SimGrid  3.16
Versatile Simulation of Distributed Systems
examples/msg/dht-chord/dht-chord.c
/* Copyright (c) 2010-2016. The SimGrid Team. All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
#include "dht-chord.h"
XBT_LOG_NEW_DEFAULT_CATEGORY(msg_chord, "Messages specific for this msg example");
static int nb_bits = 24;
static int nb_keys = 0;
static int timeout = 50;
static int max_simulation_time = 1000;
static int periodic_stabilize_delay = 20;
static int periodic_fix_fingers_delay = 120;
static int periodic_check_predecessor_delay = 120;
static int periodic_lookup_delay = 10;
static const double sleep_delay = 4.9999;
static int *powers2;
/* Global initialization of the Chord simulation. */
static void chord_initialize(void)
{
// compute the powers of 2 once for all
powers2 = xbt_new(int, nb_bits);
unsigned int pow = 1;
unsigned i;
for (i = 0; i < nb_bits; i++) {
powers2[i] = pow;
pow = pow << 1;
}
nb_keys = pow;
XBT_DEBUG("Sets nb_keys to %d", nb_keys);
host_list = MSG_hosts_as_dynar();
xbt_dynar_foreach(host_list, i, host) {
char descr[512];
snprintf(descr, sizeof descr, "RngSream<%s>", MSG_host_get_name(host));
stream = RngStream_CreateStream(descr);
MSG_host_set_data(host, stream);
}
}
static void chord_exit(void)
{
unsigned i;
xbt_dynar_foreach(host_list, i, host) {
MSG_host_set_data(host, NULL);
}
xbt_dynar_free(&host_list);
xbt_free(powers2);
}
/* Turns an id into an equivalent id in [0, nb_keys). */
static int normalize(int id)
{
return id % nb_keys;
}
/* Returns whether an id belongs to the interval [start, end].
*
* The parameters are normalized to make sure they are between 0 and nb_keys - 1).
* 1 belongs to [62, 3]
* 1 does not belong to [3, 62]
* 63 belongs to [62, 3]
* 63 does not belong to [3, 62]
* 24 belongs to [21, 29]
* 24 does not belong to [29, 21]
*
* \param id id to check
* \param start lower bound
* \param end upper bound
* \return a non-zero value if id in in [start, end]
*/
static int is_in_interval(int id, int start, int end)
{
int i = normalize(id);
int s = normalize(start);
int e = normalize(end);
// make sure end >= start and id >= start
if (e < s) {
e += nb_keys;
}
if (i < s) {
i += nb_keys;
}
return i <= e;
}
/* Gets the mailbox name of a host given its chord id.
* \param node_id id of a node
* \param mailbox pointer to where the mailbox name should be written
* (there must be enough space)
*/
static void get_mailbox(int node_id, char* mailbox)
{
snprintf(mailbox, MAILBOX_NAME_SIZE - 1, "%d", node_id);
}
/* Frees the memory used by a task and destroy it */
static void task_free(void* task)
{
// TODO add a parameter data_free_function to MSG_task_create?
if(task != NULL){
}
}
/* Displays the finger table of a node. */
static void print_finger_table(node_t node)
{
XBT_VERB("My finger table:");
XBT_VERB("Start | Succ");
for (int i = 0; i < nb_bits; i++) {
XBT_VERB(" %3d | %3d", (node->id + powers2[i]) % nb_keys, node->fingers[i].id);
}
XBT_VERB("Predecessor: %d", node->pred_id);
}
}
/* Sets a finger of the current node.
*
* \param node the current node
* \param finger_index index of the finger to set (0 to nb_bits - 1)
* \param id the id to set for this finger
*/
static void set_finger(node_t node, int finger_index, int id)
{
if (id != node->fingers[finger_index].id) {
node->fingers[finger_index].id = id;
get_mailbox(id, node->fingers[finger_index].mailbox);
node->last_change_date = MSG_get_clock();
XBT_DEBUG("My new finger #%d is %d", finger_index, id);
}
}
/* Sets the predecessor of the current node.
