[mvapich-discuss] MPI-IO Inconsistency over Lustre using MVAPICH

Nathan Baca nathan.baca at gmail.com
Tue Mar 3 22:45:16 EST 2009


Hello,

I am seeing inconsistent mpi-io behavior when writing to a Lustre file
system using mvapich2 1.2p1 and mvapich 1.1 both with romio. What follows is
a simple reproducer and output. Essentially one or more of the running
processes does not read or write the correct amount of data to its part of a
file residing on a Lustre (parallel) file system.

I have tried both isolating the output to a single OST and striping across
multiple OSTs. Both will reproduce the same result. I have tried compiling
with multiple versions of both pathscale and intel compilers all with the
same result.

The odd thing is that this seems to work using hpmpi 2.03 with pathscale 3.2
and intel 10.1.018. The operating system is XC 3.2.1 which is essentially
rhel4.5. The kernel is 2.6.9-67.9hp.7sp.XCsmp. Lustre version is
lustre-1.4.11-2.3_0.6_xc3.2.1_k2.6.9_67.9hp.7sp.XCsmp.

Any help figuring out what is happening is greatly appreciated. Thanks, Nate

program gcrm_test_io
  implicit none
  include "mpif.h"

  integer X_SIZE

      integer w_me, w_nprocs
      integer  my_info

      integer i
      integer (kind=4) :: ierr
      integer (kind=4) :: fileID

      integer (kind=MPI_OFFSET_KIND)        :: mylen
      integer (kind=MPI_OFFSET_KIND)        :: offset
      integer status(MPI_STATUS_SIZE)
      integer count
      integer ncells
      real (kind=4), allocatable, dimension (:)     :: array2
      logical sync

      call mpi_init(ierr)
      call MPI_COMM_SIZE(MPI_COMM_WORLD,w_nprocs,ierr)
      call MPI_COMM_RANK(MPI_COMM_WORLD,w_me,ierr)

      call mpi_info_create(my_info, ierr)
!     optional ways to set things in mpi-io
!     call mpi_info_set   (my_info, "romio_ds_read" , "enable"   , ierr)
!     call mpi_info_set   (my_info, "romio_ds_write", "enable"   , ierr)
!     call mpi_info_set   (my_info, "romio_cb_write", "enable"    , ierr)

      x_size = 410011  ! A 'big' number, with bigger numbers it is more
likely to fail
      sync = .true.  ! Extra file synchronization

      ncells = (X_SIZE * w_nprocs)

!  Use node zero to fill it with nines
      if (w_me .eq. 0) then
          call MPI_FILE_OPEN  (MPI_COMM_SELF, "output.dat",
MPI_MODE_CREATE+MPI_MODE_WRONLY, my_info, fileID, ierr)
          allocate (array2(ncells))
          array2(:) = 9.0
          mylen = ncells
          offset = 0 * 4
          call MPI_FILE_SET_VIEW(fileID,offset, MPI_REAL,MPI_REAL,
"native",MPI_INFO_NULL,ierr)
          call MPI_File_write(fileID, array2, mylen , MPI_REAL, status,ierr)

          call MPI_Get_count(status,MPI_INTEGER, count, ierr)
          if (count .ne. mylen) print*, "Wrong initial write count:",
count,mylen
          deallocate(array2)
          if (sync) call MPI_FILE_SYNC (fileID,ierr)
          call MPI_FILE_CLOSE (fileID,ierr)
      endif

!  All nodes now fill their area with ones
      call MPI_BARRIER(MPI_COMM_WORLD,ierr)
      allocate (array2( X_SIZE))
      array2(:) = 1.0
      offset = (w_me * X_SIZE) * 4 ! multiply by four, since it is real*4
      mylen = X_SIZE
      call MPI_FILE_OPEN  (MPI_COMM_WORLD,"output.dat",MPI_MODE_WRONLY,
my_info, fileID, ierr)
      print*,"node",w_me,"starting",(offset/4) + 1,"ending",(offset/4)+mylen

      call MPI_FILE_SET_VIEW(fileID,offset, MPI_REAL,MPI_REAL,
"native",MPI_INFO_NULL,ierr)
      call MPI_File_write(fileID, array2, mylen , MPI_REAL, status,ierr)
      call MPI_Get_count(status,MPI_INTEGER, count, ierr)
      if (count .ne. mylen) print*, "Wrong write count:", count,mylen,w_me
      deallocate(array2)
      if (sync) call MPI_FILE_SYNC (fileID,ierr)
      call MPI_FILE_CLOSE (fileID,ierr)

