[Mitgcm-support] Re: MPI with ifc broken ?

[mitgcm-support at dev.mitgcm.org]

Alistair,

Dimitris is at a conference this week.
I had trouble too setting up the parallel global state estimation
on an AER cluster, maybe the same problem.
Can we fix it here?

-p.

support at mitgcm.org wrote:
> Dimitri,
> 
> Hate to complain BUT...
> 
> The stuff you added to ini_procs.F (for gather/scatter) seems to be breaking
> the parallel version of the model.
> 
> Looking at what you've done, you're using blocking sends without
> corresponding receives so that the model can't get past those sends.  I
> think you need non-blocking sends followed by receives. Can you undo those
> changes prompto and then fix it.
> 
> Thanks,
> 
> A.
> 
> 
>>-----Original Message-----
>>From: Jean-Michel Campin [mailto:jmc at gulf.mit.edu]
>>Sent: Friday, May 09, 2003 10:04 AM
>>To: support at mitgcm.org
>>Subject: Re: MPI with ifc broken ?
>>
>>
>>Hi again,
>>
>>
>>>It seems that something is broken in the code
>>>for MPI with ifc (Linux, like the myrinet-3 cluster) between 
>>>checkpoint48e (still working) and checkpoint48f: no output (all 
>>>STDOUT + STDERR are empty) and the error message is (on 2 cpus):
>>
>>Finally it turns to be weekly related to modifications
>>for scatter_2d.F gather_2d.F : the problem is in
>>ini_procs.F (eesup/src) and is due to the changes between
>>1.14 and 1.15:
>>
>>
>>>C--   To speed-up mpi gather and scatter routines, myXGlobalLo
>>>C     and myYGlobalLo from each process are transferred to
>>>C     a common block array.  This allows process 0 to know
>>>C     the location of the domains controlled by each process.
>>>       DO npe = 0, numberOfProcs-1
>>>          CALL MPI_SEND (myXGlobalLo, 1, MPI_INTEGER,
>>>     &         npe, mpiMyId, MPI_COMM_MODEL, ierr)
>>>       ENDDO
>>>       DO npe = 0, numberOfProcs-1
>>>          CALL MPI_RECV (itemp, 1, MPI_INTEGER,
>>>     &         npe, npe, MPI_COMM_MODEL, istatus, ierr)
>>>          mpi_myXGlobalLo(npe+1) = itemp
>>>       ENDDO
>>>       DO npe = 0, numberOfProcs-1
>>>          CALL MPI_SEND (myYGlobalLo, 1, MPI_INTEGER,
>>>     &         npe, mpiMyId, MPI_COMM_MODEL, ierr)
>>>       ENDDO
>>>       DO npe = 0, numberOfProcs-1
>>>          CALL MPI_RECV (itemp, 1, MPI_INTEGER,
>>>     &         npe, npe, MPI_COMM_MODEL, istatus, ierr)
>>>          mpi_myYGlobalLo(npe+1) = itemp
>>>       ENDDO   
>>
>>When I comment those lines, it works fine.
>>
>>Jean_Michel
> 
> 
> 


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