进程

#!/usr/bin/env python
#coding:utf-8

from multiprocessing import Pool

def f(x):
    return x*x

if __name__ == '__main__':
    p = Pool(5)
    print(p.map(f, [1, 2, 3]))


#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
#coding:utf-8

from multiprocessing import Process
import os

def info(title):
    print title
    print 'module name:', __name__
    if hasattr(os, 'getppid'):  # only available on Unix
        print 'parent process:', os.getppid()
    print 'process id:', os.getpid()

def f(name):
    info('function f')
    print 'hello', name

if __name__ == '__main__':
    info('main line')#此时是父进程
    p = Process(target=f, args=('bob',))#这边是调用的子进程
    p.start()
    p.join()

进程锁
 1 #!/usr/bin/env python
#coding:utf-8

from multiprocessing import Process, Lock

def f(l, i):
    l.acquire()
    print 'hello world', i
    l.release()

if __name__ == '__main__':
    lock = Lock()

    for num in range(10):
        Process(target=f, args=(lock, num)).start()

进程之间的通信

#!/usr/bin/env python
#coding:utf-8

'''
from multiprocessing import Process, Queue#这个Queue跟直接import Queue不一样

def f(q):
    q.put([42, None, 'hello'])

if __name__ == '__main__':
    q = Queue()
    p = Process(target=f, args=(q,))
    p.start()
    print q.get()    # prints "[42, None, 'hello']"
    p.join()


#共享数据

'''

from multiprocessing import Process,Queue


def f(q,n):
    q.put([n,'hello'])


if __name__ == '__main__':
    q = Queue()
    for i in range(5):
        p = Process(target=f,args=(q,i))
        p.start()

    while True:
        print q.get()


#将数据都保存一个一个队列中（Queue）

进程之间内存共享value,array

#!/usr/bin/env python
#coding:utf-8

from multiprocessing import Process, Value, Array

def f(n, a):
    n.value = 3.1415927
    for i in range(len(a)):
        a[i] = -a[i]

if __name__ == '__main__':
    num = Value('d', 0.0)
    arr = Array('i', range(10))

    p = Process(target=f, args=(num, arr))
    p.start()
    p.join()

    print num.value
    print arr[:]


#数据和列表级别的数据共享

使用较多的内存共享

#!/usr/bin/env python
#coding:utf-8

from multiprocessing import Process, Manager

def f(d, l):
    d[1] = '1'
    d['2'] = 2
    d[0.25] = None
    l.reverse()

if __name__ == '__main__':
    manager = Manager()

    d = manager.dict()
    l = manager.list(range(10))

    p = Process(target=f, args=(d, l))
    p.start()
    p.join()

    print d
    print l


#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