example of explicit binding to cpu's

CADES/ARB_CODE/many_small_mpiruns.sh

+#!/bin/bash
+##PBS -S /bin/bash
+#PBS -m be
+#PBS -N h2so4
+#PBS -q cnms14q
+#PBS -l nodes=2:ppn=32
+#PBS -l walltime=24:00:00
+
+source /opt/modules/3.1.6/init/bash
+#cd $GLOBAL_SCRATCH
+cd $PBS_O_WORKDIR
+export MODULEPATH=$MODULEPATH:/projects/cnms/modules
+
+module load whatever
+
+export OMP_NUM_THREADS=1
+
+cd $PBS_O_WORKDIR
+
+#this can be useful to see from outside shells
+cat $PBS_NODEFILE >pbs_nodefile
+cores_per_node=32
+wcr=($(wc pbs_nodefile))
+count=${wcr[0]}
+awk -v count=$count -v cpn=$cores_per_node 'BEGIN { a= 0; r=0; cores=count/2; prev_node="" }; { if (a < cpn) { print "rank " r "=" $1 " slot=" a; r = r + 1; a = a + 2; prev_node=$1 } else { if (r < cores && prev_node != $1 ) {a = 0; print "rank " r "=" $1 " slot=" a ; r = r + 1; a = a + 2} }}' pbs_nodefile > rankfile
+
+#VASP runs including significant communication especially for SCALAPACK run
+#slower than they should.  Refrain from using more than ~1 cpu per atom
+#past 64 or 128 cores LSCALAPACK=.FALSE.
+
+mpirun -n $((count / 2)) -v --report-bindings -rf rankfile ${VASP_MPI_FLAGS} $VASP 2>&1 >vasp_out