TP-openmp/BE_OpenMP_2014/linked_list/main.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <string.h>
#include <math.h>
#include "aux.h"
#include "omp.h"
#define MAX_SIZE 10000

unsigned long sequential_sweep(struct node *head);
unsigned long parallel_for_sweep(struct node *head);
unsigned long parallel_task_sweep(struct node *head);

int main(int argc, char **argv)
{
  int n, i, s;
  long t_start, t_end, save;
  int *x;
  unsigned long acc, result;
  struct node *head, *curr;

  init_list(&head);

  t_start = usecs();
  result = sequential_sweep(head);
  t_end = usecs();
  printf("Sequential      time    : %8.2f msec.", ((double)t_end - t_start) / 1000.0);
  printf("       -- result: %5ld\n", result);

  t_start = usecs();
  result = parallel_for_sweep(head);
  t_end = usecs();
  printf("Parallel for    time    : %8.2f msec.", ((double)t_end - t_start) / 1000.0);
  printf("       -- result: %5ld\n", result);

  t_start = usecs();
  result = parallel_task_sweep(head);
  t_end = usecs();

  printf("Parallel task   time    : %8.2f msec.", ((double)t_end - t_start) / 1000.0);
  printf("       -- result: %5ld\n", result);

  return 0;
}

unsigned long sequential_sweep(struct node *head)
{

  unsigned long acc;
  struct node *curr;

  curr = head;
  acc = 0;
  while (curr)
  {
    /* Loop until the last element in the list and accumulate the
       result of nodes processing */
    acc += process_node(curr);
    curr = curr->next;
  }

  return acc;
}

unsigned long parallel_for_sweep(struct node *head)
{
  unsigned int size = 0;
  unsigned long acc = 0;
  struct node *curr = head;

  struct node **pointers = malloc(sizeof(struct node *) * MAX_SIZE); // utiliser un std::vector en c++

  // on trouve la longuer de la liste
  while (curr)
  {
    pointers[size++] = curr;
    curr = curr->next;
  }

#pragma omp parallel
  {
#pragma omp for reduction(+ : acc)
    for (int i = 0; i < size; i++)
    {
      acc += process_node(pointers[i]);
    }

#pragma omp master
    {
      free(pointers);
    }
  }

  return acc;
}

unsigned long parallel_task_sweep(struct node *head)
{
  unsigned long acc;
  struct node *curr;

#pragma omp parallel
  {
    curr = head;
    acc = 0;

#pragma omp single
    {
      while (curr)
      {
#pragma omp task firstprivate(curr)
        {
          acc += process_node(curr);
        }
        curr = curr->next;
      }
    }
  }

  return acc;
}