python学习之多线程(二)

使用multiprocessing

使用multiprocessing.dummy

单使用multiprocessing模块的指的是多进程，使用multiprocessing.dummy则表示使用的是多线程

# from multiprocessing import Pool
from multiprocessing.dummy import Pool as ThreadPool
from multiprocessing import cpu_count
import time
import urllib2

urls = [
    'http://www.baidu.com',
    'http://home.baidu.com/',
    'http://tieba.baidu.com/',
    'http://zhidao.baidu.com/',
    'http://music.baidu.com/',
    'http://image.baidu.com/',
    'http://python-china.org/',
    'http://python-china.org/node/about',
    'http://python-china.org/node/',
    'http://python-china.org/account/signin',
    'http://python-china.org/account/signup',
    'http://www.qq.com',
    'http://www.youku.com',
    'http://www.tudou.com'
]

start = time.time()
results = map(urllib2.urlopen, urls)
print 'Normal:', time.time() - start

start2 = time.time()
# 开cpu_count个 worker，没有参数时默认是 cpu 的核心数
pool = ThreadPool(processes=cpu_count)
# 在线程中执行 urllib2.urlopen(url) 并返回执行结果
results2 = pool.map(urllib2.urlopen, urls)
pool.close()
pool.join()
print 'Thread Pool:', time.time() - start2