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"
13 #include "xbt/xbt_os_time.h"
15 XBT_LOG_NEW_DEFAULT_CATEGORY(msg_chord,
16 "Messages specific for this msg example");
20 #define MAILBOX_NAME_SIZE 10
22 static int nb_bits = 24;
23 static int nb_keys = 0;
24 static int timeout = 50;
25 static int max_simulation_time = 1000;
26 static int periodic_stabilize_delay = 20;
27 static int periodic_fix_fingers_delay = 120;
28 static int periodic_check_predecessor_delay = 120;
29 static int periodic_lookup_delay = 10;
31 extern long int smx_total_comms;
36 typedef struct finger {
38 char mailbox[MAILBOX_NAME_SIZE]; // string representation of the id
39 } s_finger_t, *finger_t;
46 char mailbox[MAILBOX_NAME_SIZE]; // my mailbox name (string representation of the id)
47 s_finger_t *fingers; // finger table, of size nb_bits (fingers[0] is my successor)
48 int pred_id; // predecessor id
49 char pred_mailbox[MAILBOX_NAME_SIZE]; // predecessor's mailbox name
50 int next_finger_to_fix; // index of the next finger to fix in fix_fingers()
51 msg_comm_t comm_receive; // current communication to receive
52 double last_change_date; // last time I changed a finger or my predecessor
56 * Types of tasks exchanged between nodes.
60 TASK_FIND_SUCCESSOR_ANSWER,
62 TASK_GET_PREDECESSOR_ANSWER,
64 TASK_SUCCESSOR_LEAVING,
65 TASK_PREDECESSOR_LEAVING
69 * Data attached with the tasks sent and received
71 typedef struct task_data {
72 e_task_type_t type; // type of task
73 int request_id; // id paramater (used by some types of tasks)
74 int request_finger; // finger parameter (used by some types of tasks)
75 int answer_id; // answer (used by some types of tasks)
76 char answer_to[MAILBOX_NAME_SIZE]; // mailbox to send an answer to (if any)
77 const char* issuer_host_name; // used for logging
78 } s_task_data_t, *task_data_t;
83 static void chord_initialize(void);
84 static void chord_exit(void);
85 static int normalize(int id);
86 static int is_in_interval(int id, int start, int end);
87 static void get_mailbox(int host_id, char* mailbox);
88 static void task_free(void* task);
89 static void print_finger_table(node_t node);
90 static void set_finger(node_t node, int finger_index, int id);
91 static void set_predecessor(node_t node, int predecessor_id);
94 static int node(int argc, char *argv[]);
95 static void handle_task(node_t node, m_task_t task);
98 static void create(node_t node);
99 static int join(node_t node, int known_id);
100 static void leave(node_t node);
101 static int find_successor(node_t node, int id);
102 static int remote_find_successor(node_t node, int ask_to_id, int id);
103 static int remote_get_predecessor(node_t node, int ask_to_id);
104 static int closest_preceding_node(node_t node, int id);
105 static void stabilize(node_t node);
106 static void notify(node_t node, int predecessor_candidate_id);
107 static void remote_notify(node_t node, int notify_to, int predecessor_candidate_id);
108 static void fix_fingers(node_t node);
109 static void check_predecessor(node_t node);
110 static void random_lookup(node_t);
111 static void quit_notify(node_t node, int to);
114 * \brief Global initialization of the Chord simulation.
116 static void chord_initialize(void)
118 // compute the powers of 2 once for all
119 powers2 = xbt_new(int, nb_bits);
122 for (i = 0; i < nb_bits; i++) {
127 XBT_DEBUG("Sets nb_keys to %d", nb_keys);
130 static void chord_exit(void)
136 * \brief Turns an id into an equivalent id in [0, nb_keys).
138 * \return the corresponding normalized id
140 static int normalize(int id)
142 // like id % nb_keys, but works with negatives numbers (and faster)
143 return id & (nb_keys - 1);
147 * \brief Returns whether an id belongs to the interval [start, end].
149 * The parameters are noramlized to make sure they are between 0 and nb_keys - 1).
150 * 1 belongs to [62, 3]
151 * 1 does not belong to [3, 62]
152 * 63 belongs to [62, 3]
153 * 63 does not belong to [3, 62]
154 * 24 belongs to [21, 29]
155 * 24 does not belong to [29, 21]
157 * \param id id to check
158 * \param start lower bound
159 * \param end upper bound
160 * \return a non-zero value if id in in [start, end]
162 static int is_in_interval(int id, int start, int end)
165 start = normalize(start);
166 end = normalize(end);
168 // make sure end >= start and id >= start
181 * \brief Gets the mailbox name of a host given its chord id.
