Schecule

Static

The default schedule scheme is “static” when it is not specified in for construct.

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#include <stdio.h>
#include <omp.h>

int main ()
{
  int i, N;
  N = 6;

  #pragma omp parallel
  {
    #pragma omp for 
    for (i = 0; i < 6; i++)
      printf("Loop 1: iter %3d, thread_id %3d\n", i, omp_get_thread_num());

    #pragma omp for
    for (i = 0; i < 6; i++)
      printf("Loop 2: iter %3d, thread_id %3d\n", i, omp_get_thread_num());
  }

  return 0;
}

Dynamic

There are two ways of setting “dynamic” schedule:

  1. dynamic schedule by for construct

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    #include <stdio.h>
#include <omp.h>

int main ()
{
  int i, N;
  N = 6;

  #pragma omp parallel
  {
    #pragma omp for schedule(dynamic,1)
    for (i = 0; i < 6; i++)
      printf("Loop 1: iter %3d, thread_id %3d\n", i, omp_get_thread_num());

    #pragma omp for schedule(dynamic,1)
    for (i = 0; i < 6; i++)
      printf("Loop 2: iter %3d, thread_id %3d\n", i, omp_get_thread_num());
  }

  return 0;
}

  2. dynamic schedule by environment variables

    1
    export OMP_SCHEDULE=“dynamic,1”

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    #include <stdio.h>
#include <omp.h>

int main ()
{
  int i, N;
  N = 6;

  #pragma omp parallel
  {
    #pragma omp for 
    for (i = 0; i < 6; i++)
      printf("Loop 1: iter %3d, thread_id %3d\n", i, omp_get_thread_num());

    #pragma omp for
    for (i = 0; i < 6; i++)
      printf("Loop 2: iter %3d, thread_id %3d\n", i, omp_get_thread_num());
  }

  return 0;
}