keys).
147 * \return the corresponding normalized id
149 static int normalize(int id)
151 // like id % nb_keys, but works with negatives numbers (and faster)
152 return id & (nb_keys - 1);
156 * \brief Returns whether an id belongs to the interval [start, end].
158 * The parameters are noramlized to make sure they are between 0 and nb_keys - 1).
159 * 1 belongs to [62, 3]
160 * 1 does not belong to [3, 62]
161 * 63 belongs to [62, 3]
162 * 63 does not belong to [3, 62]
163 * 24 belongs to [21, 29]
164 * 24 does not belong to [29, 21]
166 * \param id id to check
167 * \param start lower bound
168 * \param end upper bound
169 * \return a non-zero value if id in in [start, end]
171 static int is_in_interval(int id, int start, int end)
174 start = normalize(start);
175 end = normalize(end);
177 // make sure end >= start and id >= start
190 * \brief Gets the mailbox name of a host given its chord id.
191 * \param node_id id of a node
192 * \param mailbox pointer to where the mailbox name should be written
193 * (there must be enough space)
195 static void get_mailbox(int node_id, char* mailbox)
197 snprintf(mailbox, MAILBOX_NAME_SIZE - 1, "%d", node_id);
201 * \brief Frees the memory used by a task.
202 * \param task the MSG task to destroy
204 static void task_free(void* task)
206 // TODO add a parameter data_free_function to MSG_task_create?
207 xbt_free(MSG_task_get_data(task));
208 MSG_task_destroy(task);
212 * \brief Displays the finger table of a node.
215 static void print_finger_table(node_t node)
217 if (XBT_LOG_ISENABLED(msg_chord, xbt_log_priority_verbose)) {
219 XBT_VERB("My finger table:");
220 XBT_VERB("Start | Succ ");
221 for (i = 0; i < nb_bits; i++) {
222 XBT_VERB(" %3d | %3d ", (node->id + powers2[i]) % nb_keys, node->fingers[i].id);
224 XBT_VERB("Predecessor: %d", node->pred_id);
229 * \brief Sets a finger of the current node.
230 * \param node the current node
231 * \param finger_index index of the finger to set (0 to nb_bits - 1)
232 * \param id the id to set for this finger
234 static void set_finger(node_t node, int finger_index, int id)
236 if (id != node->fingers[finger_index].id) {
237 node->fingers[finger_index].id = id;
238 get_mailbox(id, node->fingers[finger_index].mailbox);
239 node->last_change_date = MSG_get_clock();
240 XBT_DEBUG("My new finger #%d is %d", finger_index, id);
245 * \brief Sets the predecessor of the current node.
246 * \param node the current node
247 * \param id the id to predecessor, or -1 to unset the predecessor
249 static void set_predecessor(node_t node, int predecessor_id)
251 if (predecessor_id != node->pred_id) {
252 node->pred_id = predecessor_id;
254 if (predecessor_id != -1) {
255 get_mailbox(predecessor_id, node->pred_mailbox);
257 node->last_change_date = MSG_get_clock();
259 XBT_DEBUG("My new predecessor is %d", predecessor_id);
264 * \brief Node Function
267 * - the id of a guy I know in the system (except for the first node)
268 * - the time to sleep before I join (except for the first node)
270 int node(int argc, char *argv[])
272 /* Reduce the run size for the MC */
274 periodic_stabilize_delay = 8;
275 periodic_fix_fingers_delay = 8;
276 periodic_check_predecessor_delay = 8;
279 double init_time = MSG_get_clock();
280 m_task_t task_received = NULL;
282 int join_success = 0;
284 double next_stabilize_date = init_time + periodic_stabilize_delay;
285 double next_fix_fingers_date = init_time + periodic_fix_fingers_delay;
286 double next_check_predecessor_date = init_time + periodic_check_predecessor_delay;
287 double next_lookup_date = init_time + periodic_lookup_delay;
289 xbt_assert(argc == 3 || argc == 5, "Wrong number of arguments for this node");
291 // initialize my node
293 node.id = atoi(argv[1]);
294 get_mailbox(node.id, node.mailbox);
295 node.next_finger_to_fix = 0;
296 node.fingers = xbt_new0(s_finger_t, nb_bits);
297 node.last_change_date = init_time;
299 for (i = 0; i < nb_bits; i++) {
300 node.fingers[i].id = -1;
301 set_finger(&node, i, node.id);
304 if (argc == 3) { // first ring
305 deadline = atof(argv[2]);
310 int known_id = atoi(argv[2]);
311 //double sleep_time = atof(argv[3]);
312 deadline = atof(argv[4]);
315 // sleep before starting
316 XBT_DEBUG("Let's sleep during %f", sleep_time);
317 MSG_process_sleep(sleep_time);
