day 32

ゝ一纸荒年。 2021-09-29 06:40 372阅读 0赞

一.进程池与线程池

# def task(name):
    #     print("%s%s is running " %(name,os.getpid()))
    #     time.sleep(random.randint(1,3))
    #
    # if __name__ == '__main__':
    #     p=ProcessPoolExecutor(4) #创建进程池的个数
    #     #提交任务
    #     #同步提交:提交完一个任务后,就在原地等待,等待任务完完整整地运行完毕后拿到结果,在执行下一行代码,会导致任务是串行执行的
    #     #异步提交:提交完一个任务后,不在原地等待,而是直接执行下一行代码,会导致执行是并发的
    #     li=[]
    #     #同步提交
    #     for i  in range(10):
    #         # res = p.submit(task,'线程id:').result()
    #         # print(res)
    #
    #     #异步提交
    #
    #         future=p.submit(task,"线程id:")
    #         li.append(future)
    #
    #     p.shutdown(True)      #关闭进程池的入口,并且在原地等待进程池内所有任务运行完毕
    #
    #     for future in li:
    #         print(future.result())
    #     print("主")

二.

def get(url):
        print("%s GET %s" % (current_thread().name, url))
        time.sleep(3)
        response = requests.get(url)
        if response.status_code == 200:
            res = response.text
        else:
            res = '下载失败'
        return  res
    
    
    def pase(future):
        time.sleep(1)
        res= future.result()
        print("%s 解析的结果为:%s" % (current_thread().name, len(res)))
    
    
    if __name__ == '__main__':
        urls = ['http://www.baidu.com',
                'http://www.sina.com',
                'http://www.tmall.com',
                'http://www.jd.com',
                'http://www.python.org',
                'http://www.openstack.com'
                ]
        p = ProcessPoolExecutor(6)
        li = []
        strat = time.time()
        for url in urls:  # 可以理解为开启进程数的个数
            future = p.submit(get, url)
            future.add_done_callback(pase)  #pase会将任务运行完毕后会自动触发,然后接受一个参数futur对象
        p.shutdown(True)                    #关闭进程池的入口,并且在原地等待进程池内所有任务运行完毕
        print("主", time.time() - strat)

三.利用线程池和进程池实现套接字的并发

from socket import *
    from concurrent.futures import ProcessPoolExecutor, ThreadPoolExecutor
    from multiprocessing import Process
    
    
    def comunicate(conn):
        while True:  # 通信循环
            try:
                data = conn.recv(1024)
                if len(data) == 0: break
                conn.send(data.upper())
            except ConnectionResetError:
                break
        conn.close()
    
    
    def server():
        server = socket(AF_INET, SOCK_STREAM)
        server.bind(("127.0.0.1", 8081))
        server.listen(5)
    
        while True:  # 链接循环
            conn, client_addr = server.accept()
            print(client_addr)
            # 通信
            t = Process(target=comunicate, args=(conn,))
            t.start()
    
    
    if __name__ == '__main__':
        p = ProcessPoolExecutor(6)
        for i in range(4):
            future = p.submit(server, )
            # future.add_done_callback(comunicate)  # 回调函数   communciate会将任务运行完毕后会自动触发,然后接受一个参数futur对象

四.协程

'''
    1. 目标:
        在线程下实现并发
            并发(多个任务看起来是同时执行就是并发):切换+保存状态
    
    2. 协程:
        协程是单线程实现并发
        注意:协程是程序员意淫出来的东西,操作系统里只有进程和线程的概念(操作系统调度的是线程)
    
        在单线程下实现多个任务间遇到IO就切换就可以降低单线程的IO时间,从而最大限度地提升单线程的效率
    
    
    '''
    
    #串行执行
    import time
    
    def func1():
        for i in range(10000000):
            i+1
    
    def func2():
        for i in range(10000000):
            i+1
    
    start = time.time()
    func1()
    func2()
    stop = time.time()
    print(stop - start)
    
    
    #基于yield并发执行
    import time
    def func1():
        while True:
            print('func1')
            10000000+1
            yield
    
    def func2():
        g=func1()
        for i in range(10000000):
            print('func2')
            time.sleep(100)
            i+1
            next(g)
    
    start=time.time()
    func2()
    stop=time.time()
    print(stop-start)

五.

from gevent import monkey;monkey.patch_all()
    from gevent import spawn,joinall #pip3 install gevent
    import time
    
    def play(name):
        print('%s play 1' %name)
        time.sleep(5)
        print('%s play 2' %name)
    
    def eat(name):
        print('%s eat 1' %name)
        time.sleep(3)
        print('%s eat 2' %name)
    
    
    start=time.time()
    g1=spawn(play,'刘清正')
    g2=spawn(eat,'刘清正')
    
    # g1.join()
    # g2.join()
    joinall([g1,g2])
    print('主',time.time()-start)

转载于:https://www.cnblogs.com/jxl123/p/9619761.html