进程

 1 #!/usr/bin/env python
 2 #coding:utf-8
 3 
 4 from multiprocessing import Pool
 5 
 6 def f(x):
 7     return x*x
 8 
 9 if __name__ == '__main__':
10     p = Pool(5)
11     print(p.map(f, [1, 2, 3]))
12 
13 
14 #直接起了三个进程，多进程

 子进程与父进程的关系
 1 #!/usr/bin/env python
 2 #coding:utf-8
 3 
 4 from multiprocessing import Process
 5 import os
 6 
 7 def info(title):
 8     print title
 9     print 'module name:', __name__
10     if hasattr(os, 'getppid'):  # only available on Unix
11         print 'parent process:', os.getppid()
12     print 'process id:', os.getpid()
13 
14 def f(name):
15     info('function f')
16     print 'hello', name
17 
18 if __name__ == '__main__':
19     info('main line')#此时是父进程
20     p = Process(target=f, args=('bob',))#这边是调用的子进程
21     p.start()
22     p.join()

进程锁
 1 #!/usr/bin/env python
 2 #coding:utf-8
 3 
 4 from multiprocessing import Process, Lock
 5 
 6 def f(l, i):
 7     l.acquire()
 8     print 'hello world', i
 9     l.release()
10 
11 if __name__ == '__main__':
12     lock = Lock()
13 
14     for num in range(10):
15         Process(target=f, args=(lock, num)).start()

进程之间的通信

 1 #!/usr/bin/env python
 2 #coding:utf-8
 3 
 4 '''
 5 from multiprocessing import Process, Queue#这个Queue跟直接import Queue不一样
 6 
 7 def f(q):
 8     q.put([42, None, 'hello'])
 9 
10 if __name__ == '__main__':
11     q = Queue()
12     p = Process(target=f, args=(q,))
13     p.start()
14     print q.get()    # prints "[42, None, 'hello']"
15     p.join()
16 
17 
18 #共享数据
19 
20 '''
21 
22 from multiprocessing import Process,Queue
23 
24 
25 def f(q,n):
26     q.put([n,'hello'])
27 
28 
29 if __name__ == '__main__':
30     q = Queue()
31     for i in range(5):
32         p = Process(target=f,args=(q,i))
33         p.start()
34 
35     while True:
36         print q.get()
37 
38 
39 #将数据都保存一个一个队列中（Queue）

进程之间内存共享value,array

 1 #!/usr/bin/env python
 2 #coding:utf-8
 3 
 4 from multiprocessing import Process, Value, Array
 5 
 6 def f(n, a):
 7     n.value = 3.1415927
 8     for i in range(len(a)):
 9         a[i] = -a[i]
10 
11 if __name__ == '__main__':
12     num = Value('d', 0.0)
13     arr = Array('i', range(10))
14 
15     p = Process(target=f, args=(num, arr))
16     p.start()
17     p.join()
18 
19     print num.value
20     print arr[:]
21 
22 
23 #数据和列表级别的数据共享

使用较多的内存共享

 1 #!/usr/bin/env python
 2 #coding:utf-8
 3 
 4 from multiprocessing import Process, Manager
 5 
 6 def f(d, l):
 7     d[1] = '1'
 8     d['2'] = 2
 9     d[0.25] = None
10     l.reverse()
11 
12 if __name__ == '__main__':
13     manager = Manager()
14 
15     d = manager.dict()
16     l = manager.list(range(10))
17 
18     p = Process(target=f, args=(d, l))
19     p.start()
20     p.join()
21 
22     print d
23     print l
24 
25 
26 #进程之间的内存共享不是真正的内存共享，是通过一个中间通道来进行共享，线程才是真正的共享，support types list, dict, Namespace, Lock, RLock, Semaphore, BoundedSemaphore, Condition, Event, Queue, Value and Array