182 * \param node_id id of a node
183 * \param mailbox pointer to where the mailbox name should be written
184 * (there must be enough space)
186 static void get_mailbox(int node_id, char* mailbox)
188 snprintf(mailbox, MAILBOX_NAME_SIZE - 1, "%d", node_id);
192 * \brief Frees the memory used by a task.
193 * \param task the MSG task to destroy
195 static void task_free(void* task)
197 // TODO add a parameter data_free_function to MSG_task_create?
198 xbt_free(MSG_task_get_data(task));
199 MSG_task_destroy(task);
203 * \brief Displays the finger table of a node.
206 static void print_finger_table(node_t node)
208 if (XBT_LOG_ISENABLED(msg_chord, xbt_log_priority_verbose)) {
210 XBT_VERB("My finger table:");
211 XBT_VERB("Start | Succ ");
212 for (i = 0; i < nb_bits; i++) {
213 XBT_VERB(" %3d | %3d ", (node->id + powers2[i]) % nb_keys, node->fingers[i].id);
215 XBT_VERB("Predecessor: %d", node->pred_id);
220 * \brief Sets a finger of the current node.
221 * \param node the current node
222 * \param finger_index index of the finger to set (0 to nb_bits - 1)
223 * \param id the id to set for this finger
225 static void set_finger(node_t node, int finger_index, int id)
227 if (id != node->fingers[finger_index].id) {
228 node->fingers[finger_index].id = id;
229 get_mailbox(id, node->fingers[finger_index].mailbox);
230 node->last_change_date = MSG_get_clock();
231 XBT_DEBUG("My new finger #%d is %d", finger_index, id);
236 * \brief Sets the predecessor of the current node.
237 * \param node the current node
238 * \param id the id to predecessor, or -1 to unset the predecessor
240 static void set_predecessor(node_t node, int predecessor_id)
242 if (predecessor_id != node->pred_id) {
243 node->pred_id = predecessor_id;
245 if (predecessor_id != -1) {
246 get_mailbox(predecessor_id, node->pred_mailbox);
248 node->last_change_date = MSG_get_clock();
250 XBT_DEBUG("My new predecessor is %d", predecessor_id);
255 * \brief Node Function
258 * - the id of a guy I know in the system (except for the first node)
259 * - the time to sleep before I join (except for the first node)
261 int node(int argc, char *argv[])
263 /* Reduce the run size for the MC */
265 periodic_stabilize_delay = 8;
266 periodic_fix_fingers_delay = 8;
267 periodic_check_predecessor_delay = 8;
270 double init_time = MSG_get_clock();
271 m_task_t task_received = NULL;
273 int join_success = 0;
275 double next_stabilize_date = init_time + periodic_stabilize_delay;
276 double next_fix_fingers_date = init_time + periodic_fix_fingers_delay;
277 double next_check_predecessor_date = init_time + periodic_check_predecessor_delay;
278 double next_lookup_date = init_time + periodic_lookup_delay;
280 xbt_assert(argc == 3 || argc == 5, "Wrong number of arguments for this node");
282 // initialize my node
284 node.id = atoi(argv[1]);
285 get_mailbox(node.id, node.mailbox);
286 node.next_finger_to_fix = 0;
287 node.fingers = xbt_new0(s_finger_t, nb_bits);
288 node.last_change_date = init_time;
290 for (i = 0; i < nb_bits; i++) {
291 node.fingers[i].id = -1;
292 set_finger(&node, i, node.id);
295 if (argc == 3) { // first ring
296 deadline = atof(argv[2]);
301 int known_id = atoi(argv[2]);
302 //double sleep_time = atof(argv[3]);
303 deadline = atof(argv[4]);
306 // sleep before starting
307 XBT_DEBUG("Let's sleep during %f", sleep_time);
308 MSG_process_sleep(sleep_time);
310 XBT_DEBUG("Hey! Let's join the system.");
312 join_success = join(&node, known_id);
316 while (MSG_get_clock() < init_time + deadline
317 // && MSG_get_clock() < node.last_change_date + 1000
318 && MSG_get_clock() < max_simulation_time) {
320 if (node.comm_receive == NULL) {
321 task_received = NULL;
322 node.comm_receive = MSG_task_irecv(&task_received, node.mailbox);
323 // FIXME: do not make MSG_task_irecv() calls from several functions
