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compiler does not utilize all CPU?

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Old   May 18, 2020, 22:20
Default compiler does not utilize all CPU?
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Anh Dinh Le
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Dear experts,

My PC have two cpu xeon e5-2678v3, 12 cores/24 thread each cpu (total 24core/48 threads)
I submitted slurm batch job that request multicores for my code (fortran code with intel fortran compiler in linux)
I checked both serial and openMP run using the same slurm batch job file above; the same result and same calculation speed resulted.
Please tell me how to use all 2 CPU to run the code, and how to know that the code running in 1cpu or 2 cpus?

The first job file, system run with all 48 threads:
#!/bin/sh
#PBS -N Ogive
#PBS -o output
#PBS -j oe
#PBS -l ncpus=2
cd <directory>
time ./2D-TFlow2Wall-MCM-HKO

The second job file, systems run with 20 threads
#!/bin/bash

#SBATCH --job-name=testOMP
#SBATCH --nodes=1
#SBATCH --ntasks-per-node=1
#SBATCH --cpus-per-task=20
#SBATCH --exclusive
#SBATCH --time=0-20:00:00

export OMP_NUM_THREADS=${SLURM_CPUS_PER_TASK}
time ./2D-test

Last edited by AnhDL; May 19, 2020 at 00:29.
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