Hi all,

I ran many tests today. I saw that an older 4.0.2 version of OpenMPI
packaged with Nix was running using openib. So I add the --with-verbs
option to setup this module.

That I can see now is that:

mpirun -hostfile $OAR_NODEFILE *--mca mtl psm -mca btl_openib_allow_ib
true* ....

    - the testcase test_layout_array is running without error

    - the bandwidth measured with osu_bw is half of thar it should be:

        # OSU MPI Bandwidth Test v5.7
        # Size      Bandwidth (MB/s)
        1                       0.54
        2                       1.13
        4                       2.26
        8                       4.51
        16                      9.06
        32                     17.93
        64                     33.87
        128                    69.29
        256                   161.24
        512                   333.82
        1024                  682.66
        2048                 1188.63
        4096                 1760.14
        8192                 2166.08
        16384                2036.95
        32768                3466.63
        65536                6296.73
        131072               7509.43
        262144               9104.78
        524288               6908.55
        1048576              5530.37
        2097152              4489.16
        4194304              3498.14

mpirun -hostfile $OAR_NODEFILE *--mca mtl psm2 -mca btl_openib_allow_ib
true* ...

    - the testcase test_layout_array is not giving correct results

    - the bandwidth measured with osu_bw is the right one:

        # OSU MPI Bandwidth Test v5.7
        # Size      Bandwidth (MB/s)
        1                       3.73
        2                       7.96
        4                      15.82
        8                      31.22
        16                     51.52
        32                    107.61
        64                    196.51
        128                   438.66
        256                   817.70
        512                  1593.90
        1024                 2786.09
        2048                 4459.77
        4096                 6658.70
        8192                 8092.95
        16384                8664.43
        32768                8495.96
        65536               11458.77
        131072              12094.64
        262144              11781.84
        524288              12297.58
        1048576             12346.92
        2097152             12206.53
        4194304             12167.00

But yes, I know openib is deprecated too in 4.0.5.

Patrick

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