326 if (!MSG_comm_test(node.comm_receive)) {
328 // no task was received: make some periodic calls
329 if (MSG_get_clock() >= next_stabilize_date) {
331 next_stabilize_date = MSG_get_clock() + periodic_stabilize_delay;
333 else if (MSG_get_clock() >= next_fix_fingers_date) {
335 next_fix_fingers_date = MSG_get_clock() + periodic_fix_fingers_delay;
337 else if (MSG_get_clock() >= next_check_predecessor_date) {
338 check_predecessor(&node);
339 next_check_predecessor_date = MSG_get_clock() + periodic_check_predecessor_delay;
341 else if (MSG_get_clock() >= next_lookup_date) {
342 random_lookup(&node);
343 next_lookup_date = MSG_get_clock() + periodic_lookup_delay;
346 // nothing to do: sleep for a while
347 MSG_process_sleep(5);
351 if (node.comm_receive && MSG_comm_test(node.comm_receive)) {
353 // a transfer has occured
355 MSG_error_t status = MSG_comm_get_status(node.comm_receive);
357 if (status != MSG_OK) {
358 XBT_DEBUG("Failed to receive a task. Nevermind.");
359 MSG_comm_destroy(node.comm_receive);
360 node.comm_receive = NULL;
363 // the task was successfully received
364 MSG_comm_destroy(node.comm_receive);
365 node.comm_receive = NULL;
366 handle_task(&node, task_received);
371 if (node.comm_receive) {
372 MSG_comm_destroy(node.comm_receive);
373 node.comm_receive = NULL;
380 // stop the simulation
381 xbt_free(node.fingers);
386 * \brief This function is called when the current node receives a task.
387 * \param node the current node
388 * \param task the task to handle (don't touch it then:
389 * it will be destroyed, reused or forwarded)
391 static void handle_task(node_t node, m_task_t task) {
393 XBT_DEBUG("Handling task %p", task);
394 char mailbox[MAILBOX_NAME_SIZE];
395 task_data_t task_data = (task_data_t) MSG_task_get_data(task);
396 e_task_type_t type = task_data->type;
400 case TASK_FIND_SUCCESSOR:
401 XBT_DEBUG("Receiving a 'Find Successor' request from %s for id %d",
402 task_data->issuer_host_name, task_data->request_id);
403 // is my successor the successor?
404 if (is_in_interval(task_data->request_id, node->id + 1, node->fingers[0].id)) {
405 task_data->type = TASK_FIND_SUCCESSOR_ANSWER;
406 task_data->answer_id = node->fingers[0].id;
407 XBT_DEBUG("Sending back a 'Find Successor Answer' to %s (mailbox %s): the successor of %d is %d",
408 task_data->issuer_host_name,
409 task_data->answer_to,
410 task_data->request_id, task_data->answer_id);
411 MSG_task_dsend(task, task_data->answer_to, task_free);
414 // otherwise, forward the request to the closest preceding finger in my table
415 int closest = closest_preceding_node(node, task_data->request_id);
416 XBT_DEBUG("Forwarding the 'Find Successor' request for id %d to my closest preceding finger %d",
417 task_data->request_id, closest);
418 get_mailbox(closest, mailbox);
419 MSG_task_dsend(task, mailbox, task_free);
423 case TASK_GET_PREDECESSOR:
424 XBT_DEBUG("Receiving a 'Get Predecessor' request from %s", task_data->issuer_host_name);
425 task_data->type = TASK_GET_PREDECESSOR_ANSWER;
426 task_data->answer_id = node->pred_id;
427 XBT_DEBUG("Sending back a 'Get Predecessor Answer' to %s via mailbox '%s': my predecessor is %d",
428 task_data->issuer_host_name,
429 task_data->answer_to, task_data->answer_id);
430 MSG_task_dsend(task, task_data->answer_to, task_free);
434 // someone is telling me that he may be my new predecessor
435 XBT_DEBUG("Receiving a 'Notify' request from %s", task_data->issuer_host_name);
436 notify(node, task_data->request_id);
440 case TASK_PREDECESSOR_LEAVING:
441 // my predecessor is about to quit
442 XBT_DEBUG("Receiving a 'Predecessor Leaving' message from %s", task_data->issuer_host_name);
443 // modify my predecessor
444 set_predecessor(node, task_data->request_id);
447 >> notify my new predecessor
448 >> send a notify_predecessors !!
