#练习:
import time
from multiprocessing import Pool
def run(fn):
#fn: 函数参数是数据列表的一个元素
time.sleep(1)
return fn * fn if __name__ == "__main__":
testFL = [1,2,3,4,5,6]
print 'Single process execution sequence:' #顺序执行(也就是串行执行,单进程)
s = time.time()
for fn in testFL:
run(fn) e1 = time.time()
print u"顺序执行时间:", int(e1 - s) print 'concurrent:' #创建多个进程,并行执行
pool = Pool(5) #创建拥有5个进程数量的进程池
#testFL:要处理的数据列表,run:处理testFL列表中数据的函数
rl =pool.map(run, testFL)
pool.close()#关闭进程池,不再接受新的任务
pool.join()#主进程阻塞等待子进程的退出
e2 = time.time()
print u"并行执行时间:", int(e2 - e1)
print rl #练习:
from multiprocessing import Process, Queue
import os, time, random # 写数据进程执行的代码:
def write(q):
for value in ['A', 'B', 'C']:
print 'Put %s to queue...' % value
q.put(value)
time.sleep(random.random()) # 读数据进程执行的代码
def read(q):
time.sleep(1)
while not q.empty():
# if not q.empty():
print 'Get %s from queue.' % q.get(True)
time.sleep(1) # 目的是等待写队列完成 if __name__=='__main__':
# 父进程创建Queue,并传给各个子进程
q = Queue()
pw = Process(target = write, args = (q,))
pr = Process(target = read, args = (q,))
# 启动子进程pw,写入:
pw.start()
# 启动子进程pr,读取:
pr.start()
# 等待pw结束:
pw.join()
pr.join()
print “Done!”