<div dir="ltr">Source: openmpi<br>Version: 5.0.6-3<br><br>Dear Maintainer,<br><br>UCX is disabled in /etc/openmpi/openmpi-mca-params.conf by no-warning-unused.patch:<br><br><a href="https://sources.debian.org/src/openmpi/5.0.6-3/debian/patches/no-warning-unused.patch/">https://sources.debian.org/src/openmpi/5.0.6-3/debian/patches/no-warning-unused.patch/</a><br><br>with the motivation to silence warnings when RDMA devices are not available:<br><br><a href="https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=980033">https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=980033</a><br><a href="https://github.com/open-mpi/ompi/issues/8367">https://github.com/open-mpi/ompi/issues/8367</a><br><br>Could UCX be re-enabled? I believe recent versions should no longer produce these messages.<br><br>Re-enabling would also restore OpenMPI's default behavior of selecting UCX for Infiniband-enabled systems. At the moment, OpenMPI is falling back to ob1 for Infiniband communication, which has been significantly less performant in our testing.<br><br>To enable UCX, we're adjusting /etc/openmpi/openmpi-mca-params.conf from:<br><br>mtl = ^ofi<br>btl = ^uct,openib,ofi<br>pml = ^ucx<br>osc = ^ucx,pt2pt<br><br>to:<br><br>mtl = ^ofi<br>btl = ^openib,ofi<br>osc = ^pt2pt<br><br>I couldn't comment on openfabric/openib.<br><br><br>-- System Information:<br>Debian Release: trixie/sid<br>  APT prefers testing<br>  APT policy: (500, 'testing')<br>Architecture: amd64 (x86_64)<br><br>Kernel: Linux 6.11.7-amd64 (SMP w/4 CPU threads; PREEMPT)<br>Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en<br>Shell: /bin/sh linked to /usr/bin/dash<br>Init: systemd (via /run/systemd/system)<br>LSM: AppArmor: enabled<br></div>