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 #include "xbt/xbt_os_time.h"
16 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_chord,
17 "Messages specific for this msg example");
21 #define MAILBOX_NAME_SIZE 10
23 static int nb_bits = 24;
24 static int nb_keys = 0;
25 static int timeout = 50;
26 static int max_simulation_time = 1000;
27 static int periodic_stabilize_delay = 20;
28 static int periodic_fix_fingers_delay = 120;
29 static int periodic_check_predecessor_delay = 120;
30 static int periodic_lookup_delay = 10;
32 extern long int smx_total_comms;
37 typedef struct finger {
39 char mailbox[MAILBOX_NAME_SIZE]; // string representation of the id
40 } s_finger_t, *finger_t;
47 char mailbox[MAILBOX_NAME_SIZE]; // my mailbox name (string representation of the id)
48 s_finger_t *fingers; // finger table, of size nb_bits (fingers[0] is my successor)
49 int pred_id; // predecessor id
50 char pred_mailbox[MAILBOX_NAME_SIZE]; // predecessor's mailbox name
51 int next_finger_to_fix; // index of the next finger to fix in fix_fingers()
52 msg_comm_t comm_receive; // current communication to receive
53 double last_change_date; // last time I changed a finger or my predecessor
57 * Types of tasks exchanged between nodes.
61 TASK_FIND_SUCCESSOR_ANSWER,
63 TASK_GET_PREDECESSOR_ANSWER,
65 TASK_SUCCESSOR_LEAVING,
66 TASK_PREDECESSOR_LEAVING
70 * Data attached with the tasks sent and received
72 typedef struct task_data {
73 e_task_type_t type; // type of task
74 int request_id; // id paramater (used by some types of tasks)
75 int request_finger; // finger parameter (used by some types of tasks)
76 int answer_id; // answer (used by some types of tasks)
77 char answer_to[MAILBOX_NAME_SIZE]; // mailbox to send an answer to (if any)
78 const char* issuer_host_name; // used for logging
79 } s_task_data_t, *task_data_t;
84 static void chord_initialize(void);
85 static void chord_exit(void);
86 static int normalize(int id);
87 static int is_in_interval(int id, int start, int end);
88 static void get_mailbox(int host_id, char* mailbox);
89 static void task_free(void* task);
90 static void print_finger_table(node_t node);
91 static void set_finger(node_t node, int finger_index, int id);
92 static void set_predecessor(node_t node, int predecessor_id);
95 static int node(int argc, char *argv[]);
96 static void handle_task(node_t node, m_task_t task);
99 static void create(node_t node);
100 static int join(node_t node, int known_id);
101 static void leave(node_t node);
102 static int find_successor(node_t node, int id);
103 static int remote_find_successor(node_t node, int ask_to_id, int id);
104 static int remote_get_predecessor(node_t node, int ask_to_id);
105 static int closest_preceding_node(node_t node, int id);
106 static void stabilize(node_t node);
107 static void notify(node_t node, int predecessor_candidate_id);
108 static void remote_notify(node_t node, int notify_to, int predecessor_candidate_id);
109 static void fix_fingers(node_t node);
110 static void check_predecessor(node_t node);
111 static void random_lookup(node_t);
112 static void quit_notify(node_t node, int to);
115 * \brief Global initialization of the Chord simulation.
117 static void chord_initialize(void)
119 // compute the powers of 2 once for all
120 powers2 = xbt_new(int, nb_bits);
123 for (i = 0; i < nb_bits; i++) {
128 XBT_DEBUG("Sets nb_keys to %d", nb_keys);
131 static void chord_exit(void)
137 * \brief Turns an id into an equivalent id in [0, nb_keys).
139 * \return the corresponding normalized id
141 static int normalize(int id)
143 // like id % nb_keys, but works with negatives numbers (and faster)
144 return id & (nb_keys - 1);
148 * \brief Returns whether an id belongs to the interval [start, end].
150 * The parameters are noramlized to make sure they are between 0 and nb_keys - 1).
151 * 1 belongs to [62, 3]
152 * 1 does not belong to [3, 62]
153 * 63 belongs to [62, 3]
154 * 63 does not belong to [3, 62]
155 * 24 belongs to [21, 29]
156 * 24 does not belong to [29, 21]
158 * \param id id to check
159 * \param start lower bound
160 * \param end upper bound
161 * \return a non-zero value if id in in [start, end]
163 static int is_in_interval(int id, int start, int end)
166 start = normalize(start);
167 end = normalize(end);
169 // make sure end >= start and id >= start
182 * \brief Gets the mailbox name of a host given its chord id.
