6 #define BUFSIZE (1024 * 1024)
7 #define BOUNDED(sz) ((sz) < BUFSIZE ? (sz) : BUFSIZE)
9 static void setup_recvbuf(int nprocs, int** recvbuf, int** displs, int** counts, int** rcounts)
11 *recvbuf = malloc(BUFSIZE * nprocs * sizeof(int));
12 assert(*recvbuf != NULL);
13 for (int i = 0; i < BUFSIZE * nprocs; i++)
16 *displs = malloc(nprocs * sizeof(int));
17 *counts = malloc(nprocs * sizeof(int));
18 *rcounts = malloc(nprocs * sizeof(int));
19 for (int i = 0; i < nprocs; i++) {
20 (*displs)[i] = i * BUFSIZE;
21 (*counts)[i] = BOUNDED(i);
22 (*rcounts)[i] = (*counts)[i];
26 int main(int argc, char** argv)
32 MPI_Init(&argc, &argv);
33 MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
34 MPI_Comm_rank(MPI_COMM_WORLD, &rank);
36 int* sendbuf = malloc(BUFSIZE * nprocs * sizeof(int));
37 for (int i = 0; i < BUFSIZE * nprocs; i++)
40 int* alltoallvcounts = malloc(nprocs * sizeof(int));
41 for (int i = 0; i < nprocs; i++)
42 alltoallvcounts[i] = BOUNDED(i + rank);
44 int* dummy_buffer = malloc(sizeof(int));
45 // initialize buffers with an invalid value (we want to trigger a valgrind error if they are used)
46 int* recvbuf = dummy_buffer + 1;
47 int* displs = dummy_buffer + 1;
48 int* counts = dummy_buffer + 1;
49 int* rcounts = dummy_buffer + 1;
51 setup_recvbuf(nprocs, &recvbuf, &displs, &counts, &rcounts);
53 // first test, with unallocated non significative buffers
54 MPI_Barrier(MPI_COMM_WORLD);
55 MPI_Bcast(sendbuf, BUFSIZE, MPI_INT, 0, MPI_COMM_WORLD);
56 MPI_Gather(&sendbuf[rank * BUFSIZE], BUFSIZE, MPI_INT, recvbuf, BUFSIZE, MPI_INT, 0, MPI_COMM_WORLD);
57 MPI_Scatter(recvbuf, BUFSIZE, MPI_INT, sendbuf, BUFSIZE, MPI_INT, 0, MPI_COMM_WORLD);
58 MPI_Gatherv(&sendbuf[rank * BUFSIZE], BOUNDED(rank), MPI_INT, recvbuf, rcounts, displs, MPI_INT, 0, MPI_COMM_WORLD);
59 MPI_Scatterv(recvbuf, counts, displs, MPI_INT, sendbuf, BOUNDED(rank), MPI_INT, 0, MPI_COMM_WORLD);
60 MPI_Reduce(sendbuf, recvbuf, BUFSIZE, MPI_INT, MPI_MAX, 0, MPI_COMM_WORLD);
64 setup_recvbuf(nprocs, &recvbuf, &displs, &counts, &rcounts);
66 MPI_Barrier(MPI_COMM_WORLD);
67 MPI_Bcast(sendbuf, BUFSIZE, MPI_INT, 0, MPI_COMM_WORLD);
68 MPI_Gather(&sendbuf[rank * BUFSIZE], BUFSIZE, MPI_INT, recvbuf, BUFSIZE, MPI_INT, 0, MPI_COMM_WORLD);
69 MPI_Scatter(recvbuf, BUFSIZE, MPI_INT, sendbuf, BUFSIZE, MPI_INT, 0, MPI_COMM_WORLD);
70 MPI_Gatherv(&sendbuf[rank * BUFSIZE], BOUNDED(rank), MPI_INT, recvbuf, rcounts, displs, MPI_INT, 0, MPI_COMM_WORLD);
71 MPI_Scatterv(recvbuf, counts, displs, MPI_INT, sendbuf, BOUNDED(rank), MPI_INT, 0, MPI_COMM_WORLD);
72 MPI_Reduce(sendbuf, recvbuf, BUFSIZE, MPI_INT, MPI_MAX, 0, MPI_COMM_WORLD);
73 MPI_Allgather(sendbuf, BUFSIZE, MPI_INT, recvbuf, BUFSIZE, MPI_INT, MPI_COMM_WORLD);
74 MPI_Alltoall(recvbuf, BUFSIZE, MPI_INT, sendbuf, BUFSIZE, MPI_INT, MPI_COMM_WORLD);
75 MPI_Allgatherv(sendbuf, BOUNDED(rank), MPI_INT, recvbuf, rcounts, displs, MPI_INT, MPI_COMM_WORLD);
76 MPI_Alltoallv(recvbuf, alltoallvcounts, displs, MPI_INT, sendbuf, alltoallvcounts, displs, MPI_INT, MPI_COMM_WORLD);
77 MPI_Allreduce(sendbuf, recvbuf, BUFSIZE, MPI_INT, MPI_MAX, MPI_COMM_WORLD);
78 MPI_Reduce_scatter(sendbuf, recvbuf, rcounts, MPI_INT, MPI_MAX, MPI_COMM_WORLD);
79 MPI_Scan(sendbuf, recvbuf, BUFSIZE, MPI_INT, MPI_MAX, MPI_COMM_WORLD);
80 MPI_Exscan(sendbuf, recvbuf, BUFSIZE, MPI_INT, MPI_MAX, MPI_COMM_WORLD);
81 MPI_Barrier(MPI_COMM_WORLD);
83 free(alltoallvcounts);