Hi Alan, unfortunately, process placement in Slurm is kind of black magic for sub-node jobs, i.e. jobs that allocate only a small number of CPUs of a node.
I have recently raised a similar question here: https://support.schedmd.com/show_bug.cgi?id=19236 And the buttom line was, that to "really have control over task placement you really have to allocate the node in --exclusive manner". Best regards Jürgen * Alan Stange via slurm-users <slurm-users@lists.schedmd.com> [240607 14:52]: > All, > > I have a very simple slurm cluster. It's just a single system with 2 > sockets and 16 cores in each socket. I would like to be able to submit > a simple task into this cluster, and to have the cpus assigned to that > task allocated round robin across the two sockets. Everything I try is > putting all the cpus for this single task on the same socket. > > I have not specified any CpuBind options in the slurm.conf file. For > example, if I try > > $ srun -c 4 --pty bash > > I get a shell prompt on the system, and can run > > $ taskset -cp $$ > pid 12345 current affinity list: 0,2,4,6 > > and I get this same set of cpus no matter what options I try (the > cluster is idle with no tasks consuming slots). > > I've tried various srun command line options like: > --hint=compute_bound > --hint=memory_bound > various --cpubind options > -B 2:2 -m block:cyclic and block:fcyclic > > Note that if I try to allocation 17 cpus, then I do get the 17th cpu > allocated on the 2nd socket. > > > What magic incantation is needed to get an allocation where the cpus are > chosen round robin across the sockets? > > Thank you! > > Alan > > > -- > slurm-users mailing list -- slurm-users@lists.schedmd.com > To unsubscribe send an email to slurm-users-le...@lists.schedmd.com -- Jürgen Salk Scientific Software & Compute Services (SSCS) Kommunikations- und Informationszentrum (kiz) Universität Ulm Telefon: +49 (0)731 50-22478 Telefax: +49 (0)731 50-22471
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