!  Read it back on node zero to see if it is ok data
      if (w_me .eq. 0) then
          call MPI_FILE_OPEN  (MPI_COMM_SELF, "output.dat", MPI_MODE_RDONLY,
my_info, fileID, ierr)
          mylen = ncells
          allocate (array2(ncells))
          call MPI_File_read(fileID, array2, mylen , MPI_REAL, status,ierr)
          call MPI_Get_count(status,MPI_INTEGER, count, ierr)
          if (count .ne. mylen) print*, "Wrong read count:", count,mylen
          do i=1,ncells
               if (array2(i) .ne. 1) then
                  print*, "ERROR", i,array2(i), ((i-1)*4),
((i-1)*4)/(1024d0*1024d0) ! Index, value, # of good bytes,MB
                  goto 999
               end if
          end do
          print*, "All done with nothing wrong"
 999      deallocate(array2)
          call MPI_FILE_CLOSE (fileID,ierr)
          call MPI_file_delete ("output.dat",MPI_INFO_NULL,ierr)
      endif

      call mpi_finalize(ierr)

end program gcrm_test_io

1.2p1 MVAPICH 2
 node 1 starting 410012 ending 820022
 node 2 starting 820023 ending 1230033
 node 3 starting 1230034 ending 1640044
 node 4 starting 1640045 ending 2050055
 node 5 starting 2050056 ending 2460066
 node 0 starting 1 ending 410011
 All done with nothing wrong


 node 1 starting 410012 ending 820022
 node 4 starting 1640045 ending 2050055
 node 3 starting 1230034 ending 1640044
 node 5 starting 2050056 ending 2460066
 node 2 starting 820023 ending 1230033
 Wrong write count: 228554 410011 2
 node 0 starting 1 ending 410011
 Wrong read count: 1048576 2460066
 ERROR 1048577 0.E+0 4194304 4.


 node 1 starting 410012 ending 820022
 node 3 starting 1230034 ending 1640044
 node 4 starting 1640045 ending 2050055
 node 2 starting 820023 ending 1230033
 node 5 starting 2050056 ending 2460066
 node 0 starting 1 ending 410011
 Wrong read count: 1048576 2460066
 ERROR 1048577 0.E+0 4194304 4.


1.1 MVAPICH
 node           0 starting                     1 ending
410011
 node           4 starting               1640045 ending
2050055
 node           3 starting               1230034 ending
1640044
 node           2 starting                820023 ending
1230033
 node           1 starting                410012 ending
820022
 node           5 starting               2050056 ending
2460066
 All done with nothing wrong


 node           0 starting                     1 ending
410011
 node           5 starting               2050056 ending
2460066
 node           2 starting                820023 ending
1230033
 node           1 starting                410012 ending
820022
 Wrong write count:      228554                410011           2
 node           3 starting               1230034 ending
1640044
 node           4 starting               1640045 ending
2050055
 Wrong read count:     1048576               2460066
 ERROR     1048577  0.0000000E+00     4194304   4.00000000000000


 node           0 starting                     1 ending
410011
 node           3 starting               1230034 ending
1640044
 node           4 starting               1640045 ending
2050055
 node           1 starting                410012 ending
820022
 node           5 starting               2050056 ending
2460066
 node           2 starting                820023 ending
1230033
 Wrong read count:     1229824               2460066
 ERROR     1229825  0.0000000E+00     4919296   4.69140625000000


-- 
Nathan Baca
nathan.baca at gmail.com
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