183 * \param node_id id of a node
184 * \param mailbox pointer to where the mailbox name should be written
185 * (there must be enough space)
187 static void get_mailbox(int node_id, char* mailbox)
189 snprintf(mailbox, MAILBOX_NAME_SIZE - 1, "%d", node_id);
193 * \brief Frees the memory used by a task.
194 * \param task the MSG task to destroy
196 static void task_free(void* task)
198 // TODO add a parameter data_free_function to MSG_task_create?
199 xbt_free(MSG_task_get_data(task));
200 MSG_task_destroy(task);
204 * \brief Displays the finger table of a node.
207 static void print_finger_table(node_t node)
209 if (XBT_LOG_ISENABLED(msg_chord, xbt_log_priority_verbose)) {
211 XBT_VERB("My finger table:");
212 XBT_VERB("Start | Succ ");
213 for (i = 0; i < nb_bits; i++) {
214 XBT_VERB(" %3d | %3d ", (node->id + powers2[i]) % nb_keys, node->fingers[i].id);
216 XBT_VERB("Predecessor: %d", node->pred_id);
221 * \brief Sets a finger of the current node.
222 * \param node the current node
223 * \param finger_index index of the finger to set (0 to nb_bits - 1)
224 * \param id the id to set for this finger
226 static void set_finger(node_t node, int finger_index, int id)
228 if (id != node->fingers[finger_index].id) {
229 node->fingers[finger_index].id = id;
230 get_mailbox(id, node->fingers[finger_index].mailbox);
231 node->last_change_date = MSG_get_clock();
232 XBT_DEBUG("My new finger #%d is %d", finger_index, id);
237 * \brief Sets the predecessor of the current node.
238 * \param node the current node
239 * \param id the id to predecessor, or -1 to unset the predecessor
241 static void set_predecessor(node_t node, int predecessor_id)
243 if (predecessor_id != node->pred_id) {
244 node->pred_id = predecessor_id;
246 if (predecessor_id != -1) {
247 get_mailbox(predecessor_id, node->pred_mailbox);
249 node->last_change_date = MSG_get_clock();
251 XBT_DEBUG("My new predecessor is %d", predecessor_id);
256 * \brief Node Function
259 * - the id of a guy I know in the system (except for the first node)
260 * - the time to sleep before I join (except for the first node)
262 int node(int argc, char *argv[])
264 /* Reduce the run size for the MC */
266 periodic_stabilize_delay = 8;
267 periodic_fix_fingers_delay = 8;
268 periodic_check_predecessor_delay = 8;
271 double init_time = MSG_get_clock();
272 m_task_t task_received = NULL;
274 int join_success = 0;
276 double next_stabilize_date = init_time + periodic_stabilize_delay;
277 double next_fix_fingers_date = init_time + periodic_fix_fingers_delay;
278 double next_check_predecessor_date = init_time + periodic_check_predecessor_delay;
279 double next_lookup_date = init_time + periodic_lookup_delay;
281 xbt_assert(argc == 3 || argc == 5, "Wrong number of arguments for this node");
283 // initialize my node
285 node.id = atoi(argv[1]);
286 get_mailbox(node.id, node.mailbox);
287 node.next_finger_to_fix = 0;
288 node.fingers = xbt_new0(s_finger_t, nb_bits);
289 node.last_change_date = init_time;
291 for (i = 0; i < nb_bits; i++) {
292 node.fingers[i].id = -1;
293 set_finger(&node, i, node.id);
296 if (argc == 3) { // first ring
297 deadline = atof(argv[2]);
302 int known_id = atoi(argv[2]);
303 //double sleep_time = atof(argv[3]);
304 deadline = atof(argv[4]);
307 // sleep before starting
308 XBT_DEBUG("Let's sleep during %f", sleep_time);
309 MSG_process_sleep(sleep_time);
311 XBT_DEBUG("Hey! Let's join the system.");
313 join_success = join(&node, known_id);
317 while (MSG_get_clock() < init_time + deadline
318 // && MSG_get_clock() < node.last_change_date + 1000
319 && MSG_get_clock() < max_simulation_time) {
321 if (node.comm_receive == NULL) {
322 task_received = NULL;
323 node.comm_receive = MSG_task_irecv(&task_received, node.mailbox);
324 // FIXME: do not make MSG_task_irecv() calls from several functions