*
* \param node the current node
* \param id the id to predecessor, or -1 to unset the predecessor
*/
static void set_predecessor(node_t node, int predecessor_id)
{
if (predecessor_id != node->pred_id) {
node->pred_id = predecessor_id;
if (predecessor_id != -1) {
get_mailbox(predecessor_id, node->pred_mailbox);
}
node->last_change_date = MSG_get_clock();
XBT_DEBUG("My new predecessor is %d", predecessor_id);
}
}
/* Node main Function
*
* Arguments:
* - my id
* - the id of a guy I know in the system (except for the first node)
* - the time to sleep before I join (except for the first node)
*/
/* This function is called when the current node receives a task.
*
* \param node the current node
* \param task the task to handle (don't touch it afterward: it will be destroyed, reused or forwarded)
*/
static void handle_task(node_t node, msg_task_t task)
{
XBT_DEBUG("Handling task %p", task);
char mailbox[MAILBOX_NAME_SIZE];
task_data_t task_data = (task_data_t) MSG_task_get_data(task);
e_task_type_t type = task_data->type;
switch (type) {
case TASK_FIND_SUCCESSOR:
XBT_DEBUG("Receiving a 'Find Successor' request from %s for id %d",
task_data->issuer_host_name, task_data->request_id);
// is my successor the successor?
if (is_in_interval(task_data->request_id, node->id + 1, node->fingers[0].id)) {
task_data->type = TASK_FIND_SUCCESSOR_ANSWER;
task_data->answer_id = node->fingers[0].id;
XBT_DEBUG("Sending back a 'Find Successor Answer' to %s (mailbox %s): the successor of %d is %d",
task_data->issuer_host_name, task_data->answer_to, task_data->request_id, task_data->answer_id);
MSG_task_dsend(task, task_data->answer_to, task_free);
} else {
// otherwise, forward the request to the closest preceding finger in my table
int closest = closest_preceding_node(node, task_data->request_id);
XBT_DEBUG("Forwarding the 'Find Successor' request for id %d to my closest preceding finger %d",
task_data->request_id, closest);
get_mailbox(closest, mailbox);
MSG_task_dsend(task, mailbox, task_free);
}
break;
case TASK_GET_PREDECESSOR:
XBT_DEBUG("Receiving a 'Get Predecessor' request from %s", task_data->issuer_host_name);
task_data->type = TASK_GET_PREDECESSOR_ANSWER;
task_data->answer_id = node->pred_id;
XBT_DEBUG("Sending back a 'Get Predecessor Answer' to %s via mailbox '%s': my predecessor is %d",
task_data->issuer_host_name, task_data->answer_to, task_data->answer_id);
MSG_task_dsend(task, task_data->answer_to, task_free);
break;
case TASK_NOTIFY:
// someone is telling me that he may be my new predecessor
XBT_DEBUG("Receiving a 'Notify' request from %s", task_data->issuer_host_name);
notify(node, task_data->request_id);
task_free(task);
break;
case TASK_PREDECESSOR_LEAVING:
// my predecessor is about to quit
XBT_DEBUG("Receiving a 'Predecessor Leaving' message from %s", task_data->issuer_host_name);
// modify my predecessor
set_predecessor(node, task_data->request_id);
task_free(task);
/*TODO :
>> notify my new predecessor
>> send a notify_predecessors !!
*/
break;
case TASK_SUCCESSOR_LEAVING:
// my successor is about to quit
XBT_DEBUG("Receiving a 'Successor Leaving' message from %s", task_data->issuer_host_name);
// modify my successor FIXME : this should be implicit ?
