Shared Memory

OpenMP - most popular shared memory API

Already included in the compiler module

Serial

#include <iostream>

int main()

{
  std::count << “\nHello World”
  return 0;

}

icc fooOMP.c -o fooOMP.x
gcc fooOMP.c -o fooOMP.x

Parallel OpenMP

#include <iostream>
#include “omp.h”
int main() {
#pragma omp parallel
{
  std::count << “\nHello World”
}
  return 0;
}

icc -openmp fooOMP.c -o fooOMP.x
gcc -fopenmp fooOMP.c -o fooOMP.x

Sets up number of threads

[ ccp 00 51@t3 - log in2    scripts]$ cat test.job #!/bin/bash
#SBATCH -N 1 ### Num of compute nodes
#SBATCH -n 28 ##* Num of CPUs/cores
#SBATCH -p compute #*#paraition (always compute)
#SBATCH --qos general **#QOS (debug,general, large)
#SBATCH -J hello### Jobname
#SBATCH --mail-user=charles.peterson@unt.edu #SBATCH --mail-type=begin
#SBATCH --mail-type=end

module load intel/PS2017-17.0.4-legacy

##SETTING UP OMP VARIABLES
export OMP_NUM_THREADS=l6

##Running code
/home/ccp00Sl/apps/fooOMP.x

[ccp0051@t3-login2 scripts]$ sbatch test.job