1 /* Copyright (c) 2013-2014. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
7 /***************** Centralized Mutual Exclusion Algorithm *********************/
8 /* This example implements a centralized mutual exclusion algorithm. */
9 /* Bug : CS requests of process 1 not satisfied */
10 /* LTL property checked : G(r->F(cs)); (r=request of CS, cs=CS ok) */
11 /******************************************************************************/
15 #include <simgrid/modelchecker.h>
32 int main(int argc, char **argv){
38 xbt_dynar_t requests = xbt_dynar_new(sizeof(int), NULL);
41 err = MPI_Init(&argc, &argv);
42 if(err != MPI_SUCCESS){
43 printf("MPI initialization failed !\n");
47 MC_automaton_new_propositional_symbol("r", &predR);
48 MC_automaton_new_propositional_symbol("cs", &predCS);
50 MC_ignore(&(status.count), sizeof(status.count));
52 /* Get number of processes */
53 err = MPI_Comm_size(MPI_COMM_WORLD, &size);
54 /* Get id of this process */
55 err = MPI_Comm_rank(MPI_COMM_WORLD, &rank);
57 if(rank == 0){ /* Coordinator */
59 MPI_Recv(&recv_buff, 1, MPI_INT, MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
60 if(status.MPI_TAG == REQUEST_TAG){
62 printf("CS already used.\n");
63 xbt_dynar_push(requests, &recv_buff);
65 if(recv_buff != size - 1){
66 printf("CS idle. Grant immediatly.\n");
67 MPI_Send(&rank, 1, MPI_INT, recv_buff, GRANT_TAG, MPI_COMM_WORLD);
72 if(!xbt_dynar_is_empty(requests)){
73 printf("CS release. Grant to queued requests (queue size: %lu)", xbt_dynar_length(requests));
74 xbt_dynar_shift(requests, &recv_buff);
75 if(recv_buff != size - 1){
76 MPI_Send(&rank, 1, MPI_INT, recv_buff, GRANT_TAG, MPI_COMM_WORLD);
79 xbt_dynar_push(requests, &recv_buff);
83 printf("CS release. Resource now idle.\n");
90 printf("%d asks the request.\n", rank);
91 MPI_Send(&rank, 1, MPI_INT, 0, REQUEST_TAG, MPI_COMM_WORLD);
96 MPI_Recv(&recv_buff, 1, MPI_INT, 0, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
97 if(status.MPI_TAG == GRANT_TAG && rank == size - 1){
101 printf("%d got the answer. Release it.\n", rank);
102 MPI_Send(&rank, 1, MPI_INT, 0, RELEASE_TAG, MPI_COMM_WORLD);
103 if(rank == size - 1){