set_finger(node, 0, task_data->request_id);
task_free(task);
/* TODO
>> notify my new successor
>> update my table & predecessors table */
break;
case TASK_FIND_SUCCESSOR_ANSWER:
case TASK_GET_PREDECESSOR_ANSWER:
case TASK_PREDECESSOR_ALIVE_ANSWER:
XBT_DEBUG("Ignoring unexpected task of type %d (%p)", (int)type, task);
task_free(task);
break;
case TASK_PREDECESSOR_ALIVE:
XBT_DEBUG("Receiving a 'Predecessor Alive' request from %s", task_data->issuer_host_name);
task_data->type = TASK_PREDECESSOR_ALIVE_ANSWER;
XBT_DEBUG("Sending back a 'Predecessor Alive Answer' to %s (mailbox %s)",
task_data->issuer_host_name, task_data->answer_to);
MSG_task_dsend(task, task_data->answer_to, task_free);
break;
default:
}
}
/* Initializes the current node as the first one of the system */
void create(node_t node)
{
XBT_DEBUG("Create a new Chord ring...");
set_predecessor(node, -1); // -1 means that I have no predecessor
print_finger_table(node);
}
/* Makes the current node join the ring, knowing the id of a node already in the ring
*
* \param node the current node
* \param known_id id of a node already in the ring
* \return 1 if the join operation succeeded, 0 otherwise
*/
int join(node_t node, int known_id)
{
XBT_INFO("Joining the ring with id %d, knowing node %d", node->id, known_id);
set_predecessor(node, -1); // no predecessor (yet)
int successor_id = remote_find_successor(node, known_id, node->id);
if (successor_id == -1) {
XBT_INFO("Cannot join the ring.");
}
else {
set_finger(node, 0, successor_id);
print_finger_table(node);
}
return successor_id != -1;
}
/* Makes the current node quit the system */
void leave(node_t node)
{
XBT_DEBUG("Well Guys! I Think it's time for me to quit ;)");
quit_notify(node);
}
/* Notifies the successor and the predecessor of the current node before leaving */
void quit_notify(node_t node)
{
char mailbox[MAILBOX_NAME_SIZE];
//send the PREDECESSOR_LEAVING to our successor
task_data_t req_data = xbt_new0(s_task_data_t,1);
req_data->type = TASK_PREDECESSOR_LEAVING;
req_data->request_id = node->pred_id;
get_mailbox(node->id, req_data->answer_to);
req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
msg_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
XBT_DEBUG("Sending a 'PREDECESSOR_LEAVING' to my successor %d",node->fingers[0].id);
if (MSG_task_send_with_timeout(task_sent, node->fingers[0].mailbox, timeout)== MSG_TIMEOUT) {
XBT_DEBUG("Timeout expired when sending a 'PREDECESSOR_LEAVING' to my successor %d", node->fingers[0].id);
task_free(task_sent);
}
//send the SUCCESSOR_LEAVING to our predecessor
get_mailbox(node->pred_id, mailbox);
task_data_t req_data_s = xbt_new0(s_task_data_t,1);
req_data_s->type = TASK_SUCCESSOR_LEAVING;
req_data_s->request_id = node->pred_id;
get_mailbox(node->id, req_data_s->answer_to);
req_data_s->issuer_host_name = MSG_host_get_name(MSG_host_self());
msg_task_t task_sent_s = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data_s);
XBT_DEBUG("Sending a 'SUCCESSOR_LEAVING' to my predecessor %d",node->pred_id);
if (MSG_task_send_with_timeout(task_sent_s, mailbox, timeout)== MSG_TIMEOUT) {
XBT_DEBUG("Timeout expired when sending a 'SUCCESSOR_LEAVING' to my predecessor %d", node->pred_id);
task_free(task_sent_s);
}
}
/* Makes the current node find the successor node of an id.
*
* \param node the current node
* \param id the id to find
* \return the id of the successor node, or -1 if the request failed
*/
int find_successor(node_t node, int id)
{
// is my successor the successor?
if (is_in_interval(id, node->id + 1, node->fingers[0].id)) {
return node->fingers[0].id;
}
// otherwise, ask the closest preceding finger in my table
int closest = closest_preceding_node(node, id);
return remote_find_successor(node, closest, id);
}
/* \brief Asks another node the successor node of an id.
