python 多线程ping大量服务器在线情况

需要ping一个网段所有机器的在线情况，shell脚步运行时间太长，用python写个多线程ping吧，代码如下：

#!/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()
'''

效果如下：

平一个网段只要2.7s左右，够快！！！