We may not need to use openmpi with Infiniband if we can get similar performance running psana2 on Ethernet for MPI communications. This connections are needed only for transferring small data (11 GB) for this test from Smd0 to EventBuilders and BigData nodes. Here we show the performance of reading 123 GB on 16 files using 7 drp nodes (113 cores: 1 Smd0/ 12 EventBuilders/ 100 Bigdata cores).
Conclusion:
Using OpenMPI with Infiniband: Rate 39.5 kHz (Total Time: 253 s)
Using MPICH from conda on Ethernet: Rate 39.7 kHz (Total Time: 252 s)
Note 1: below are plots from Grafana showing incoming/outgoing traffics
OpenMPI with Infiniband: the outgoing traffic peaks show Smd0 sending chunks of data to EventBuilders over Infiniband.
MPICH on Ethernet: no noticeable peaks
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