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  • 多线程、多进程、协程

    多线程
     1 #使用线程锁
 2 #要在产生资源抢占的地方加锁
 3 #一定不要在IO的地方加，否则就变成同步执行了
 4 #coding:utf8
 5 import threading
 6 import time
 7 
 8 lock = threading.Lock()
 9 
10 def print_time(thread_name,delay):
11     count = 0
12     while count<5:
13         time.sleep(delay)
14         lock.acquire()
15         count+=1
16         print(thread_name,time.ctime(time.time()))
17         lock.release()
18 
19 t_name_list = ['t1','t2','t3']
20 t_list = []
21 for t_name in t_name_list:
22     work = threading.Thread(target=print_time,args=(t_name,1,))
23     work.start()
24     t_list.append(work)
25 
26 for t in t_list:
27     t.join()
28 
29 print 'end---------'
30 
31 结果：有序，用锁保证当前线程操作的原子性，共用5s
32 ('t2', 'Mon May 21 11:52:36 2018')
33 ('t1', 'Mon May 21 11:52:36 2018')
34 ('t3', 'Mon May 21 11:52:36 2018')
35 ('t1', 'Mon May 21 11:52:37 2018')
36 ('t2', 'Mon May 21 11:52:37 2018')
37 ('t3', 'Mon May 21 11:52:37 2018')
38 ('t1', 'Mon May 21 11:52:38 2018')
39 ('t2', 'Mon May 21 11:52:38 2018')
40 ('t3', 'Mon May 21 11:52:38 2018')
41 ('t3', 'Mon May 21 11:52:39 2018')
42 ('t1', 'Mon May 21 11:52:39 2018')
43 ('t2', 'Mon May 21 11:52:39 2018')
44 ('t2', 'Mon May 21 11:52:40 2018')
45 ('t1', 'Mon May 21 11:52:40 2018')
46 ('t3', 'Mon May 21 11:52:40 2018')
47 end---------
    加了锁的多线程
     1 线程池的方式
 2 
 3 #coding:utf8
 4 import threading
 5 import time
 6 import threadpool
 7 
 8 lock = threading.Lock()
 9 
10 def print_time(thread_name):
11     count = 0
12     while count<5:
13         time.sleep(1)
14         lock.acquire()
15         count+=1
16         print(thread_name,time.ctime(time.time()))
17         lock.release()
18 
19 t_name_list = ['t1','t2','t3']
20 pool = threadpool.ThreadPool(2)
21 requests = threadpool.makeRequests(print_time, t_name_list)
22 for req in requests:
23     pool.putRequest(req)
24 pool.wait()
25 print 'end---------'
26 
27 
28 结果：有序，10s
29 ('t1', 'Mon May 21 15:02:22 2018')
30 ('t2', 'Mon May 21 15:02:22 2018')
31 ('t1', 'Mon May 21 15:02:23 2018')
32 ('t2', 'Mon May 21 15:02:23 2018')
33 ('t1', 'Mon May 21 15:02:24 2018')
34 ('t2', 'Mon May 21 15:02:24 2018')
35 ('t1', 'Mon May 21 15:02:25 2018')
36 ('t2', 'Mon May 21 15:02:25 2018')
37 ('t1', 'Mon May 21 15:02:26 2018')
38 ('t2', 'Mon May 21 15:02:26 2018')
39 ('t3', 'Mon May 21 15:02:27 2018')
40 ('t3', 'Mon May 21 15:02:28 2018')
41 ('t3', 'Mon May 21 15:02:29 2018')
42 ('t3', 'Mon May 21 15:02:30 2018')
43 ('t3', 'Mon May 21 15:02:32 2018')
44 end---------
    threadpool库实现
     1 自己实现的线程池，有很多问题，但大致原理是对的
 2 #coding:utf8
 3 import threading
 4 import Queue
 5 import time
 6 
 7 lock = threading.Lock()
 8 
 9 class ThreadPool():
10     def __init__(self,max_num=20):
11         self._max_num = max_num
12         self.queue = Queue.Queue(max_num)
13         for i in range(max_num):
14             self.queue.put(threading.Thread)
15 
16     def get_thread(self):
17         return  self.queue.get()
18 
19     def add_thread(self):
20         self.queue.put(threading.Thread)
21 
22 def func(pool,a1):
23     time.sleep(1)
24     lock.acquire()
25     print(a1)
26     lock.release()
27     pool.add_thread()
28 
29 p = ThreadPool()
30 for i in range(100):
31     thread = p.get_thread()
32     t = thread(target=func, args=(p, i,))
33     t.start()
    自己实现线程池
     1 #使用系统自带的库
 2 from concurrent.futures import ThreadPoolExecutor,wait
 3 import time
 4 
 5 #创建线程池
 6 pool = ThreadPoolExecutor(max_workers=2)
 7 
 8 #线程池中实现了线程安全，不用加锁了
 9 def print_time(thread_name):
10     count = 0
11     while count<5:
12         time.sleep(1)
13         count+=1
14         print(thread_name,time.ctime(time.time()))
15 
16 
17 t_name_list = ['t1','t2','t3']
18 
19 fs = []
20 for t_name in t_name_list:
21     f = pool.submit(print_time,t_name)
22     fs.append(f)
23 #相遇与join，阻塞主线程