327 if (!MSG_comm_test(node.comm_receive)) {
329 // no task was received: make some periodic calls
330 if (MSG_get_clock() >= next_stabilize_date) {
332 next_stabilize_date = MSG_get_clock() + periodic_stabilize_delay;
334 else if (MSG_get_clock() >= next_fix_fingers_date) {
336 next_fix_fingers_date = MSG_get_clock() + periodic_fix_fingers_delay;
338 else if (MSG_get_clock() >= next_check_predecessor_date) {
339 check_predecessor(&node);
340 next_check_predecessor_date = MSG_get_clock() + periodic_check_predecessor_delay;
342 else if (MSG_get_clock() >= next_lookup_date) {
343 random_lookup(&node);
344 next_lookup_date = MSG_get_clock() + periodic_lookup_delay;
347 // nothing to do: sleep for a while
348 MSG_process_sleep(5);
352 if (node.comm_receive && MSG_comm_test(node.comm_receive)) {
354 // a transfer has occured
356 MSG_error_t status = MSG_comm_get_status(node.comm_receive);
358 if (status != MSG_OK) {
359 XBT_DEBUG("Failed to receive a task. Nevermind.");
360 MSG_comm_destroy(node.comm_receive);
361 node.comm_receive = NULL;
364 // the task was successfully received
365 MSG_comm_destroy(node.comm_receive);
366 node.comm_receive = NULL;
367 handle_task(&node, task_received);
372 if (node.comm_receive) {
373 MSG_comm_destroy(node.comm_receive);
374 node.comm_receive = NULL;
381 // stop the simulation
382 xbt_free(node.fingers);
387 * \brief This function is called when the current node receives a task.
388 * \param node the current node
389 * \param task the task to handle (don't touch it then:
390 * it will be destroyed, reused or forwarded)
392 static void handle_task(node_t node, m_task_t task) {
394 XBT_DEBUG("Handling task %p", task);
395 char mailbox[MAILBOX_NAME_SIZE];
396 task_data_t task_data = (task_data_t) MSG_task_get_data(task);
397 e_task_type_t type = task_data->type;
401 case TASK_FIND_SUCCESSOR:
402 XBT_DEBUG("Receiving a 'Find Successor' request from %s for id %d",
403 task_data->issuer_host_name, task_data->request_id);
404 // is my successor the successor?
405 if (is_in_interval(task_data->request_id, node->id + 1, node->fingers[0].id)) {
406 task_data->type = TASK_FIND_SUCCESSOR_ANSWER;
407 task_data->answer_id = node->fingers[0].id;
408 XBT_DEBUG("Sending back a 'Find Successor Answer' to %s (mailbox %s): the successor of %d is %d",
409 task_data->issuer_host_name,
410 task_data->answer_to,
411 task_data->request_id, task_data->answer_id);
412 MSG_task_dsend(task, task_data->answer_to, task_free);
415 // otherwise, forward the request to the closest preceding finger in my table
416 int closest = closest_preceding_node(node, task_data->request_id);
417 XBT_DEBUG("Forwarding the 'Find Successor' request for id %d to my closest preceding finger %d",
418 task_data->request_id, closest);
419 get_mailbox(closest, mailbox);
420 MSG_task_dsend(task, mailbox, task_free);
424 case TASK_GET_PREDECESSOR:
425 XBT_DEBUG("Receiving a 'Get Predecessor' request from %s", task_data->issuer_host_name);
426 task_data->type = TASK_GET_PREDECESSOR_ANSWER;
427 task_data->answer_id = node->pred_id;
428 XBT_DEBUG("Sending back a 'Get Predecessor Answer' to %s via mailbox '%s': my predecessor is %d",
429 task_data->issuer_host_name,
430 task_data->answer_to, task_data->answer_id);
431 MSG_task_dsend(task, task_data->answer_to, task_free);
435 // someone is telling me that he may be my new predecessor
436 XBT_DEBUG("Receiving a 'Notify' request from %s", task_data->issuer_host_name);
437 notify(node, task_data->request_id);
441 case TASK_PREDECESSOR_LEAVING:
442 // my predecessor is about to quit
443 XBT_DEBUG("Receiving a 'Predecessor Leaving' message from %s", task_data->issuer_host_name);
444 // modify my predecessor
445 set_predecessor(node, task_data->request_id);
448 >> notify my new predecessor
449 >> send a notify_predecessors !!
