Libfabric support multiple providers. Sounds like it was selecting the sockets or tcp provider rather than a provider that support RoCE. I am not exactly sure whether the verbs provider will do that. If you can confirm the provider using libfabric tests, then you can try forcing MPICH to use that provider by setting the FI_PROVIDER environment variable. -- Hui Zhou From: Niyaz Murshed via discuss <[email protected]> Date: Wednesday, June 12, 2024 at 9:03 AM To: [email protected] <[email protected]> Cc: Niyaz Murshed <[email protected]>, nd <[email protected]> Subject: [mpich-discuss] Mpich over RDMA sample Hello, I am trying to learn about MPICH and its performance over RDMA. I am using libfabric and installed mpich using the below configure. ./configure --prefix=/opt/mpich/ --with-ofi=/opt/libfabric/ When I run any applications between 2 directly ZjQcmQRYFpfptBannerStart This Message Is From an External Sender This message came from outside your organization. ZjQcmQRYFpfptBannerEnd Hello, I am trying to learn about MPICH and its performance over RDMA. I am using libfabric and installed mpich using the below configure. ./configure --prefix=/opt/mpich/ --with-ofi=/opt/libfabric/ When I run any applications between 2 directly connected servers having Mellanox NICs, I see that communication is happening over tcp and not over RoCE. Is there any way to test commination over RoCE ? For eg. I was able to test it for libfabric using the below sample that comes along with libfabric to test RMA. Is there something similar for MPICH ? or use the current sample to use RoCE by some parameter? Server : fi_rma_bw -s 192.168.1.100 -e msg -d mlx5_1 -S 1024 -I 1 Client : fi_rma_bw -s 192.168.1.200 -e msg -d mlx5_3 192.168.1.100 -S 1024 -I 1 Regards, Niyaz