码迷,mamicode.com
首页 > 其他好文 > 详细

使用CAS实现无锁列队-链表

时间:2018-09-29 17:44:18      阅读:172      评论:0      收藏:0      [点我收藏+]

标签:struct   next   thread   pthread   wap   cas   pac   eva   join   

#include <stdlib.h>
#include <stdio.h>
#include <pthread.h>
#include <iostream>
#include <sys/time.h>
#include <pthread.h>

using namespace std;

#define MAXLEN 200000

#define NUM_THREADS 8

#define CAS __sync_bool_compare_and_swap
#define FAA __sync_fetch_and_add
#define FAS __sync_fetch_and_sub
#define VCAS __sync_val_compare_and_swap

struct node{
    int num;
    node * next;
    node(int i, node* n) :
        num(i), next(n)
    {}
};


struct list{
    node *head;
    node *tail;
    pthread_mutex_t  lock;
    int count;
};

void init(list *plist)
{
    node *tmp = new node(0, NULL);
    plist->head = tmp;
    plist->tail = tmp;
    plist->count = 0;
    pthread_mutex_init(&(plist->lock), NULL);
}



int enque_lock(list *plist, int num)
{
    node *tmp = new node(num, NULL);
    pthread_mutex_lock(&(plist->lock));

    plist->tail->next = tmp;
    plist->tail = tmp;
    plist->count++;
    pthread_mutex_unlock(&(plist->lock));
    return 0;
}
int enque(list *plist, int num)
{
    node *p = NULL;
    node *tmp = new node(num, NULL);
    do
    {
        p = plist->tail;
    } while (CAS(&(p->next), NULL, tmp) == false);
    CAS(&(plist->tail), p, tmp);

    FAA(&(plist->count), 1);
    return 0;
}


void  deque(list *plist)
{
    node *tmp = NULL;
    do{
        tmp = plist->head;
        if (plist->head == plist->tail)
        {
            printf("err\n");
            return;
        }
    } while (CAS(&(plist->head), tmp, tmp->next) == false);
    FAS(&(plist->count), 1);
delete tmp; return; } void *SendMsg(void* p) { struct timeval tv_begin, tv_end; gettimeofday(&tv_begin, NULL); int i = 0; while (i++ < MAXLEN) { enque((list*)p, i); } gettimeofday(&tv_end, NULL); long timeinterval = (tv_end.tv_sec - tv_begin.tv_sec) * 1000000 + (tv_end.tv_usec - tv_begin.tv_usec); printf("cost %llu us\n", timeinterval); } void *SendMsg2(void* p) { struct timeval tv_begin, tv_end; gettimeofday(&tv_begin, NULL); int i = 0; while (i++ < MAXLEN) { enque_lock((list*)p, i); } gettimeofday(&tv_end, NULL); long timeinterval = (tv_end.tv_sec - tv_begin.tv_sec) * 1000000 + (tv_end.tv_usec - tv_begin.tv_usec); printf("cost %llu us\n", timeinterval); } int main(void) { int rc, i; pthread_t thread[NUM_THREADS]; list ll; init(&ll); for (i = 0; i < NUM_THREADS; i++) { printf("Creating thread %i\n", i); rc = pthread_create(&thread[i], NULL, SendMsg, (void*)&ll); if (rc) { printf("ERROR; return code is %d\n", rc); return -1; } } for (i = 0; i < NUM_THREADS; i++) { pthread_join(thread[i], NULL); } while (ll.count > 0) { deque(&ll); } for (i = 0; i < NUM_THREADS; i++) { printf("Creating thread %i\n", i); rc = pthread_create(&thread[i], NULL, SendMsg2, (void*)&ll); if (rc) { printf("ERROR; return code is %d\n", rc); return -1; } } for (i = 0; i < NUM_THREADS; i++) { pthread_join(thread[i], NULL); } return 0; }

  测试结果如下: 

Creating thread 0
Creating thread 1
Creating thread 2
Creating thread 3
Creating thread 4
Creating thread 5
Creating thread 6
Creating thread 7
cost 227839 us
cost 228055 us
cost 228034 us
cost 228179 us
cost 228274 us
cost 228328 us
cost 228413 us
cost 228433 us
Creating thread 0
Creating thread 1
Creating thread 2
Creating thread 3
Creating thread 4
Creating thread 5
Creating thread 6
Creating thread 7
cost 486283 us
cost 487499 us
cost 488358 us
cost 488677 us
cost 489118 us
cost 489658 us
cost 489657 us
cost 489735 us

加锁版 耗时 比无锁版耗时多一倍

使用CAS实现无锁列队-链表

标签:struct   next   thread   pthread   wap   cas   pac   eva   join   

原文地址:https://www.cnblogs.com/myd620/p/9724679.html

(0)
(0)
   
举报
评论 一句话评论(0
登录后才能评论!
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码!