453 case TASK_SUCCESSOR_LEAVING:
454 // my successor is about to quit
455 XBT_DEBUG("Receiving a 'Successor Leaving' message from %s", task_data->issuer_host_name);
456 // modify my successor FIXME : this should be implicit ?
457 set_finger(node, 0, task_data->request_id);
460 >> notify my new successor
461 >> update my table & predecessors table */
464 case TASK_FIND_SUCCESSOR_ANSWER:
465 case TASK_GET_PREDECESSOR_ANSWER:
466 XBT_DEBUG("Ignoring unexpected task of type %d (%p)", type, task);
473 * \brief Initializes the current node as the first one of the system.
474 * \param node the current node
476 static void create(node_t node)
478 XBT_DEBUG("Create a new Chord ring...");
479 set_predecessor(node, -1); // -1 means that I have no predecessor
480 print_finger_table(node);
484 * \brief Makes the current node join the ring, knowing the id of a node
485 * already in the ring
486 * \param node the current node
487 * \param known_id id of a node already in the ring
488 * \return 1 if the join operation succeeded, 0 otherwise
490 static int join(node_t node, int known_id)
492 XBT_INFO("Joining the ring with id %d, knowing node %d", node->id, known_id);
493 set_predecessor(node, -1); // no predecessor (yet)
497 for (i = 0; i < nb_bits; i++) {
498 set_finger(node, i, known_id);
502 int successor_id = remote_find_successor(node, known_id, node->id);
503 if (successor_id == -1) {
504 XBT_INFO("Cannot join the ring.");
507 set_finger(node, 0, successor_id);
508 print_finger_table(node);
511 return successor_id != -1;
515 * \brief Makes the current node quit the system
516 * \param node the current node
518 static void leave(node_t node)
520 XBT_DEBUG("Well Guys! I Think it's time for me to quit ;)");
521 quit_notify(node, 1); // notify to my successor ( >>> 1 );
522 quit_notify(node, -1); // notify my predecessor ( >>> -1);
527 * \brief Notifies the successor or the predecessor of the current node
529 * \param node the current node
530 * \param to 1 to notify the successor, -1 to notify the predecessor
531 * FIXME: notify both nodes with only one call
533 static void quit_notify(node_t node, int to)
536 task_data_t req_data = xbt_new0(s_task_data_t, 1);
537 req_data->request_id = node->id;
538 req_data->successor_id = node->fingers[0].id;
539 req_data->pred_id = node->pred_id;
540 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
541 req_data->answer_to = NULL;
542 const char* task_name = NULL;
543 const char* to_mailbox = NULL;
544 if (to == 1) { // notify my successor
545 to_mailbox = node->fingers[0].mailbox;
546 XBT_INFO("Telling my Successor %d about my departure via mailbox %s",
547 node->fingers[0].id, to_mailbox);
548 req_data->type = TASK_PREDECESSOR_LEAVING;
550 else if (to == -1) { // notify my predecessor
552 if (node->pred_id == -1) {
556 to_mailbox = node->pred_mailbox;
557 XBT_INFO("Telling my Predecessor %d about my departure via mailbox %s",
558 node->pred_id, to_mailbox);
559 req_data->type = TASK_SUCCESSOR_LEAVING;
561 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
562 //char* mailbox = get_mailbox(to_mailbox);
563 msg_comm_t comm = MSG_task_isend(task, to_mailbox);
564 xbt_dynar_push(node->comms, &comm);
569 * \brief Makes the current node find the successor node of an id.
570 * \param node the current node
571 * \param id the id to find
572 * \return the id of the successor node, or -1 if the request failed
574 static int find_successor(node_t node, int id)
576 // is my successor the successor?
577 if (is_in_interval(id, node->id + 1, node->fingers[0].id)) {
578 return node->fingers[0].id;
581 // otherwise, ask the closest preceding finger in my table
582 int closest = closest_preceding_node(node, id);
583 return remote_find_successor(node, closest, id);
587 * \brief Asks another node the successor node of an id.
