ib_write_bw --rdma_cm loopback test intermittently fails with "rdma_bind_addr failed"

[panjason26-eng]

Hi,

Environment:

• OS: Ubuntu 22.04 (Linux 6.5)
• perftest version: 25.01.0-0.70

Reproduction:
I run a loopback test using two consecutive ib_write_bw commands (referencing line 219 in the attached file):

sudo ib_write_bw -d rocep77s0f1 -i 1 --rdma_cm -D 3 -s 4M --run_infinitely -F --report_gbits &
sleep 3;
sudo ib_write_bw -d rocep77s0f0 -i 1 --rdma_cm -D 3 -s 4M --run_infinitely -F --report_gbits 11.7.7.111

Observed behavior:

• The first time I run the command pair, nothing happens (it exits without output).
• The second time I run the same commands, it gets stuck with the error: "rdma_bind_addr failed".
• After interrupting and trying a third time, the commands succeed.
• If I omit the --rdma_cm option, the commands work consistently and do not show this intermittent failure.

Questions:

1. Is this intermittent behavior expected when using --rdma_cm for loopback tests, or am I using the commands incorrectly?
2. If this is a bug or an unexpected behavior, what additional logs or information would be helpful for debugging?

Attached: the referenced file (please see line 229).

Thanks for any guidance!

Jason

cx7_loopback_rdma.txt