*
* \param node the current node
* \param ask_to the node to ask to
* \param id the id to find
* \return the id of the successor node, or -1 if the request failed
*/
int remote_find_successor(node_t node, int ask_to, int id)
{
int successor = -1;
char mailbox[MAILBOX_NAME_SIZE];
get_mailbox(ask_to, mailbox);
task_data_t req_data = xbt_new0(s_task_data_t, 1);
req_data->type = TASK_FIND_SUCCESSOR;
req_data->request_id = id;
get_mailbox(node->id, req_data->answer_to);
req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
// send a "Find Successor" request to ask_to_id
msg_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
XBT_DEBUG("Sending a 'Find Successor' request (task %p) to %d for id %d", task_sent, ask_to, id);
msg_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
if (res != MSG_OK) {
XBT_DEBUG("Failed to send the 'Find Successor' request (task %p) to %d for id %d", task_sent, ask_to, id);
task_free(task_sent);
} else {
int stop = 0;
// receive the answer
XBT_DEBUG("Sent a 'Find Successor' request (task %p) to %d for key %d, waiting for the answer",
task_sent, ask_to, id);
do {
if (node->comm_receive == NULL) {
msg_task_t task_received = NULL;
node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
}
res = MSG_comm_wait(node->comm_receive, timeout);
if (res != MSG_OK) {
XBT_DEBUG("Failed to receive the answer to my 'Find Successor' request (task %p): %d",
task_sent, (int)res);
stop = 1;
MSG_comm_destroy(node->comm_receive);
node->comm_receive = NULL;
}
else {
msg_task_t task_received = MSG_comm_get_task(node->comm_receive);
XBT_DEBUG("Received a task (%p)", task_received);
task_data_t ans_data = MSG_task_get_data(task_received);
// Once upon a time, our code assumed that here, task_received != task_sent all the time
//
// This assumption is wrong (as messages from differing round can interleave), leading to a bug in our code.
// We failed to find this bug directly, as it only occurred on large platforms, leading to hardly usable traces.
// Instead, we used the model-checker to track down the issue by adding the following test here in the code:
// if (MC_is_active()) {
// MC_assert(task_received == task_sent);
// }
// That explained the bug in a snap, with a very cool example and everything.
//
// This MC_assert is now deactivated as the case is now properly handled in our code and we don't want the
// MC to fail any further under that condition, but this comment is here to as a memorial for this first
// brilliant victory of the model-checking in the SimGrid community :)
if (task_received != task_sent ||
ans_data->type != TASK_FIND_SUCCESSOR_ANSWER) {
// this is not the expected answer
MSG_comm_destroy(node->comm_receive);
node->comm_receive = NULL;
handle_task(node, task_received);
}
else {
// this is our answer
XBT_DEBUG("Received the answer to my 'Find Successor' request for id %d (task %p): the successor of key %d is %d",
ans_data->request_id, task_received, id, ans_data->answer_id);
successor = ans_data->answer_id;
stop = 1;
MSG_comm_destroy(node->comm_receive);
node->comm_receive = NULL;
task_free(task_received);
}
}
} while (!stop);
}
return successor;
}
/* Asks its predecessor to a remote node
*
* \param node the current node
* \param ask_to the node to ask to
* \return the id of its predecessor node, or -1 if the request failed
* (or if the node does not know its predecessor)
*/
int remote_get_predecessor(node_t node, int ask_to)
{
int predecessor_id = -1;
int stop = 0;
char mailbox[MAILBOX_NAME_SIZE];
get_mailbox(ask_to, mailbox);
task_data_t req_data = xbt_new0(s_task_data_t, 1);
req_data->type = TASK_GET_PREDECESSOR;
get_mailbox(node->id, req_data->answer_to);