319 XBT_DEBUG("Hey! Let's join the system.");
321 join_success = join(&node, known_id);
325 while (MSG_get_clock() < init_time + deadline
326 // && MSG_get_clock() < node.last_change_date + 1000
327 && MSG_get_clock() < max_simulation_time) {
329 if (node.comm_receive == NULL) {
330 task_received = NULL;
331 node.comm_receive = MSG_task_irecv(&task_received, node.mailbox);
332 // FIXME: do not make MSG_task_irecv() calls from several functions
335 if (!MSG_comm_test(node.comm_receive)) {
337 // no task was received: make some periodic calls
338 if (MSG_get_clock() >= next_stabilize_date) {
340 next_stabilize_date = MSG_get_clock() + periodic_stabilize_delay;
342 else if (MSG_get_clock() >= next_fix_fingers_date) {
344 next_fix_fingers_date = MSG_get_clock() + periodic_fix_fingers_delay;
346 else if (MSG_get_clock() >= next_check_predecessor_date) {
347 check_predecessor(&node);
348 next_check_predecessor_date = MSG_get_clock() + periodic_check_predecessor_delay;
350 else if (MSG_get_clock() >= next_lookup_date) {
351 random_lookup(&node);
352 next_lookup_date = MSG_get_clock() + periodic_lookup_delay;
355 // nothing to do: sleep for a while
356 MSG_process_sleep(5);
360 if (node.comm_receive && MSG_comm_test(node.comm_receive)) {
362 // a transfer has occured
364 MSG_error_t status = MSG_comm_get_status(node.comm_receive);
366 if (status != MSG_OK) {
367 XBT_DEBUG("Failed to receive a task. Nevermind.");
368 MSG_comm_destroy(node.comm_receive);
369 node.comm_receive = NULL;
372 // the task was successfully received
373 MSG_comm_destroy(node.comm_receive);
374 node.comm_receive = NULL;
375 handle_task(&node, task_received);
380 if (node.comm_receive) {
381 MSG_comm_destroy(node.comm_receive);
382 node.comm_receive = NULL;
389 // stop the simulation
390 xbt_free(node.fingers);
395 * \brief This function is called when the current node receives a task.
396 * \param node the current node
397 * \param task the task to handle (don't touch it then:
398 * it will be destroyed, reused or forwarded)
400 static void handle_task(node_t node, m_task_t task) {
402 XBT_DEBUG("Handling task %p", task);
403 char mailbox[MAILBOX_NAME_SIZE];
404 task_data_t task_data = (task_data_t) MSG_task_get_data(task);
405 e_task_type_t type = task_data->type;
409 case TASK_FIND_SUCCESSOR:
410 XBT_DEBUG("Receiving a 'Find Successor' request from %s for id %d",
411 task_data->issuer_host_name, task_data->request_id);
412 // is my successor the successor?
413 if (is_in_interval(task_data->request_id, node->id + 1, node->fingers[0].id)) {
414 task_data->type = TASK_FIND_SUCCESSOR_ANSWER;
415 task_data->answer_id = node->fingers[0].id;
416 XBT_DEBUG("Sending back a 'Find Successor Answer' to %s (mailbox %s): the successor of %d is %d",
417 task_data->issuer_host_name,
418 task_data->answer_to,
419 task_data->request_id, task_data->answer_id);
420 MSG_task_dsend(task, task_data->answer_to, task_free);
423 // otherwise, forward the request to the closest preceding finger in my table
424 int closest = closest_preceding_node(node, task_data->request_id);
425 XBT_DEBUG("Forwarding the 'Find Successor' request for id %d to my closest preceding finger %d",
426 task_data->request_id, closest);
427 get_mailbox(closest, mailbox);
428 MSG_task_dsend(task, mailbox, task_free);
432 case TASK_GET_PREDECESSOR:
433 XBT_DEBUG("Receiving a 'Get Predecessor' request from %s", task_data->issuer_host_name);
434 task_data->type = TASK_GET_PREDECESSOR_ANSWER;
435 task_data->answer_id = node->pred_id;
436 XBT_DEBUG("Sending back a 'Get Predecessor Answer' to %s via mailbox '%s': my predecessor is %d",
437 task_data->issuer_host_name,
438 task_data->answer_to, task_data->answer_id);
439 MSG_task_dsend(task, task_data->answer_to, task_free);
443 // someone is telling me that he may be my new predecessor
444 XBT_DEBUG("Receiving a 'Notify' request from %s", task_data->issuer_host_name);
445 notify(node, task_data->request_id);
449 case TASK_PREDECESSOR_LEAVING:
450 // my predecessor is about to quit
451 XBT_DEBUG("Receiving a 'Predecessor Leaving' message from %s", task_data->issuer_host_name);
452 // modify my predecessor
453 set_predecessor(node, task_data->request_id);
456 >> notify my new predecessor
457 >> send a notify_predecessors !!