588 * \param node the current node
589 * \param ask_to the node to ask to
590 * \param id the id to find
591 * \return the id of the successor node, or -1 if the request failed
593 static int remote_find_successor(node_t node, int ask_to, int id)
597 char mailbox[MAILBOX_NAME_SIZE];
598 get_mailbox(ask_to, mailbox);
599 task_data_t req_data = xbt_new0(s_task_data_t, 1);
600 req_data->type = TASK_FIND_SUCCESSOR;
601 req_data->request_id = id;
602 get_mailbox(node->id, req_data->answer_to);
603 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
605 // send a "Find Successor" request to ask_to_id
606 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
607 XBT_DEBUG("Sending a 'Find Successor' request (task %p) to %d for id %d", task_sent, ask_to, id);
608 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
611 XBT_DEBUG("Failed to send the 'Find Successor' request (task %p) to %d for id %d",
612 task_sent, ask_to, id);
613 task_free(task_sent);
617 // receive the answer
618 XBT_DEBUG("Sent a 'Find Successor' request (task %p) to %d for key %d, waiting for the answer",
619 task_sent, ask_to, id);
622 if (node->comm_receive == NULL) {
623 m_task_t task_received = NULL;
624 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
627 res = MSG_comm_wait(node->comm_receive, timeout);
630 XBT_DEBUG("Failed to receive the answer to my 'Find Successor' request (task %p): %d",
633 MSG_comm_destroy(node->comm_receive);
634 node->comm_receive = NULL;
637 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
638 XBT_DEBUG("Received a task (%p)", task_received);
639 task_data_t ans_data = MSG_task_get_data(task_received);
642 MC_assert(task_received == task_sent);
645 if (task_received != task_sent) {
646 // this is not the expected answer
647 MSG_comm_destroy(node->comm_receive);
648 node->comm_receive = NULL;
649 handle_task(node, task_received);
652 // this is our answer
653 XBT_DEBUG("Received the answer to my 'Find Successor' request for id %d (task %p): the successor of key %d is %d",
654 ans_data->request_id, task_received, id, ans_data->answer_id);
655 successor = ans_data->answer_id;
657 MSG_comm_destroy(node->comm_receive);
658 node->comm_receive = NULL;
659 task_free(task_received);
669 * \brief Asks another node its predecessor.
670 * \param node the current node
671 * \param ask_to the node to ask to
672 * \return the id of its predecessor node, or -1 if the request failed
673 * (or if the node does not know its predecessor)
675 static int remote_get_predecessor(node_t node, int ask_to)
677 int predecessor_id = -1;
679 char mailbox[MAILBOX_NAME_SIZE];
680 get_mailbox(ask_to, mailbox);
681 task_data_t req_data = xbt_new0(s_task_data_t, 1);
682 req_data->type = TASK_GET_PREDECESSOR;
683 get_mailbox(node->id, req_data->answer_to);
684 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
686 // send a "Get Predecessor" request to ask_to_id
687 XBT_DEBUG("Sending a 'Get Predecessor' request to %d", ask_to);
688 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
689 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
692 XBT_DEBUG("Failed to send the 'Get Predecessor' request (task %p) to %d",
694 task_free(task_sent);
698 // receive the answer
699 XBT_DEBUG("Sent 'Get Predecessor' request (task %p) to %d, waiting for the answer on my mailbox '%s'",
700 task_sent, ask_to, req_data->answer_to);
703 if (node->comm_receive == NULL) { // FIXME simplify this
704 m_task_t task_received = NULL;
705 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
708 res = MSG_comm_wait(node->comm_receive, timeout);
711 XBT_DEBUG("Failed to receive the answer to my 'Get Predecessor' request (task %p): %d",
714 MSG_comm_destroy(node->comm_receive);
715 node->comm_receive = NULL;
718 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
719 task_data_t ans_data = MSG_task_get_data(task_received);
722 MC_assert(task_received == task_sent);
725 if (task_received != task_sent) {
726 MSG_comm_destroy(node->comm_receive);
727 node->comm_receive = NULL;
728 handle_task(node, task_received);
731 XBT_DEBUG("Received the answer to my 'Get Predecessor' request (task %p): the predecessor of node %d is %d",
732 task_received, ask_to, ans_data->answer_id);
733 predecessor_id = ans_data->answer_id;
735 MSG_comm_destroy(node->comm_receive);
736 node->comm_receive = NULL;
737 task_free(task_received);
743 return predecessor_id;
747 * \brief Returns the closest preceding finger of an id
748 * with respect to the finger table of the current node.
749 * \param node the current node
750 * \param id the id to find
751 * \return the closest preceding finger of that id
753 int closest_preceding_node(node_t node, int id)
756 for (i = nb_bits - 1; i >= 0; i--) {
757 if (is_in_interval(node->fingers[i].id, node->id + 1, id - 1)) {
758 return node->fingers[i].id;
765 * \brief This function is called periodically. It checks the immediate
766 * successor of the current node.