req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
// send a "Get Predecessor" request to ask_to_id
XBT_DEBUG("Sending a 'Get Predecessor' request to %d", ask_to);
msg_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
msg_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
if (res != MSG_OK) {
XBT_DEBUG("Failed to send the 'Get Predecessor' request (task %p) to %d",
task_sent, ask_to);
task_free(task_sent);
}
else {
// receive the answer
XBT_DEBUG("Sent 'Get Predecessor' request (task %p) to %d, waiting for the answer on my mailbox '%s'",
task_sent, ask_to, req_data->answer_to);
do {
if (node->comm_receive == NULL) { // FIXME simplify this
msg_task_t task_received = NULL;
node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
}
res = MSG_comm_wait(node->comm_receive, timeout);
if (res != MSG_OK) {
XBT_DEBUG("Failed to receive the answer to my 'Get Predecessor' request (task %p): %d",
task_sent, (int)res);
stop = 1;
MSG_comm_destroy(node->comm_receive);
node->comm_receive = NULL;
}
else {
msg_task_t task_received = MSG_comm_get_task(node->comm_receive);
task_data_t ans_data = MSG_task_get_data(task_received);
/*if (MC_is_active()) {
MC_assert(task_received == task_sent);
}*/
if (task_received != task_sent ||
ans_data->type != TASK_GET_PREDECESSOR_ANSWER) {
MSG_comm_destroy(node->comm_receive);
node->comm_receive = NULL;
handle_task(node, task_received);
}
else {
XBT_DEBUG("Received the answer to my 'Get Predecessor' request (task %p): the predecessor of node %d is %d",
task_received, ask_to, ans_data->answer_id);
predecessor_id = ans_data->answer_id;
stop = 1;
MSG_comm_destroy(node->comm_receive);
node->comm_receive = NULL;
task_free(task_received);
}
}
} while (!stop);
}
return predecessor_id;
}
/* Returns the closest preceding finger of an id with respect to the finger table of the current node.
*
* \param node the current node
* \param id the id to find
* \return the closest preceding finger of that id
*/
int closest_preceding_node(node_t node, int id)
{
int i;
for (i = nb_bits - 1; i >= 0; i--) {
if (is_in_interval(node->fingers[i].id, node->id + 1, id - 1)) {
return node->fingers[i].id;
}
}
return node->id;
}
/* This function is called periodically. It checks the immediate successor of the current node. */
void stabilize(node_t node)
{
XBT_DEBUG("Stabilizing node");
// get the predecessor of my immediate successor
int candidate_id;
int successor_id = node->fingers[0].id;
if (successor_id != node->id) {
candidate_id = remote_get_predecessor(node, successor_id);
}
else {
candidate_id = node->pred_id;
}
// this node is a candidate to become my new successor
if (candidate_id != -1
&& is_in_interval(candidate_id, node->id + 1, successor_id - 1)) {
set_finger(node, 0, candidate_id);
}
if (successor_id != node->id) {
remote_notify(successor_id, node->id);
}
}
/* Notifies the current node that its predecessor may have changed. */
void notify(node_t node, int predecessor_candidate_id) {
if (node->pred_id == -1
|| is_in_interval(predecessor_candidate_id, node->pred_id + 1, node->id - 1)) {
set_predecessor(node, predecessor_candidate_id);
print_finger_table(node);
}
else {
XBT_DEBUG("I don't have to change my predecessor to %d", predecessor_candidate_id);
}
}
/* Notifies a remote node that its predecessor may have changed. */
void remote_notify(int notify_id, int predecessor_candidate_id) {
task_data_t req_data = xbt_new0(s_task_data_t, 1);
req_data->type = TASK_NOTIFY;
req_data->request_id = predecessor_candidate_id;
req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
// send a "Notify" request to notify_id
msg_task_t task = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