461 case TASK_SUCCESSOR_LEAVING:
462 // my successor is about to quit
463 XBT_DEBUG("Receiving a 'Successor Leaving' message from %s", task_data->issuer_host_name);
464 // modify my successor FIXME : this should be implicit ?
465 set_finger(node, 0, task_data->request_id);
468 >> notify my new successor
469 >> update my table & predecessors table */
472 case TASK_FIND_SUCCESSOR_ANSWER:
473 case TASK_GET_PREDECESSOR_ANSWER:
474 XBT_DEBUG("Ignoring unexpected task of type %d (%p)", (int)type, task);
481 * \brief Initializes the current node as the first one of the system.
482 * \param node the current node
484 static void create(node_t node)
486 XBT_DEBUG("Create a new Chord ring...");
487 set_predecessor(node, -1); // -1 means that I have no predecessor
488 print_finger_table(node);
492 * \brief Makes the current node join the ring, knowing the id of a node
493 * already in the ring
494 * \param node the current node
495 * \param known_id id of a node already in the ring
496 * \return 1 if the join operation succeeded, 0 otherwise
498 static int join(node_t node, int known_id)
500 XBT_INFO("Joining the ring with id %d, knowing node %d", node->id, known_id);
501 set_predecessor(node, -1); // no predecessor (yet)
505 for (i = 0; i < nb_bits; i++) {
506 set_finger(node, i, known_id);
510 int successor_id = remote_find_successor(node, known_id, node->id);
511 if (successor_id == -1) {
512 XBT_INFO("Cannot join the ring.");
515 set_finger(node, 0, successor_id);
516 print_finger_table(node);
519 return successor_id != -1;
523 * \brief Makes the current node quit the system
524 * \param node the current node
526 static void leave(node_t node)
528 XBT_DEBUG("Well Guys! I Think it's time for me to quit ;)");
529 quit_notify(node, 1); // notify to my successor ( >>> 1 );
530 quit_notify(node, -1); // notify my predecessor ( >>> -1);
535 * \brief Notifies the successor or the predecessor of the current node
537 * \param node the current node
538 * \param to 1 to notify the successor, -1 to notify the predecessor
539 * FIXME: notify both nodes with only one call
541 static void quit_notify(node_t node, int to)
544 task_data_t req_data = xbt_new0(s_task_data_t, 1);
545 req_data->request_id = node->id;
546 req_data->successor_id = node->fingers[0].id;
547 req_data->pred_id = node->pred_id;
548 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
549 req_data->answer_to = NULL;
550 const char* task_name = NULL;
551 const char* to_mailbox = NULL;
552 if (to == 1) { // notify my successor
553 to_mailbox = node->fingers[0].mailbox;
554 XBT_INFO("Telling my Successor %d about my departure via mailbox %s",
555 node->fingers[0].id, to_mailbox);
556 req_data->type = TASK_PREDECESSOR_LEAVING;
558 else if (to == -1) { // notify my predecessor
560 if (node->pred_id == -1) {
564 to_mailbox = node->pred_mailbox;
565 XBT_INFO("Telling my Predecessor %d about my departure via mailbox %s",
566 node->pred_id, to_mailbox);
567 req_data->type = TASK_SUCCESSOR_LEAVING;
569 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
570 //char* mailbox = get_mailbox(to_mailbox);
571 msg_comm_t comm = MSG_task_isend(task, to_mailbox);
572 xbt_dynar_push(node->comms, &comm);
577 * \brief Makes the current node find the successor node of an id.
