标签：io阻塞 -- 补丁 线程 问题 patch art 打补丁 def
协程：是单线程下的并发，又称微线程。英文名Coroutine。
协程是一种用户态的轻量级线程，即协程是由用户程序自己控制调度的。
需要强调的是：
1. python的线程属于内核级别的，即由操作系统控制调度
（如单线程遇到io或执行时间过长就会被迫交出cpu执行权限，切换其他线程运行）
2. 单线程内开启协程，一旦遇到io，就会从应用程序级别（而非操作系统）控制切换，
以此来提升效率（！！！非io操作的切换与效率无关）
协程实现
def consumer(): while True: res = yield print("消费了%s"%res) def producer(c): for i in range(3): print("生产了%s"%i) c.send(i) c =consumer() # 创建消费者 c.send(None) # 启动消费者 producer(c) # 生产者发送数据 c.close() # 关闭消费者
from greenlet import greenlet def eat(name): print("%s is eating" % name) g2.switch(‘yk‘) print("%s is eating" % name) g2.switch() def play(name): print("%s is playing phone" % name) g1.switch() print("%s is playing phone" % name) if __name__ == ‘__main__‘: g1 = greenlet(eat) g2 = greenlet(play) g1.switch(‘yk‘) # 先让g1 开启 ‘‘‘ yk is eating yk is playing phone yk is eating yk is playing phone ‘‘‘
greenlet只是提供了一种比generator更加便捷的切换方式，当切到一个任务执行时如果遇到io，
那就原地阻塞，仍然是没有解决遇到IO自动切换来提升效率的问题。
gevent 遇到 I/O会自动切换。 ``` import gevent # 遇到 I/O自动切换 def eat(name): print(‘%s eat 1‘ % name) gevent.sleep(2) # 模拟的是gevent可以识别的io阻塞 print(‘%s eat 2‘ % name) def play(name): print(‘%s play 1‘ % name) gevent.sleep(1) print(‘%s play 2‘ % name) g1 = gevent.spawn(eat, ‘dx‘) # 创建一个协程对象g1，spawn括号内第一个参数是函数名，如eat，后面可以有多个参数 g2 = gevent.spawn(play, name=‘yk‘) g1.join() g2.join() # 或者gevent.joinall([g1,g2]) print(‘主‘) ‘‘‘ dx eat 1 yk play 1 yk play 2 dx eat 2 主 ‘‘‘
打补丁
from gevent import monkey;monkey.patch_all() # 打补丁 # 要想识别time模块，得在前面导入monkey;monkey.patch_all() import gevent import time def eat(): print(‘eat food 1‘) time.sleep(2) print(‘eat food 2‘) def play(): print(‘play 1‘) time.sleep(1) print(‘play 2‘) g1=gevent.spawn(eat) g2=gevent.spawn(play) gevent.joinall([g1,g2]) print(‘主‘) ```
gevent 实现并发通信
------------------------服务端------------------- from gevent import monkey monkey.patch_all() import gevent import socket def communute(conn): while True: try: data = conn.recv(1024) if not data: break print("客户端数据->", data) conn.send(data.upper()) except ConnectionResetError: break conn.close() def serve(): server = socket.socket(socket.AF_INET, socket.SOCK_STREAM) server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) server.bind(("localhost", 8080)) server.listen(5) print("等待连接") while True: conn, client_addr = server.accept() print("来自%s连接成功" % client_addr[0]) gevent.spawn(communute, conn) server.close() if __name__ == ‘__main__‘: serve() ---------------------客户端------------------ import socket from threading import Thread, current_thread def client(): client = socket.socket(socket.AF_INET, socket.SOCK_STREAM) client.connect((‘127.0.0.1‘, 8080)) while True: msg = ‘%s hello‘ % current_thread() client.send(msg.encode(‘utf-8‘)) data = client.recv(1024) print(data.decode(‘utf-8‘)) client.close() if __name__ == ‘__main__‘: for i in range(500): t = Thread(target=client) t.start()
标签：io阻塞 -- 补丁 线程 问题 patch art 打补丁 def
原文地址：https://www.cnblogs.com/ykgo/p/9379371.html
