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/*
* Copyright (C) by Argonne National Laboratory
* See COPYRIGHT in top-level directory
*/
#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>
#include "mpitest.h"
#define MAX_LOG_WSIZE 31
#define MAX_LOOP 20
int main(int argc, char *argv[])
{
MPI_Group gworld, g;
MPI_Comm comm, newcomm[MAX_LOOP];
int wsize, wrank, range[1][3], errs = 0;
double t[MAX_LOG_WSIZE], tf;
int maxi, i, k, ts, gsize[MAX_LOG_WSIZE];
MTest_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &wsize);
MPI_Comm_rank(MPI_COMM_WORLD, &wrank);
if (wrank == 0)
MTestPrintfMsg(1, "size\ttime\n");
MPI_Comm_group(MPI_COMM_WORLD, &gworld);
ts = 1;
comm = MPI_COMM_WORLD;
for (i = 0; ts <= wsize; i++, ts = ts + ts) {
/* Create some groups with at most ts members */
range[0][0] = ts - 1;
range[0][1] = 0;
range[0][2] = -1;
MPI_Group_range_incl(gworld, 1, range, &g);
MPI_Barrier(MPI_COMM_WORLD);
tf = MPI_Wtime();
for (k = 0; k < MAX_LOOP; k++)
MPI_Comm_create(comm, g, &newcomm[k]);
tf = MPI_Wtime() - tf;
MPI_Allreduce(&tf, &t[i], 1, MPI_DOUBLE, MPI_MAX, MPI_COMM_WORLD);
t[i] = t[i] / MAX_LOOP;
gsize[i] = ts;
if (wrank == 0)
MTestPrintfMsg(1, "%d\t%e\n", ts, t[i]);
MPI_Group_free(&g);
if (newcomm[0] != MPI_COMM_NULL)
for (k = 0; k < MAX_LOOP; k++)
MPI_Comm_free(&newcomm[k]);
}
MPI_Group_free(&gworld);
maxi = i - 1;
/* The cost should be linear or at worst ts*log(ts).
* We can check this in a number of ways.
*/
if (wrank == 0) {
for (i = 4; i <= maxi; i++) {
double rdiff;
if (t[i] > 0) {
rdiff = (t[i] - t[i - 1]) / t[i];
if (rdiff >= 4) {
errs++;
fprintf(stderr,
"Relative difference between group of size %d and %d is %e exceeds 4\n",
gsize[i - 1], gsize[i], rdiff);
}
}
}
}
MTest_Finalize(errs);
return MTestReturnValue(errs);
}
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