python 多线程ping大量服务器在线情况

#!/usr/bin/python
#coding=utf-8
'''
Created on 2015-8-4
@author: Administrator
'''

import threading,subprocess
from time import ctime,sleep,time
import Queue

queue=Queue.Queue()

class ThreadUrl(threading.Thread):
def __init__(self,queue):
threading.Thread.__init__(self)
self.queue=queue

def run(self):
while True:
host=self.queue.get()
ret=subprocess.call('ping -c 1 -w 1 '+host,shell=True,stdout=open('/dev/null','w'))
if ret:
print "%s is down" % host
else:
print "%s is up" % host
self.queue.task_done()

def main():
for i in range(100):
t=ThreadUrl(queue)
t.setDaemon(True)
t.start()
for host in b:
queue.put(host)
queue.join()

a=[]
with open('ip.txt') as f:
for line in f.readlines():
a.append(line.split()[0])
#print a

b=['192.168.3.'+str(x) for x in range(1,254)] #ping 192.168.3 网段
start=time()
main()
print "Elasped Time:%s" % (time()-start)

#t2=threading.Thread(target=move,args=('fff',))
#threads.append(t2)

'''
for i in a:
print ctime()
ping(i)
sleep(1)

if __name__ == '__main__':
for t in range(len(a)):
#t.setDaemon(True)
threads[t].start()
#t.join()
print "All over %s" % ctime()
'''