Patrick how are you using original PSM if you’re using Omni-Path hardware? The original PSM was written for QLogic DDR and QDR Infiniband adapters.
As far as needing openib - the issue is that the PSM2 MTL doesn’t support a subset of MPI operations that we previously used the pt2pt BTL for. For recent version of OMPI, the preferred BTL to use with PSM2 is OFI. Is there any chance you can give us a sample MPI app that reproduces the problem? I can’t think of another way I can give you more help without being able to see what’s going on. It’s always possible there’s a bug in the PSM2 MTL but it would be surprising at this point. Sent from my iPad On Jan 26, 2021, at 1:13 PM, Patrick Begou via users <users@lists.open-mpi.org> wrote: 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