24 wait(fs)
25 print('end---------')
26 
27 结果：有序，10s
28 t2 Mon May 21 21:26:38 2018
29 t1 Mon May 21 21:26:38 2018
30 t1 Mon May 21 21:26:39 2018
31 t2 Mon May 21 21:26:39 2018
32 t2 Mon May 21 21:26:40 2018
33 t1 Mon May 21 21:26:40 2018
34 t2 Mon May 21 21:26:41 2018
35 t1 Mon May 21 21:26:41 2018
36 t2 Mon May 21 21:26:42 2018
37 t1 Mon May 21 21:26:42 2018
38 t3 Mon May 21 21:26:43 2018
39 t3 Mon May 21 21:26:44 2018
40 t3 Mon May 21 21:26:45 2018
41 t3 Mon May 21 21:26:46 2018
42 t3 Mon May 21 21:26:47 2018
43 end---------
    ThreadPoolExecutor线程池
     1 #使用gevent，即协程，使用方法和线程类似
 2 from gevent import monkey
 3 #monkey补丁，改变底层
 4 monkey.patch_all()
 5 import gevent
 6 import time
 7 
 8 #协程的方式
 9 
10 def print_time(thread_name):
11     count = 0
12     while count<5:
13         gevent.sleep(1)
14         count+=1
15         print(thread_name,time.ctime(time.time()))
16 
17 
18 t_name_list = ['t1','t2','t3']
19 gs = []
20 for t_name in t_name_list:
21     g = gevent.spawn(print_time,t_name)
22     gs.append(g)
23 for g1 in gs:
24     g1.join()
25 print('end-----')
26 
27 结果：有序，5s
28 t1 Mon May 21 21:50:23 2018
29 t2 Mon May 21 21:50:23 2018
30 t3 Mon May 21 21:50:23 2018
31 t1 Mon May 21 21:50:24 2018
32 t2 Mon May 21 21:50:24 2018
33 t3 Mon May 21 21:50:24 2018
34 t1 Mon May 21 21:50:25 2018
35 t2 Mon May 21 21:50:25 2018
36 t3 Mon May 21 21:50:25 2018
37 t1 Mon May 21 21:50:26 2018
38 t2 Mon May 21 21:50:26 2018
39 t3 Mon May 21 21:50:26 2018
40 t1 Mon May 21 21:50:27 2018
41 t2 Mon May 21 21:50:27 2018
42 t3 Mon May 21 21:50:27 2018
43 end-----
    协程(gevent)
     1 #协程池的方式，感觉意义不大
 2 from gevent import monkey
 3 monkey.patch_all()
 4 import gevent
 5 import time
 6 from gevent.pool import Pool
 7 
 8 #协程池的方式
 9 pool = Pool(2)
10 
11 def print_time(thread_name):
12     count = 0
13     while count<5:
14         gevent.sleep(1)
15         count+=1
16         print(thread_name,time.ctime(time.time()))
17 
18 
19 t_name_list = ['t1','t2','t3']
20 gs = []
21 for t_name in t_name_list:
22     pool.spawn(print_time,t_name)
23 pool.join()
24 print('end-----')
25 
26 结果：有序，10s
27 t1 Mon May 21 21:48:30 2018
28 t2 Mon May 21 21:48:30 2018
29 t1 Mon May 21 21:48:31 2018
30 t2 Mon May 21 21:48:31 2018
31 t1 Mon May 21 21:48:32 2018
32 t2 Mon May 21 21:48:32 2018
33 t1 Mon May 21 21:48:33 2018
34 t2 Mon May 21 21:48:33 2018
35 t1 Mon May 21 21:48:34 2018
36 t2 Mon May 21 21:48:34 2018
37 t3 Mon May 21 21:48:35 2018
38 t3 Mon May 21 21:48:36 2018
39 t3 Mon May 21 21:48:37 2018
40 t3 Mon May 21 21:48:38 2018
41 t3 Mon May 21 21:48:39 2018
42 end-----
    协程池(gevent.pool)
     1 #coding:utf8
 2 import threading
 3 import time
 4 
 5 class make_baozi(threading.Thread):
 6     def __init__(self, id, sem):
 7         super(make_baozi,self).__init__()
 8         self.url = id
 9         self.sem = sem
10 
11     def run(self):
12         time.sleep(2)
13         print("make a baozi")
14         self.sem.release() # 内部维护的计数器加1，并通知内部维护的conditon通知acquire
15 
16 class eat_baozi(threading.Thread):
17     def __init__(self, sem):
18         super(eat_baozi,self).__init__()
19         self.sem = sem
20 
21     def run(self):
22         for i in range(20):
23             self.sem.acquire() # 内部维护的计数器减1，到0就会阻塞
24             make_thread = make_baozi(i,sem)
25             make_thread.start()
26             print('eat maozi %s'%i)
27 
28 if __name__ == '__main__':
29     sem = threading.Semaphore(3) #设置同时最多3个
30     url_producer = eat_baozi(sem)
31     url_producer.start()
32 
33 
34 
35 #结果3个一出
36 eat maozi 3
37 eat maozi 4
38 eat maozi 5
39 make a baozi
40 make a baozi
41 make a baozi
    线程间同步--信号量

    技术对比：

    总结：I/O密集的场景下尽量使用协程来完成任务
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  • 原文地址：https://www.cnblogs.com/cx59244405/p/9069667.html
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