1 /***************** Centralized Mutual Exclusion Algorithm *********************/
2 /* This example implements a centralized mutual exclusion algorithm. */
3 /* Bug : CS requests of process 1 not satisfied */
4 /* LTL property checked : G(r->F(cs)); (r=request of CS, cs=CS ok) */
5 /******************************************************************************/
9 #include <simgrid/modelchecker.h>
26 int main(int argc, char **argv){
32 xbt_dynar_t requests = xbt_dynar_new(sizeof(int), NULL);
35 err = MPI_Init(&argc, &argv);
36 if(err != MPI_SUCCESS){
37 printf("MPI initialization failed !\n");
41 MC_automaton_new_propositional_symbol("r", &predR);
42 MC_automaton_new_propositional_symbol("cs", &predCS);
44 MC_ignore(&(status.count), sizeof(status.count));
46 /* Get number of processes */
47 err = MPI_Comm_size(MPI_COMM_WORLD, &size);
48 /* Get id of this process */
49 err = MPI_Comm_rank(MPI_COMM_WORLD, &rank);
51 if(rank == 0){ /* Coordinator */
53 MPI_Recv(&recv_buff, 1, MPI_INT, MPI_ANY_SOURCE, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
54 if(status.MPI_TAG == REQUEST_TAG){
56 printf("CS already used.\n");
57 xbt_dynar_push(requests, &recv_buff);
60 printf("CS idle. Grant immediatly.\n");
61 MPI_Send(&rank, 1, MPI_INT, recv_buff, GRANT_TAG, MPI_COMM_WORLD);
66 if(!xbt_dynar_is_empty(requests)){
67 printf("CS release. Grant to queued requests (queue size: %lu)", xbt_dynar_length(requests));
68 xbt_dynar_shift(requests, &recv_buff);
70 MPI_Send(&rank, 1, MPI_INT, recv_buff, GRANT_TAG, MPI_COMM_WORLD);
73 xbt_dynar_push(requests, &recv_buff);
77 printf("CS release. Resource now idle.\n");
84 printf("%d asks the request.\n", rank);
85 MPI_Send(&rank, 1, MPI_INT, 0, REQUEST_TAG, MPI_COMM_WORLD);
90 MPI_Recv(&recv_buff, 1, MPI_INT, 0, MPI_ANY_TAG, MPI_COMM_WORLD, &status);
91 if(status.MPI_TAG == GRANT_TAG && rank == 1){
95 printf("%d got the answer. Release it.\n", rank);
96 MPI_Send(&rank, 1, MPI_INT, 0, RELEASE_TAG, MPI_COMM_WORLD);