767 * \param node the current node
769 static void stabilize(node_t node)
771 XBT_DEBUG("Stabilizing node");
773 // get the predecessor of my immediate successor
775 int successor_id = node->fingers[0].id;
776 if (successor_id != node->id) {
777 candidate_id = remote_get_predecessor(node, successor_id);
780 candidate_id = node->pred_id;
783 // this node is a candidate to become my new successor
784 if (candidate_id != -1
785 && is_in_interval(candidate_id, node->id + 1, successor_id - 1)) {
786 set_finger(node, 0, candidate_id);
788 if (successor_id != node->id) {
789 remote_notify(node, successor_id, node->id);
794 * \brief Notifies the current node that its predecessor may have changed.
795 * \param node the current node
796 * \param candidate_id the possible new predecessor
798 static void notify(node_t node, int predecessor_candidate_id) {
800 if (node->pred_id == -1
801 || is_in_interval(predecessor_candidate_id, node->pred_id + 1, node->id - 1)) {
803 set_predecessor(node, predecessor_candidate_id);
804 print_finger_table(node);
807 XBT_DEBUG("I don't have to change my predecessor to %d", predecessor_candidate_id);
812 * \brief Notifies a remote node that its predecessor may have changed.
813 * \param node the current node
814 * \param notify_id id of the node to notify
815 * \param candidate_id the possible new predecessor
817 static void remote_notify(node_t node, int notify_id, int predecessor_candidate_id) {
819 task_data_t req_data = xbt_new0(s_task_data_t, 1);
820 req_data->type = TASK_NOTIFY;
821 req_data->request_id = predecessor_candidate_id;
822 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
824 // send a "Notify" request to notify_id
825 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
826 XBT_DEBUG("Sending a 'Notify' request (task %p) to %d", task, notify_id);
827 char mailbox[MAILBOX_NAME_SIZE];
828 get_mailbox(notify_id, mailbox);
829 MSG_task_dsend(task, mailbox, task_free);
833 * \brief This function is called periodically.
834 * It refreshes the finger table of the current node.
835 * \param node the current node
837 static void fix_fingers(node_t node) {
839 XBT_DEBUG("Fixing fingers");
840 int i = node->next_finger_to_fix;
841 int id = find_successor(node, node->id + powers2[i]);
844 if (id != node->fingers[i].id) {
845 set_finger(node, i, id);
846 print_finger_table(node);
848 node->next_finger_to_fix = (i + 1) % nb_bits;
853 * \brief This function is called periodically.
854 * It checks whether the predecessor has failed
855 * \param node the current node
857 static void check_predecessor(node_t node)
859 XBT_DEBUG("Checking whether my predecessor is alive");
864 * \brief Performs a find successor request to a random id.
865 * \param node the current node
867 static void random_lookup(node_t node)
869 int id = 1337; // TODO pick a pseudorandom id
870 XBT_DEBUG("Making a lookup request for id %d", id);
871 find_successor(node, id);
875 * \brief Main function.
877 int main(int argc, char *argv[])
880 printf("Usage: %s [-nb_bits=n] [-timeout=t] platform_file deployment_file\n", argv[0]);
881 printf("example: %s ../msg_platform.xml chord.xml\n", argv[0]);
885 MSG_global_init(&argc, argv);
887 char **options = &argv[1];
888 while (!strncmp(options[0], "-", 1)) {
890 int length = strlen("-nb_bits=");
891 if (!strncmp(options[0], "-nb_bits=", length) && strlen(options[0]) > length) {
892 nb_bits = atoi(options[0] + length);
893 XBT_DEBUG("Set nb_bits to %d", nb_bits);
897 length = strlen("-timeout=");
898 if (!strncmp(options[0], "-timeout=", length) && strlen(options[0]) > length) {
899 timeout = atoi(options[0] + length);
900 XBT_DEBUG("Set timeout to %d", timeout);
903 xbt_die("Invalid chord option '%s'", options[0]);
909 const char* platform_file = options[0];
910 const char* application_file = options[1];
914 MSG_create_environment(platform_file);
916 MSG_function_register("node", node);
917 MSG_launch_application(application_file);
919 MSG_error_t res = MSG_main();
920 XBT_CRITICAL("Messages created: %ld", smx_total_comms);
921 XBT_INFO("Simulated time: %g", MSG_get_clock());