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/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */
/*
* (C) 2001 by Argonne National Laboratory.
* See COPYRIGHT in top-level directory.
*/
#include "mpi.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
/* A simple performance test. The file name is taken as a
command-line argument. */
#define SIZE (1048576*4) /* read/write size per node in bytes */
int main(int argc, char **argv)
{
int *buf, i, j, mynod, nprocs, ntimes=5, len, err, flag;
double stim, read_tim, write_tim, new_read_tim, new_write_tim;
double min_read_tim=10000000.0, min_write_tim=10000000.0, read_bw, write_bw;
MPI_File fh;
MPI_Status status;
char *filename;
MPI_Init(&argc,&argv);
MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
MPI_Comm_rank(MPI_COMM_WORLD, &mynod);
/* process 0 takes the file name as a command-line argument and
broadcasts it to other processes */
if (!mynod) {
i = 1;
while ((i < argc) && strcmp("-fname", *argv)) {
i++;
argv++;
}
if (i >= argc) {
fprintf(stderr, "\n*# Usage: perf -fname filename\n\n");
MPI_Abort(MPI_COMM_WORLD, 1);
}
argv++;
len = strlen(*argv);
filename = (char *) malloc(len+1);
strcpy(filename, *argv);
MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);
MPI_Bcast(filename, len+1, MPI_CHAR, 0, MPI_COMM_WORLD);
fprintf(stderr, "Access size per process = %d bytes, ntimes = %d\n", SIZE, ntimes);
}
else {
MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);
filename = (char *) malloc(len+1);
MPI_Bcast(filename, len+1, MPI_CHAR, 0, MPI_COMM_WORLD);
}
buf = (int *) malloc(SIZE);
for (j=0; j<ntimes; j++) {
MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_CREATE |
MPI_MODE_RDWR, MPI_INFO_NULL, &fh);
MPI_File_seek(fh, mynod*SIZE, MPI_SEEK_SET);
MPI_Barrier(MPI_COMM_WORLD);
stim = MPI_Wtime();
MPI_File_write(fh, buf, SIZE, MPI_BYTE, &status);
write_tim = MPI_Wtime() - stim;
MPI_File_close(&fh);
MPI_Barrier(MPI_COMM_WORLD);
MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_CREATE |
MPI_MODE_RDWR, MPI_INFO_NULL, &fh);
MPI_File_seek(fh, mynod*SIZE, MPI_SEEK_SET);
MPI_Barrier(MPI_COMM_WORLD);
stim = MPI_Wtime();
MPI_File_read(fh, buf, SIZE, MPI_BYTE, &status);
read_tim = MPI_Wtime() - stim;
MPI_File_close(&fh);
MPI_Allreduce(&write_tim, &new_write_tim, 1, MPI_DOUBLE, MPI_MAX,
MPI_COMM_WORLD);
MPI_Allreduce(&read_tim, &new_read_tim, 1, MPI_DOUBLE, MPI_MAX,
MPI_COMM_WORLD);
min_read_tim = (new_read_tim < min_read_tim) ?
new_read_tim : min_read_tim;
min_write_tim = (new_write_tim < min_write_tim) ?
new_write_tim : min_write_tim;
}
if (mynod == 0) {
read_bw = (SIZE*nprocs)/(min_read_tim*1024.0*1024.0);
write_bw = (SIZE*nprocs)/(min_write_tim*1024.0*1024.0);
fprintf(stderr, "Write bandwidth without file sync = %f Mbytes/sec\n", write_bw);
fprintf(stderr, "Read bandwidth without prior file sync = %f Mbytes/sec\n", read_bw);
}
min_write_tim=10000000.0;
min_read_tim=10000000.0;
flag = 0;
for (j=0; j<ntimes; j++) {
MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_CREATE |
MPI_MODE_RDWR, MPI_INFO_NULL, &fh);
MPI_File_seek(fh, mynod*SIZE, MPI_SEEK_SET);
MPI_Barrier(MPI_COMM_WORLD);
stim = MPI_Wtime();
MPI_File_write(fh, buf, SIZE, MPI_BYTE, &status);
err = MPI_File_sync(fh);
write_tim = MPI_Wtime() - stim;
if (err == MPI_ERR_UNKNOWN) {
flag = 1;
break;
}
MPI_File_close(&fh);
MPI_Barrier(MPI_COMM_WORLD);
MPI_File_open(MPI_COMM_WORLD, filename, MPI_MODE_CREATE |
MPI_MODE_RDWR, MPI_INFO_NULL, &fh);
MPI_File_seek(fh, mynod*SIZE, MPI_SEEK_SET);
MPI_Barrier(MPI_COMM_WORLD);
stim = MPI_Wtime();
MPI_File_read(fh, buf, SIZE, MPI_BYTE, &status);
read_tim = MPI_Wtime() - stim;
MPI_File_close(&fh);
MPI_Allreduce(&write_tim, &new_write_tim, 1, MPI_DOUBLE, MPI_MAX,
MPI_COMM_WORLD);
MPI_Allreduce(&read_tim, &new_read_tim, 1, MPI_DOUBLE, MPI_MAX,
MPI_COMM_WORLD);
min_read_tim = (new_read_tim < min_read_tim) ?
new_read_tim : min_read_tim;
min_write_tim = (new_write_tim < min_write_tim) ?
new_write_tim : min_write_tim;
}
if (mynod == 0) {
if (flag) fprintf(stderr, "MPI_File_sync returns error.\n");
else {
read_bw = (SIZE*nprocs)/(min_read_tim*1024.0*1024.0);
write_bw = (SIZE*nprocs)/(min_write_tim*1024.0*1024.0);
fprintf(stderr, "Write bandwidth including file sync = %f Mbytes/sec\n", write_bw);
fprintf(stderr, "Read bandwidth after file sync = %f Mbytes/sec\n", read_bw);
}
}
free(buf);
free(filename);
MPI_Finalize();
return 0;
}
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