I can only assume you tested a particular implementation of MPI-3, since the MPI standard itself does not execute on any platform of which I know. Can I assume you have identified bugs or semantic misinterpretations present in CrayMPI, which is a derivative of MPICH? If so, I recommend replacing the MPI-3 RMA working group with the Cray and MPICH developers. Best, Jeff On Tue, Feb 4, 2014 at 10:03 AM, Rolf Rabenseifner <[email protected]> wrote:

Dear all,

I tested MPI-3.0 1-sided synchronization on shared memory windows. A lot didn't worked as I expected:

- assertions fail with MPI_Win_fence (there is no restriction defined on MPI-3.0 p452:8-19),

- Post-Start-Complete-Wait fully fails (compare MPI-3.0 p410:16-19, especially the ref to Sect.11.5),

- and MPI_Free_mem also fails for the shared memory windows (compare MI-3.0 p409:23-24, especially that MPI_FREE_MEM is mentioned here).

Attached are some files: - halo_1sided_put_win_alloc_20.f90

This is the basis and works. It is with normal (distributed) windows.

- halo_1sided_put_win_alloc_shared_20.f90

It is the first shared memory example. It causes several errors with the test on our Cray system: - The assertions on MPI_WIN_FENCE do not work - The MPI_FREE_MEM does not work for the shared buffers

Is my program wrong? it is a simple left and right 1-dim halo exchange.

- halo_1sided_put_win_alloc_shared_20_w-a-cray.f90

This is a workaround that works on our Cray: - assertions MPI_MODE_NOPRECEDE and MPI_MODE_NOSUCCEED removed - MPI_FREE_MEM removed

- halo_1sided_put_win_alloc_shared_pscw_20.f90

With Post-Start-Complete-Wait, nothing works! No work-around.

- halo_1sided_put_win_alloc_shared_othersync_20.f90

In this example, I fully substituted the RMA synchronization by point-to-point synchronization with Irecv, send and waitall. Is this allowed? Was it intended? Is there any wording about in MPI-3.0? Will we have any wording in MPI-next? (3.1 or 4.0)?

I hope, someone knows the answers.

Best regards Rolf

-- Dr. Rolf Rabenseifner . . . . . . . . . .. email [email protected] High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530 University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832 Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room 1.307)

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