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电梯直达

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发表于 2009-04-15 17:36 |只看该作者 |倒序浏览

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第一次用openmp 做个并行多线程编程。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/time.h>
#include <unistd.h>
#include <omp.h>

typedef struct barrel
{
    char str[8];
    struct barrel * next;
}barrel_t;

barrel_t* B[96];

barrel_t* init_barrel()
{
    barrel_t *head;
    head=(barrel_t *)malloc(sizeof(barrel_t));
    strcpy(head->str,"start");
    head->next=NULL;
    return head;
}

barrel_t* insert_barrel(barrel_t* head,char* insertstr)
{
    barrel_t *p,*q;
    q = head;
    p = (barrel_t *)malloc(sizeof(barrel_t));
    strcpy(p->str,insertstr);    
    
    if (head==NULL)
    {
        head = p;p->next=NULL;
        return head;
    }
    while (q->next!=NULL)
    {    
        q=q->next;
    }
    q->next = p;    
    p->next = NULL;    
    return head;
}

barrel_t * pop_one(barrel_t *head)
{
    barrel_t *p ,*q;
    p=head;
    if (head==NULL||head->next==NULL)
    {        
        return NULL;
    }
    q = p->next;
    p->next = q->next;
    return q;
}

void free_barrel(barrel_t *head)
{
    barrel_t * p,* q;
    p=head;
    if (p==NULL)
    {
    //    printf("List is null!\n");    

    }

    while (p!=NULL)
    {        
        q = p;
        p = p->next;
        free(q);
    }
}

int bucket(char **a,int j)
{
    int i=0;
    for (i=0;i<8;i++)
    {
    //    printf("a[%d][%d] = %c one!\n",i,j,a[j]);

        insert_barrel(B[a[i][j]-32],a[i]);
    }
//    printf("\n\n");

    return 0;
}

int main()
{
    int nthreads = 4;
    omp_set_num_threads(nthreads);

    long start_time,end_time;
    struct timeval start_time_tv,end_time_tv;
    struct timezone tz;
    
    char *a[8] =
    {
            "H@skell",
            "surVEYs",
            "sysTEMS",
            "HASKELL",
            "Surveys",
            "1234567",
            "SURveys",
            "systEMS"
    };
    int i=0;
    int j;
    int k=0;
    gettimeofday (&start_time_tv, &tz);
//    start_time=start_time_tv.tv_sec*1000000+start_time_tv.tv_usec;

//    printf("start_time = %ld\n",start_time_tv.tv_sec);

    
    #pragma omp parallel
    {
        int id = omp_get_thread_num();
    #pragma omp for
    for (i=0;i<96;i++)
    {
        B[i] = init_barrel();
        printf("Hello World from thread = %d", id);
        printf(" with %d threads\n",omp_get_num_threads());
    }
    }

// #pragma omp parallel for

    for(j=6;j>=0;j--)
    {
        i=0;
        bucket(a,j);    
        for (k=0;k<96;k++)
        {        
            while (B[k]->next!=NULL)
            {
                //printf("k = %d \n",k);

                barrel_t * p;
                p=pop_one(B[k]);
                a[i++] = p->str;
            }
        }
    }
    //#pragma omp parallel for

    for (i=0;i<96;i++)
    {
        free_barrel(B[k]);
    }

    gettimeofday (&end_time_tv , &tz);
//    end_time=end_time_tv.tv_sec*1000000+end_time_tv.tv_usec;

    printf("It takes %ld ms\n",(end_time_tv.tv_sec - start_time_tv.tv_sec)*1000000 + (end_time_tv.tv_usec - start_time_tv.tv_usec) );

    for (i=0;i<8;i++)
    {
        printf("%s\n",a[i]);
    }
    

}