452 case TASK_SUCCESSOR_LEAVING:
453 // my successor is about to quit
454 XBT_DEBUG("Receiving a 'Successor Leaving' message from %s", task_data->issuer_host_name);
455 // modify my successor FIXME : this should be implicit ?
456 set_finger(node, 0, task_data->request_id);
459 >> notify my new successor
460 >> update my table & predecessors table */
463 case TASK_FIND_SUCCESSOR_ANSWER:
464 case TASK_GET_PREDECESSOR_ANSWER:
465 XBT_DEBUG("Ignoring unexpected task of type %d (%p)", type, task);
472 * \brief Initializes the current node as the first one of the system.
473 * \param node the current node
475 static void create(node_t node)
477 XBT_DEBUG("Create a new Chord ring...");
478 set_predecessor(node, -1); // -1 means that I have no predecessor
479 print_finger_table(node);
483 * \brief Makes the current node join the ring, knowing the id of a node
484 * already in the ring
485 * \param node the current node
486 * \param known_id id of a node already in the ring
487 * \return 1 if the join operation succeeded, 0 otherwise
489 static int join(node_t node, int known_id)
491 XBT_INFO("Joining the ring with id %d, knowing node %d", node->id, known_id);
492 set_predecessor(node, -1); // no predecessor (yet)
496 for (i = 0; i < nb_bits; i++) {
497 set_finger(node, i, known_id);
501 int successor_id = remote_find_successor(node, known_id, node->id);
502 if (successor_id == -1) {
503 XBT_INFO("Cannot join the ring.");
506 set_finger(node, 0, successor_id);
507 print_finger_table(node);
510 return successor_id != -1;
514 * \brief Makes the current node quit the system
515 * \param node the current node
517 static void leave(node_t node)
519 XBT_DEBUG("Well Guys! I Think it's time for me to quit ;)");
520 quit_notify(node, 1); // notify to my successor ( >>> 1 );
521 quit_notify(node, -1); // notify my predecessor ( >>> -1);
526 * \brief Notifies the successor or the predecessor of the current node
528 * \param node the current node
529 * \param to 1 to notify the successor, -1 to notify the predecessor
530 * FIXME: notify both nodes with only one call
532 static void quit_notify(node_t node, int to)
535 task_data_t req_data = xbt_new0(s_task_data_t, 1);
536 req_data->request_id = node->id;
537 req_data->successor_id = node->fingers[0].id;
538 req_data->pred_id = node->pred_id;
539 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
540 req_data->answer_to = NULL;
541 const char* task_name = NULL;
542 const char* to_mailbox = NULL;
543 if (to == 1) { // notify my successor
544 to_mailbox = node->fingers[0].mailbox;
545 XBT_INFO("Telling my Successor %d about my departure via mailbox %s",
546 node->fingers[0].id, to_mailbox);
547 req_data->type = TASK_PREDECESSOR_LEAVING;
549 else if (to == -1) { // notify my predecessor
551 if (node->pred_id == -1) {
555 to_mailbox = node->pred_mailbox;
556 XBT_INFO("Telling my Predecessor %d about my departure via mailbox %s",
557 node->pred_id, to_mailbox);
558 req_data->type = TASK_SUCCESSOR_LEAVING;
560 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
561 //char* mailbox = get_mailbox(to_mailbox);
562 msg_comm_t comm = MSG_task_isend(task, to_mailbox);
563 xbt_dynar_push(node->comms, &comm);
568 * \brief Makes the current node find the successor node of an id.
569 * \param node the current node
570 * \param id the id to find
571 * \return the id of the successor node, or -1 if the request failed
573 static int find_successor(node_t node, int id)
575 // is my successor the successor?
576 if (is_in_interval(id, node->id + 1, node->fingers[0].id)) {
577 return node->fingers[0].id;
580 // otherwise, ask the closest preceding finger in my table
581 int closest = closest_preceding_node(node, id);
582 return remote_find_successor(node, closest, id);
586 * \brief Asks another node the successor node of an id.
