Identical behavior for 4.1.8 On Monday, April 20, 2026 at 1:49:22 PM UTC-4 Noam Bernstein wrote:
> I'm testing 4.1.8 now > > On Monday, April 20, 2026 at 1:44:35 PM UTC-4 Noam Bernstein wrote: > >> Specifically, this is happening on 32 core nodes, and it looks like the >> second syntax refuses to see the second node. >> >> The first syntax shows one task bound to each physical core on one node, >> then one to each physical core on the second node. >> >> The second works up to 8 tasks, and each are bound to 4 cores on the >> first node, but as soon as I exceed that it complains, perhaps because it's >> trying to bind the tasks that are supposed to be on the 2nd node to the 1st >> node's cores. >> >> This is openmpi 4.1.4, on Rocky 8, BTW >> >> On Monday, April 20, 2026 at 12:56:56 PM UTC-4 Noam Bernstein wrote: >> >>> Can anyone tell me why this works (i.e. I have 64 cores available) >>> mpiexec -n 64 --report-bindings --bind-to core --rank-by core >>> --map-by core --mca pml ucx --mca osc ucx --mca btl ^vader,tcp,openib exec >>> with the expected bindings while this (should also take 16 * 4 = 64 >>> cores) >>> mpiexec -n 16 --report-bindings --bind-to core --rank-by core >>> --map-by slot:PE=4 --mca pml ucx --mca osc ucx --mca btl ^vader,tcp,openib >>> exec >>> >>> Fails with: >>> >>> A request was made to bind to that would result in binding more >>> processes than cpus on a resource: >>> >>> Bind to: CORE >>> Node: compute-7-4 >>> #processes: 2 >>> #cpus: 1 >>> >>> You can override this protection by adding the "overload-allowed" >>> option to your binding directive. >>> >> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
