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<p class="MsoNormal">With sbatch, what is the proper way to launch 5 tasks each on a single node, but reserve two slots on each node so that the original tasks can each create one new process using MPI_Comm_spawn?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’ve tried various combinations of the sbatch arguments –nodes, --ntasks-per-node and –cpu-per-node, but all attempts result in this OpenMpi error message:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><b>“All nodes which are allocated for this job are already filled.”<o:p></o:p></b></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I expected the proper arguments to be –nodes=5 --ntasks=5 –cpus-per-task=2.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The 5 original processes are created correctly, but it seems like MPI_Comm_spawn is causing the error message when it tries to allocate a CPU.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m using slurm 20.11.8 and OpenMpi 4.1.2.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Kurt<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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