578 * \param node the current node
579 * \param id the id to find
580 * \return the id of the successor node, or -1 if the request failed
582 static int find_successor(node_t node, int id)
584 // is my successor the successor?
585 if (is_in_interval(id, node->id + 1, node->fingers[0].id)) {
586 return node->fingers[0].id;
589 // otherwise, ask the closest preceding finger in my table
590 int closest = closest_preceding_node(node, id);
591 return remote_find_successor(node, closest, id);
595 * \brief Asks another node the successor node of an id.
596 * \param node the current node
597 * \param ask_to the node to ask to
598 * \param id the id to find
599 * \return the id of the successor node, or -1 if the request failed
601 static int remote_find_successor(node_t node, int ask_to, int id)
605 char mailbox[MAILBOX_NAME_SIZE];
606 get_mailbox(ask_to, mailbox);
607 task_data_t req_data = xbt_new0(s_task_data_t, 1);
608 req_data->type = TASK_FIND_SUCCESSOR;
609 req_data->request_id = id;
610 get_mailbox(node->id, req_data->answer_to);
611 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
613 // send a "Find Successor" request to ask_to_id
614 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
615 XBT_DEBUG("Sending a 'Find Successor' request (task %p) to %d for id %d", task_sent, ask_to, id);
616 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
619 XBT_DEBUG("Failed to send the 'Find Successor' request (task %p) to %d for id %d",
620 task_sent, ask_to, id);
621 task_free(task_sent);
625 // receive the answer
626 XBT_DEBUG("Sent a 'Find Successor' request (task %p) to %d for key %d, waiting for the answer",
627 task_sent, ask_to, id);
630 if (node->comm_receive == NULL) {
631 m_task_t task_received = NULL;
632 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
635 res = MSG_comm_wait(node->comm_receive, timeout);
638 XBT_DEBUG("Failed to receive the answer to my 'Find Successor' request (task %p): %d",
639 task_sent, (int)res);
641 MSG_comm_destroy(node->comm_receive);
642 node->comm_receive = NULL;
645 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
646 XBT_DEBUG("Received a task (%p)", task_received);
647 task_data_t ans_data = MSG_task_get_data(task_received);
650 MC_assert(task_received == task_sent);
653 if (task_received != task_sent) {
654 // this is not the expected answer
655 MSG_comm_destroy(node->comm_receive);
656 node->comm_receive = NULL;
657 handle_task(node, task_received);
660 // this is our answer
661 XBT_DEBUG("Received the answer to my 'Find Successor' request for id %d (task %p): the successor of key %d is %d",
662 ans_data->request_id, task_received, id, ans_data->answer_id);
663 successor = ans_data->answer_id;
665 MSG_comm_destroy(node->comm_receive);
666 node->comm_receive = NULL;
667 task_free(task_received);
677 * \brief Asks another node its predecessor.
678 * \param node the current node
679 * \param ask_to the node to ask to
680 * \return the id of its predecessor node, or -1 if the request failed
681 * (or if the node does not know its predecessor)
683 static int remote_get_predecessor(node_t node, int ask_to)
685 int predecessor_id = -1;
687 char mailbox[MAILBOX_NAME_SIZE];
688 get_mailbox(ask_to, mailbox);
689 task_data_t req_data = xbt_new0(s_task_data_t, 1);
690 req_data->type = TASK_GET_PREDECESSOR;
691 get_mailbox(node->id, req_data->answer_to);
692 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
694 // send a "Get Predecessor" request to ask_to_id
695 XBT_DEBUG("Sending a 'Get Predecessor' request to %d", ask_to);
696 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
697 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
700 XBT_DEBUG("Failed to send the 'Get Predecessor' request (task %p) to %d",
702 task_free(task_sent);
706 // receive the answer
707 XBT_DEBUG("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 XBT_DEBUG("Failed to receive the answer to my 'Get Predecessor' request (task %p): %d",
720 task_sent, (int)res);
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 XBT_DEBUG("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 task_free(task_received);
751 return predecessor_id;
755 * \brief Returns the closest preceding finger of an id
756 * with respect to the finger table of the current node.
757 * \param node the current node
758 * \param id the id to find
759 * \return the closest preceding finger of that id
761 int closest_preceding_node(node_t node, int id)
764 for (i = nb_bits - 1; i >= 0; i--) {
765 if (is_in_interval(node->fingers[i].id, node->id + 1, id - 1)) {
766 return node->fingers[i].id;
773 * \brief This function is called periodically. It checks the immediate
774 * successor of the current node.
