Concurrent calls in Python

concurrent.py

import eventlet
import time
from eventlet.green import urllib2

urls = [
    "http://www.amazon.com/",
    "http://www.google.com/",
    "http://www.twitter.com/"
]

def fetch(url):
    print 'calling %s' % url
    start = time.time() * 1000
    res = urllib2.urlopen(url).read()
    end = time.time() * 1000
    print 'completed %(url)s in %(time)d' % {"url": url, "time": (end - start)}
    return res

pool = eventlet.GreenPool()

start = time.time() * 1000

for body in pool.imap(fetch, urls):
    print 'done'

end = time.time() * 1000
print 'total time: %d' % (end - start)