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--- doku:multimpi [2021/04/01 07:03] – markus
+++ doku:multimpi [2022/11/04 10:45] – [With srun:] goldenberg
@@ Line 5: / Line 5: @@
 ==== VSC-4 =====
-Sample Job when for running multiple mpi jobs on a VSC-4 node. Note:
+Sample Job when for running multiple mpi jobs on a VSC-4 node.
+Note: The "mem_per_task" should be set such that
+<code>
+mem_per_task * mytasks < mem_per_node - 2Gb
+</code>
+The approx 2Gb reduction in available memory is due to operating system stored in memory. For a standard node with 96 Gb of Memory this would be eg.:
+<code>
+Gb * 4 = 92 Gb < 94 Gb
+</code>
 <code>
@@ Line 27: / Line 39: @@
 ==== VSC-3 =====
-=== With srun: ===
-<code>
-#!/bin/bash
-#SBATCH -J test
-#SBATCH -N 1
-#SBATCH --ntasks-per-core=1
-#SBATCH --ntasks-per-node=2
-export SLURM_STEP_GRES=none
-module load intel/18 intel-mpi/2018
-for i in 0 8
-do
-  j=$(($i+1))
-  srun -n 2 --cpu_bind=map_cpu:$i,$j ./hello_world_intelmpi2018 &
-done
-wait
-exit 0
-</code>
-=== With mpirun (Intel MPI): ===
-<code>
-#!/bin/bash
-#SBATCH -J test
-#SBATCH -N 1
-#SBATCH --ntasks-per-core=1
-#SBATCH --ntasks-per-node=2
-export SLURM_STEP_GRES=none
-module load intel/18 intel-mpi/2018
-for i in 0 8
-do
-  j=$(($i+1))
-  mpirun -env I_MPI_PIN_PROCESSOR_LIST $i,$j -np 2 ./hello_world_intelmpi2018 &
-done
-wait
-exit 0
-</code>
-You can download the C code example here: {{ :doku:hello_world.c |hello_world.c}}
-Compile it e.g. with:
-<code>
-# module load intel/18 intel-mpi/2018
-# mpiicc -lhwloc hello_world.c -o hello_world_intelmpi2018
-</code>