775 * \param node the current node
777 static void stabilize(node_t node)
779 XBT_DEBUG("Stabilizing node");
781 // get the predecessor of my immediate successor
783 int successor_id = node->fingers[0].id;
784 if (successor_id != node->id) {
785 candidate_id = remote_get_predecessor(node, successor_id);
788 candidate_id = node->pred_id;
791 // this node is a candidate to become my new successor
792 if (candidate_id != -1
793 && is_in_interval(candidate_id, node->id + 1, successor_id - 1)) {
794 set_finger(node, 0, candidate_id);
796 if (successor_id != node->id) {
797 remote_notify(node, successor_id, node->id);
802 * \brief Notifies the current node that its predecessor may have changed.
803 * \param node the current node
804 * \param candidate_id the possible new predecessor
806 static void notify(node_t node, int predecessor_candidate_id) {
808 if (node->pred_id == -1
809 || is_in_interval(predecessor_candidate_id, node->pred_id + 1, node->id - 1)) {
811 set_predecessor(node, predecessor_candidate_id);
812 print_finger_table(node);
815 XBT_DEBUG("I don't have to change my predecessor to %d", predecessor_candidate_id);
820 * \brief Notifies a remote node that its predecessor may have changed.
821 * \param node the current node
822 * \param notify_id id of the node to notify
823 * \param candidate_id the possible new predecessor
825 static void remote_notify(node_t node, int notify_id, int predecessor_candidate_id) {
827 task_data_t req_data = xbt_new0(s_task_data_t, 1);
828 req_data->type = TASK_NOTIFY;
829 req_data->request_id = predecessor_candidate_id;
830 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
832 // send a "Notify" request to notify_id
833 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
834 XBT_DEBUG("Sending a 'Notify' request (task %p) to %d", task, notify_id);
835 char mailbox[MAILBOX_NAME_SIZE];
836 get_mailbox(notify_id, mailbox);
837 MSG_task_dsend(task, mailbox, task_free);
841 * \brief This function is called periodically.
842 * It refreshes the finger table of the current node.
843 * \param node the current node
845 static void fix_fingers(node_t node) {
847 XBT_DEBUG("Fixing fingers");
848 int i = node->next_finger_to_fix;
849 int id = find_successor(node, node->id + powers2[i]);
852 if (id != node->fingers[i].id) {
853 set_finger(node, i, id);
854 print_finger_table(node);
856 node->next_finger_to_fix = (i + 1) % nb_bits;
861 * \brief This function is called periodically.
862 * It checks whether the predecessor has failed
863 * \param node the current node
865 static void check_predecessor(node_t node)
867 XBT_DEBUG("Checking whether my predecessor is alive");
872 * \brief Performs a find successor request to a random id.
873 * \param node the current node
875 static void random_lookup(node_t node)
877 int id = 1337; // TODO pick a pseudorandom id
878 XBT_DEBUG("Making a lookup request for id %d", id);
879 find_successor(node, id);
883 * \brief Main function.
885 int main(int argc, char *argv[])
887 MSG_init(&argc, argv);
889 printf("Usage: %s [-nb_bits=n] [-timeout=t] platform_file deployment_file\n", argv[0]);
890 printf("example: %s ../msg_platform.xml chord.xml\n", argv[0]);
894 char **options = &argv[1];
895 while (!strncmp(options[0], "-", 1)) {
897 int length = strlen("-nb_bits=");
898 if (!strncmp(options[0], "-nb_bits=", length) && strlen(options[0]) > length) {
899 nb_bits = atoi(options[0] + length);
900 XBT_DEBUG("Set nb_bits to %d", nb_bits);
904 length = strlen("-timeout=");
905 if (!strncmp(options[0], "-timeout=", length) && strlen(options[0]) > length) {
906 timeout = atoi(options[0] + length);
907 XBT_DEBUG("Set timeout to %d", timeout);
910 xbt_die("Invalid chord option '%s'", options[0]);
916 const char* platform_file = options[0];
917 const char* application_file = options[1];
921 MSG_create_environment(platform_file);
923 MSG_function_register("node", node);
924 MSG_launch_application(application_file);
926 MSG_error_t res = MSG_main();
927 XBT_CRITICAL("Messages created: %ld", smx_total_comms);
928 XBT_INFO("Simulated time: %g", MSG_get_clock());