587 * \param node the current node
588 * \param ask_to the node to ask to
589 * \param id the id to find
590 * \return the id of the successor node, or -1 if the request failed
592 static int remote_find_successor(node_t node, int ask_to, int id)
596 char mailbox[MAILBOX_NAME_SIZE];
597 get_mailbox(ask_to, mailbox);
598 task_data_t req_data = xbt_new0(s_task_data_t, 1);
599 req_data->type = TASK_FIND_SUCCESSOR;
600 req_data->request_id = id;
601 get_mailbox(node->id, req_data->answer_to);
602 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
604 // send a "Find Successor" request to ask_to_id
605 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
606 XBT_DEBUG("Sending a 'Find Successor' request (task %p) to %d for id %d", task_sent, ask_to, id);
607 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
610 XBT_DEBUG("Failed to send the 'Find Successor' request (task %p) to %d for id %d",
611 task_sent, ask_to, id);
612 task_free(task_sent);
616 // receive the answer
617 XBT_DEBUG("Sent a 'Find Successor' request (task %p) to %d for key %d, waiting for the answer",
618 task_sent, ask_to, id);
621 if (node->comm_receive == NULL) {
622 m_task_t task_received = NULL;
623 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
626 res = MSG_comm_wait(node->comm_receive, timeout);
629 XBT_DEBUG("Failed to receive the answer to my 'Find Successor' request (task %p): %d",
632 MSG_comm_destroy(node->comm_receive);
633 node->comm_receive = NULL;
636 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
637 XBT_DEBUG("Received a task (%p)", task_received);
638 task_data_t ans_data = MSG_task_get_data(task_received);
641 MC_assert(task_received == task_sent);
644 if (task_received != task_sent) {
645 // this is not the expected answer
646 MSG_comm_destroy(node->comm_receive);
647 node->comm_receive = NULL;
648 handle_task(node, task_received);
651 // this is our answer
652 XBT_DEBUG("Received the answer to my 'Find Successor' request for id %d (task %p): the successor of key %d is %d",
653 ans_data->request_id, task_received, id, ans_data->answer_id);
654 successor = ans_data->answer_id;
656 MSG_comm_destroy(node->comm_receive);
657 node->comm_receive = NULL;
658 task_free(task_received);
668 * \brief Asks another node its predecessor.
669 * \param node the current node
670 * \param ask_to the node to ask to
671 * \return the id of its predecessor node, or -1 if the request failed
672 * (or if the node does not know its predecessor)
674 static int remote_get_predecessor(node_t node, int ask_to)
676 int predecessor_id = -1;
678 char mailbox[MAILBOX_NAME_SIZE];
679 get_mailbox(ask_to, mailbox);
680 task_data_t req_data = xbt_new0(s_task_data_t, 1);
681 req_data->type = TASK_GET_PREDECESSOR;
682 get_mailbox(node->id, req_data->answer_to);
683 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
685 // send a "Get Predecessor" request to ask_to_id
686 XBT_DEBUG("Sending a 'Get Predecessor' request to %d", ask_to);
687 m_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
688 MSG_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
691 XBT_DEBUG("Failed to send the 'Get Predecessor' request (task %p) to %d",
693 task_free(task_sent);
697 // receive the answer
698 XBT_DEBUG("Sent 'Get Predecessor' request (task %p) to %d, waiting for the answer on my mailbox '%s'",
699 task_sent, ask_to, req_data->answer_to);
702 if (node->comm_receive == NULL) { // FIXME simplify this
703 m_task_t task_received = NULL;
704 node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
707 res = MSG_comm_wait(node->comm_receive, timeout);
710 XBT_DEBUG("Failed to receive the answer to my 'Get Predecessor' request (task %p): %d",
713 MSG_comm_destroy(node->comm_receive);
714 node->comm_receive = NULL;
717 m_task_t task_received = MSG_comm_get_task(node->comm_receive);
718 task_data_t ans_data = MSG_task_get_data(task_received);
721 MC_assert(task_received == task_sent);
724 if (task_received != task_sent) {
725 MSG_comm_destroy(node->comm_receive);
726 node->comm_receive = NULL;
727 handle_task(node, task_received);
730 XBT_DEBUG("Received the answer to my 'Get Predecessor' request (task %p): the predecessor of node %d is %d",
731 task_received, ask_to, ans_data->answer_id);
732 predecessor_id = ans_data->answer_id;
734 MSG_comm_destroy(node->comm_receive);
735 node->comm_receive = NULL;
736 task_free(task_received);
742 return predecessor_id;
746 * \brief Returns the closest preceding finger of an id
747 * with respect to the finger table of the current node.
