> MPI_Exscan(&b, &offset, 1, MPI_INT, MPI_SUM,MPI_COMM_WORLD);
Your offset is of type MPI_Offset, an 8-byte integer.
Variable b is of type int, a 4-byte integer.
Please try change the data type for b to MPI_Offset and use
MPI_Exscan(&b, &offset, 1, MPI_OFFSET, MPI_SUM,MPI_COMM_WORLD);
Wei-keng
On Jul 8, 2013, at 10:58 AM, Yves Revaz wrote:
> Dear List,
>
> I'm facing a problem with the mpi-io on pvfs.
> I'm using orangefs-2.8.7 on 6 server nodes.
>
> I recently tried to play with mpi-io as pvfs is designed to
> support parallel access to a single file.
>
> I used the following simple code (see below) where different processes open a
> file
> and write each at a different position in the file.
>
> I compiled it with mpich2, as pvfs seems to only support this version to use
> the
> parallel access facilities, right ?
>
> When running my test code on a classical file system, the code works
> perfectly and I get the following output:
>
> mpirun -n 4 ./a.out
> PE03: write at offset = 30
> PE03: write count = 10
> PE00: write at offset = 0
> PE00: write count = 10
> PE01: write at offset = 10
> PE01: write count = 10
> PE02: write at offset = 20
> PE02: write count = 10
>
> as expected a file "testfile" is created.
> However, the same code acessing my pvfs file system gives:
>
> mpirun -n 4 ./a.out
> PE00: write at offset = 0
> PE00: write count = -68457862
> PE02: write at offset = 20
> PE02: write count = 32951150
> PE01: write at offset = 10
> PE01: write count = -110085322
> PE03: write at offset = 30
> PE03: write count = -268114218
>
> and no file "testfile" is created.
>
> I'm I doing something wrong ? Do I need to compile orangefs or mpich2 with
> particular options ?
>
> Thanks for your precious help,
>
> yves
>
>
>
> My simple code:
> ---------------------
>
> #include "mpi.h"
> #include <stdio.h>
> #define BUFSIZE 10
>
> int main(int argc, char *argv[])
> {
> int i, me, buf[BUFSIZE];
> int b, offset, count;
> MPI_File myfile;
> MPI_Offset disp;
> MPI_Status stat;
>
> MPI_Init(&argc, &argv);
> MPI_Comm_rank(MPI_COMM_WORLD, &me);
> for (i=0; i<BUFSIZE; i++)
> buf[i] = me*BUFSIZE + i;
>
> MPI_File_open(MPI_COMM_WORLD, "testfile", MPI_MODE_WRONLY |
> MPI_MODE_CREATE,
> MPI_INFO_NULL, &myfile);
>
> offset = 0;
> b = BUFSIZE;
> MPI_Exscan(&b, &offset, 1, MPI_INT, MPI_SUM,MPI_COMM_WORLD);
> disp = offset*sizeof(int);
> printf("PE%2.2i: write at offset = %d\n", me, offset);
>
> MPI_File_set_view(myfile, disp,
> MPI_INT, MPI_INT, "native", MPI_INFO_NULL);
> MPI_File_write(myfile, buf, BUFSIZE, MPI_INT,
> &stat);
> MPI_Get_count(&stat, MPI_INT, &count);
> printf("PE%2.2i: write count = %d\n", me, count);
> MPI_File_close(&myfile);
>
> MPI_Finalize();
>
> return 0;
> }
>
>
>
>
>
>
>
>
>
>
>
>
>
> --
>
> ---------------------------------------------------------------------
> Dr. Yves Revaz
> Laboratory of Astrophysics
> Ecole Polytechnique Fédérale de Lausanne (EPFL)
> Observatoire de Sauverny Tel : +41 22 379 24 28
> 51. Ch. des Maillettes Fax : +41 22 379 22 05
> 1290 Sauverny e-mail :
> [email protected]
>
> SWITZERLAND Web :
> http://people.epfl.ch/yves.revaz
>
> ---------------------------------------------------------------------
>
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