XBT_DEBUG("Sending a 'Notify' request (task %p) to %d", task, notify_id);
char mailbox[MAILBOX_NAME_SIZE];
get_mailbox(notify_id, mailbox);
MSG_task_dsend(task, mailbox, task_free);
}
/* refreshes the finger table of the current node (called periodically) */
void fix_fingers(node_t node) {
XBT_DEBUG("Fixing fingers");
int i = node->next_finger_to_fix;
int id = find_successor(node, node->id + powers2[i]);
if (id != -1) {
if (id != node->fingers[i].id) {
set_finger(node, i, id);
print_finger_table(node);
}
node->next_finger_to_fix = (i + 1) % nb_bits;
}
}
/* checks whether the predecessor has failed (called periodically) */
void check_predecessor(node_t node)
{
XBT_DEBUG("Checking whether my predecessor is alive");
if(node->pred_id == -1)
return;
int stop = 0;
char mailbox[MAILBOX_NAME_SIZE];
get_mailbox(node->pred_id, mailbox);
task_data_t req_data = xbt_new0(s_task_data_t,1);
req_data->type = TASK_PREDECESSOR_ALIVE;
req_data->request_id = node->pred_id;
get_mailbox(node->id, req_data->answer_to);
req_data->issuer_host_name = MSG_host_get_name(MSG_host_self());
msg_task_t task_sent = MSG_task_create(NULL, COMP_SIZE, COMM_SIZE, req_data);
XBT_DEBUG("Sending a 'Predecessor Alive' request to my predecessor %d", node->pred_id);
msg_error_t res = MSG_task_send_with_timeout(task_sent, mailbox, timeout);
if (res != MSG_OK) {
XBT_DEBUG("Failed to send the 'Predecessor Alive' request (task %p) to %d", task_sent, node->pred_id);
task_free(task_sent);
} else {
// receive the answer
XBT_DEBUG("Sent 'Predecessor Alive' request (task %p) to %d, waiting for the answer on my mailbox '%s'",
task_sent, node->pred_id, req_data->answer_to);
do {
if (node->comm_receive == NULL) { // FIXME simplify this
msg_task_t task_received = NULL;
node->comm_receive = MSG_task_irecv(&task_received, node->mailbox);
}
res = MSG_comm_wait(node->comm_receive, timeout);
if (res != MSG_OK) {
XBT_DEBUG("Failed to receive the answer to my 'Predecessor Alive' request (task %p): %d",
task_sent, (int)res);
stop = 1;
MSG_comm_destroy(node->comm_receive);
node->comm_receive = NULL;
node->pred_id = -1;
} else {
msg_task_t task_received = MSG_comm_get_task(node->comm_receive);
if (task_received != task_sent) {
MSG_comm_destroy(node->comm_receive);
node->comm_receive = NULL;
handle_task(node, task_received);
}else{
XBT_DEBUG("Received the answer to my 'Predecessor Alive' request (task %p) : my predecessor %d is alive",
task_received, node->pred_id);
stop = 1;
MSG_comm_destroy(node->comm_receive);
node->comm_receive = NULL;
task_free(task_received);
}
}
} while (!stop);
}
}
/* Performs a find successor request to a random id */
void random_lookup(node_t node)
{
int random_index = RngStream_RandInt (node->stream, 0, nb_bits - 1);
int random_id = node->fingers[random_index].id;
XBT_DEBUG("Making a lookup request for id %d", random_id);
int res = find_successor(node, random_id);
XBT_DEBUG("The successor of node %d is %d", random_id, res);
}
static int node(int argc, char *argv[])
{
/* Reduce the run size for the MC */
periodic_stabilize_delay = 8;
periodic_fix_fingers_delay = 8;
periodic_check_predecessor_delay = 8;
}
double init_time = MSG_get_clock();
msg_task_t task_received = NULL;
int i;
int join_success = 0;
double deadline;
double next_stabilize_date = init_time + periodic_stabilize_delay;
double next_fix_fingers_date = init_time + periodic_fix_fingers_delay;
double next_check_predecessor_date = init_time + periodic_check_predecessor_delay;
double next_lookup_date = init_time + periodic_lookup_delay;
xbt_assert(argc == 3 || argc == 5, "Wrong number of arguments for this node");
// initialize my node
