[slurm-users] requesting entire vs. partial nodes

[Noam Bernstein]

Hi - I have a slurm usage question that I haven't been able to figure out from the docs.  We basically have two types of jobs - ones that require entire nodes, and ones that do not.  An additional (minor) complication is that the nodes have hyperthreading enabled, but we want (usually) to use only one task per physical core (in both kinds of jobs). What's the best way to request resources from sbatch to ensure this happens?  Would the following produce this effect?

entire node: --nodes=number_of_nodes --tasks_per_node=number_of_cores_per_node
partial node: --ntasks=total_number_of_tasks --tasks-per-core=1

If not, is there another way to do this?  

And however we achieve this, how does slurm decide what order to assign nodes to jobs in the presence of jobs that don't take entire nodes.  If we have a 2 16 core nodes and two 8 task jobs, are they going to be packed into a single node, or each on its own node (leaving no free node for another 16 task job that requires an entire node)?

											thanks,
											Noam

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