一、协程
协程，又叫微线程，纤程。英文名Coroutine。协程本质上就是一个线程
优点1：协程极高的执行效率。因为子程序切换不是线程切换，而是由程序自身控制，因此，没有线程切换的开销，和多线程比，线程数量越多，协程的性能优势就越来越明显。(简单来说没有切换的消耗)
优点2：不需要多线程的锁机制，因为只有一个线程，也不存在同时写变量冲突，在协程中控制共享资源不加锁，只需要判断状态就好，所以执行效率比多线程高很多。(没有锁的概念)
因为协程是一个线程执行，那怎么利用多核CPU呢？最简单的方法是多进程+协程，既充分利用多核，又充分发挥协程的高效率，可获得极高的性能。
二、yield的简单实现
#_*_ coding:utf-8 _*_
# Author:Simon
# Datetime:2019/9/2 21:07
# Software:PyCharm
import
time
import
queue
def
consumer(name):
print("--->ready to eat baozi..."
)
while
True:
new_baozi = yield
print("[%s] is eating baozi %s" %
(name,new_baozi)) #time.sleep(1) def
producer(): r = con.__next__
() r = con2.__next__
() n =
0 while 1
: time.sleep(1
) print("\033[32;1m[producer]\033[0m is making baozi %s and %s" %(n,n+1
) ) con.send(n) con2.send(n+1
) n +=2 if __name__ == '__main__'
: con = consumer("c1"
) con2 = consumer("c2"
) p = producer()
三、Greenlet模块
greenlet是一个用C实现的协程模块，相比与python自带的yield，它可以使你在任意函数之间随意切换，而不需把这个函数先声明为generator
#_*_ coding:utf-8 _*_
# Author:Simon
# Datetime:2019/9/2 21:29
# Software:PyCharm
from greenlet import
greenlet
def
test1():
print(12
)
gr2.switch()
print(34
)
gr2.switch()
def
test2():
print(56
) gr1.switch() print(78
) gr1 =
greenlet(test1) gr2 =
greenlet(test2) gr1.switch()
四、Gevent模块
本质就是封装了greenlet模块，它能检测I/O并且遇到I/O自动切换到另外一个任务执行；可以帮我们提升效率
#_*_ coding:utf-8 _*_
# Author:Simon
# Datetime:2019/9/2 21:39
# Software:PyCharm
import
gevent
import
requests,time
start=
time.time()
def
f(url):
print('GET: %s' %
url)
resp =
requests.get(url) data =
resp.text print('%d bytes received from %s.' %
(len(data), url)) gevent.joinall([ gevent.spawn(f, 'https://www.jd.org/'
), gevent.spawn(f, 'https://www.xiaohua.com/'
), gevent.spawn(f, 'https://www.baidu.com/'
), gevent.spawn(f, 'https://www.taobao.com/'
), ]) # f('https://www.jd.org/') # f('https://www.xiaohua.com/') # f('https://baidu.com/') # f('https://www.taobao.com/') # # print("cost time:",time.time()-start)
gevent异步提交任务
from gevent import
monkey;monkey.patch_all()
import
gevent
import
time
def
eat(name):
print('%s eat 1' %
name)
time.sleep(3
) print('%s eat 2' %
name) def
play(name): print('%s play 1' %
name) time.sleep(4
) print('%s play 2' %
name) g1=gevent.spawn(eat,'simon'
) g2=gevent.spawn(play,'zhuzhu'
) # time.sleep(5) # g1.join() # g2.join()
gevent.joinall([g1,g2]) #相当于上边两行代码
打印： simon eat 1
zhuzhu play 1
simon eat 2
zhuzhu play 2
基于gevent模块实现并发的套接字通信
单线程、多任务的I/O操作。
#基于gevent实现
from gevent import
monkey,spawn;monkey.patch_all()
from socket import *
def
communicate(conn):
while
True:
try
:
data=conn.recv(1024
)
if not data:break
conn.send(data.upper()) except
ConnectionResetError: break
conn.close() def
server(ip,port): server =
socket(AF_INET, SOCK_STREAM) server.bind((ip,port)) server.listen(5
) while
True: conn, addr =
server.accept() spawn(communicate,conn) #造一个协程对象，提交完这个对象它不会执行
server.close() if __name__ == '__main__'
: g=spawn(server,'127.0.0.1',8090
) g.join()
##客户端
from socket import *
from threading import
Thread,currentThread
def
client():
client=
socket(AF_INET,SOCK_STREAM)
client.connect(('127.0.0.1',8090
))
while
True:
client.send(('%s hello' %currentThread().getName()).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()