s_node_t node = {0};
node.id = xbt_str_parse_int(argv[1],"Invalid ID: %s");
get_mailbox(node.id, node.mailbox);
node.next_finger_to_fix = 0;
node.fingers = xbt_new0(s_finger_t, nb_bits);
node.last_change_date = init_time;
for (i = 0; i < nb_bits; i++) {
node.fingers[i].id = -1;
set_finger(&node, i, node.id);
}
if (argc == 3) { // first ring
deadline = xbt_str_parse_double(argv[2],"Invalid deadline: %s");
create(&node);
join_success = 1;
} else {
int known_id = xbt_str_parse_int(argv[2],"Invalid root ID: %s");
deadline = xbt_str_parse_double(argv[4],"Invalid deadline: %s");
XBT_DEBUG("Hey! Let's join the system.");
join_success = join(&node, known_id);
}
if (join_success) {
double now = MSG_get_clock();
int listen = 0;
int no_op = 0;
while (now < init_time + deadline && now < max_simulation_time) {
if (node.comm_receive == NULL) {
task_received = NULL;
node.comm_receive = MSG_task_irecv(&task_received, node.mailbox);
// FIXME: do not make MSG_task_irecv() calls from several functions
}
if (!MSG_comm_test(node.comm_receive)) { // no task was received: make some periodic calls
int sub_protocol = MC_random(0, 4);
if(MC_is_active() && !MC_visited_reduction() && no_op)
MC_cut();
if(listen == 0 && (sub_protocol > 0)){
if(sub_protocol == 1)
stabilize(&node);
else if(sub_protocol == 2)
fix_fingers(&node);
else if(sub_protocol == 3)
check_predecessor(&node);
else
random_lookup(&node);
listen = 1;
} else {
MSG_process_sleep(sleep_delay);
no_op = 1;
}
}else{
if (now >= next_stabilize_date) {
stabilize(&node);
next_stabilize_date = MSG_get_clock() + periodic_stabilize_delay;
}else if (now >= next_fix_fingers_date) {
fix_fingers(&node);
next_fix_fingers_date = MSG_get_clock() + periodic_fix_fingers_delay;
}else if (now >= next_check_predecessor_date) {
check_predecessor(&node);
next_check_predecessor_date = MSG_get_clock() + periodic_check_predecessor_delay;
}else if (now >= next_lookup_date) {
random_lookup(&node);
next_lookup_date = MSG_get_clock() + periodic_lookup_delay;
}else {
// nothing to do: sleep for a while
MSG_process_sleep(sleep_delay);
}
}
} else { // a transfer has occurred
msg_error_t status = MSG_comm_get_status(node.comm_receive);
MSG_comm_destroy(node.comm_receive);
node.comm_receive = NULL;
if (status == MSG_OK)
handle_task(&node, task_received);
else
XBT_DEBUG("Failed to receive a task. Nevermind.");
}
now = MSG_get_clock();
}
if (node.comm_receive) {
/* handle last task if any */
if (MSG_comm_wait(node.comm_receive, 0) == MSG_OK)
task_free(task_received);
MSG_comm_destroy(node.comm_receive);
node.comm_receive = NULL;
}
// leave the ring
leave(&node);
}
// stop the simulation
xbt_free(node.fingers);
return 0;
}
int main(int argc, char *argv[])
{
MSG_init(&argc, argv);
xbt_assert(argc > 2, "Usage: %s [-nb_bits=n] [-timeout=t] platform_file deployment_file\n"
"\tExample: %s ../msg_platform.xml chord.xml\n", argv[0], argv[0]);
char **options = &argv[1];
while (!strncmp(options[0], "-", 1)) {
int length = strlen("-nb_bits=");
if (!strncmp(options[0], "-nb_bits=", length) && strlen(options[0]) > length) {
nb_bits = xbt_str_parse_int(options[0] + length, "Invalid nb_bits parameter: %s");
XBT_DEBUG("Set nb_bits to %d", nb_bits);
} else {
length = strlen("-timeout=");
if (!strncmp(options[0], "-timeout=", length) && strlen(options[0]) > length) {
timeout = xbt_str_parse_int(options[0] + length, "Invalid timeout parameter: %s");
XBT_DEBUG("Set timeout to %d", timeout);
} else {
xbt_die("Invalid chord option '%s'", options[0]);
}
}
options++;
}
chord_initialize();
MSG_function_register("node", node);
XBT_INFO("Simulated time: %g", MSG_get_clock());
chord_exit();
return res != MSG_OK;
}