748 * \param node the current node
749 * \param id the id to find
750 * \return the closest preceding finger of that id
752 int closest_preceding_node(node_t node, int id)
755 for (i = nb_bits - 1; i >= 0; i--) {
756 if (is_in_interval(node->fingers[i].id, node->id + 1, id - 1)) {
757 return node->fingers[i].id;
764 * \brief This function is called periodically. It checks the immediate
765 * successor of the current node.
766 * \param node the current node
768 static void stabilize(node_t node)
770 XBT_DEBUG("Stabilizing node");
772 // get the predecessor of my immediate successor
774 int successor_id = node->fingers[0].id;
775 if (successor_id != node->id) {
776 candidate_id = remote_get_predecessor(node, successor_id);
779 candidate_id = node->pred_id;
782 // this node is a candidate to become my new successor
783 if (candidate_id != -1
784 && is_in_interval(candidate_id, node->id + 1, successor_id - 1)) {
785 set_finger(node, 0, candidate_id);
787 if (successor_id != node->id) {
788 remote_notify(node, successor_id, node->id);
793 * \brief Notifies the current node that its predecessor may have changed.
794 * \param node the current node
795 * \param candidate_id the possible new predecessor
797 static void notify(node_t node, int predecessor_candidate_id) {
799 if (node->pred_id == -1
800 || is_in_interval(predecessor_candidate_id, node->pred_id + 1, node->id - 1)) {
802 set_predecessor(node, predecessor_candidate_id);
803 print_finger_table(node);
806 XBT_DEBUG("I don't have to change my predecessor to %d", predecessor_candidate_id);
811 * \brief Notifies a remote node that its predecessor may have changed.
812 * \param node the current node
813 * \param notify_id id of the node to notify
814 * \param candidate_id the possible new predecessor
816 static void remote_notify(node_t node, int notify_id, int predecessor_candidate_id) {
818 task_data_t req_data = xbt_new0(s_task_data_t, 1);
819 req_data->type = TASK_NOTIFY;
820 req_data->request_id = predecessor_candidate_id;
821 req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
823 // send a "Notify" request to notify_id
824 m_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
825 XBT_DEBUG("Sending a 'Notify' request (task %p) to %d", task, notify_id);
826 char mailbox[MAILBOX_NAME_SIZE];
827 get_mailbox(notify_id, mailbox);
828 MSG_task_dsend(task, mailbox, task_free);
832 * \brief This function is called periodically.
833 * It refreshes the finger table of the current node.
834 * \param node the current node
836 static void fix_fingers(node_t node) {
838 XBT_DEBUG("Fixing fingers");
839 int i = node->next_finger_to_fix;
840 int id = find_successor(node, node->id + powers2[i]);
843 if (id != node->fingers[i].id) {
844 set_finger(node, i, id);
845 print_finger_table(node);
847 node->next_finger_to_fix = (i + 1) % nb_bits;
852 * \brief This function is called periodically.
853 * It checks whether the predecessor has failed
854 * \param node the current node
856 static void check_predecessor(node_t node)
858 XBT_DEBUG("Checking whether my predecessor is alive");
863 * \brief Performs a find successor request to a random id.
864 * \param node the current node
866 static void random_lookup(node_t node)
868 int id = 1337; // TODO pick a pseudorandom id
869 XBT_DEBUG("Making a lookup request for id %d", id);
870 find_successor(node, id);
874 * \brief Main function.
876 int main(int argc, char *argv[])
878 MSG_global_init(&argc, 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 char **options = &argv[1];
886 while (!strncmp(options[0], "-", 1)) {
888 int length = strlen("-nb_bits=");
889 if (!strncmp(options[0], "-nb_bits=", length) && strlen(options[0]) > length) {
890 nb_bits = atoi(options[0] + length);
891 XBT_DEBUG("Set nb_bits to %d", nb_bits);
895 length = strlen("-timeout=");
896 if (!strncmp(options[0], "-timeout=", length) && strlen(options[0]) > length) {
897 timeout = atoi(options[0] + length);
898 XBT_DEBUG("Set timeout to %d", timeout);
901 xbt_die("Invalid chord option '%s'", options[0]);
907 const char* platform_file = options[0];
908 const char* application_file = options[1];
912 MSG_create_environment(platform_file);
914 MSG_function_register("node", node);
915 MSG_launch_application(application_file);
917 MSG_error_t res = MSG_main();
918 XBT_CRITICAL("Messages created: %ld", smx_total_comms);
919 XBT_INFO("Simulated time: %g", MSG_get_clock());