[MPICH] MPICH105 shm drops packages on SUN niagara

[chong tan]

The following code reproduces the problem.  I think you maybe able to reproduce the error on
Linux, but I am not sure.


It is best to run :
mpiexec -n 8 a.out
to reproduce the problem.  You will need a machine with 8CPU/cores.  SOmetime you will need to
run the code multiple time to see the error.

there will be files fast_mpi_?.dmp created, where ? is the rank of the related 'rank'.  When MPI get stuck,
you should look at the last line of fast_mpi_0.dmp.  If it says:

  read from child 7


then you should look at the last line of fast_mpi_7.dmp, it will say:
  read from master


hope this help to debug the error.

thanks
tan

---------------------
#include "stdlib.h"
#include "stdio.h"
#include "mpi.h"

#define LOOP_COUNT  1000000
#define DATA_SIZE   4
#define MP_TAG      999
main()
{
    int     nProc, rank ;
    int     argc = 0 ;
    int     i, j, status ;
    char    buf[ 128 ] ;
    FILE    *pf ;
    MPI_Init( &argc, NULL ) ;
    MPI_Comm_size( MPI_COMM_WORLD, &nProc ) ;
    MPI_Comm_rank( MPI_COMM_WORLD, &rank ) ;
    sprintf( buf, "fast_mpi_%d.dmp", rank ) ;
    pf = fopen( buf, "w" ) ;
    if( !rank ) {
       int      **psend ;
       int      **precv ;
       psend = (int**)calloc( nProc, sizeof( int *) ) ;
       precv = (int**)calloc( nProc, sizeof( int *) ) ;
       for( i = 0 ; i < nProc ; i++ ) {
           psend[ i ] = (int*)calloc( DATA_SIZE, sizeof( int ) ) ;
           precv[ i ] = (int*)calloc( DATA_SIZE, sizeof( int ) ) ;
       }
       for( i = 0 ; i < LOOP_COUNT ; i++ ) {
          fprintf( pf, "Master : loop %d\n", i ) ;
          fflush( pf ) ;
          for( j = 1 ; j < nProc ; j++ ) {
             fprintf( pf, "  read from child %d\n", j ) ;
             fflush( pf ) ;
             status = MPI_Recv( precv[ j ], DATA_SIZE, MPI_LONG, j, MP_TAG, MPI_COMM_WORLD, MP
I_STATUS_IGNORE ) ;
             fprintf( pf, "  read from child %d done, status = %d\n", j, status ) ;
             fflush( pf ) ;
          }
          for( j = 1 ; j < nProc ; j++ ) {
             fprintf( pf, "  send to child %d\n", j ) ;
             fflush( pf ) ;
             status = MPI_Send( psend[ j ], DATA_SIZE - 1, MPI_LONG, j, MP_TAG, MPI_COMM_WORLD
 ) ;
             fprintf( pf, "  send to child %d done, status = %d\n", j, status ) ;
             fflush( pf ) ;
          }
       }
    } else {
       int  *psend ;
       int  *precv ;
       psend = (int*)calloc( DATA_SIZE, sizeof( int ) ) ;
       precv = (int*)calloc( DATA_SIZE, sizeof( int ) ) ;
       for( i = 0 ; i < LOOP_COUNT ; i++ ) {
             fprintf( pf, "  send to master\n" ) ;
             fflush( pf ) ;
             status = MPI_Send( psend, DATA_SIZE - 1, MPI_LONG, 0, MP_TAG, MPI_COMM_WORLD ) ;
             fprintf( pf, "  send to master done, status = %d\n", status ) ;
             fflush( pf ) ;
             fprintf( pf, "  read from master\n" ) ;
             fflush( pf ) ;
             status = MPI_Recv( precv, DATA_SIZE, MPI_LONG, 0, MP_TAG, MPI_COMM_WORLD, MPI_STATUS_IGNORE ) ;
             fprintf( pf, "  read from master done, status = %d\n", status ) ;
             fflush( pf ) ;
       }
    }
    fclose( pf ) ;
    MPI_Finalize() ;
}

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