多线程使用例程及Ctrl+C结束多线程

#!/usr/bin/env python
#coding: utf-8
import time, threading
import random
import socket
import signal

HOST = '192.168.1.110'
UDPPORT = 8888
address = (HOST, UDPPORT)
thread_num = 5  #open thread num
sendto_time = 1 #sendto sleep time
is_exit = True
start_time = 0
thread_count = range(0,thread_num)

def SendToData(sock,address,str):
    sock.sendto(str,address)

def clientThread(arg,val):
    sock = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
    count = 0
    while is_exit:
        count += 1
        global thread_count
        thread_count[arg] = count
        str = 'index:%d count:%d' % (arg, count)
        SendToData(sock, address, str)
        print '[%d:%d]Sendto ...\n' % (arg, count)
        time.sleep(sendto_time)
    sock.close()

ncli = range(0,thread_num)
threads = []
def press_test():
    try:
        for i in ncli:
            t = threading.Thread(target=clientThread, args=(i,0))
            t.setDaemon(True)
            threads.append(t)
        for i in ncli:
            threads[i].start()
        #for i in ncli:
        #    threads[i].join()
    except KeyboardInterrupt:
        print 'end'
def signal_handler(signum, frame):
    tatol_count = 0
    time_count = int(time.time() - start_time)
    global is_exit
    is_exit = False
    time.sleep(1)
    print '\n***********Test Result**********'
    for i,val in enumerate(thread_count):
        tatol_count += val
        print 'index:%d count:%d' % (i,val)
    print 'Press test time:%ds' % (time_count)
    print 'Press test tatol count:%d' % (tatol_count)
    if time_count > 0:
        print 'Press test average second num:%d' % (tatol_count/time_count)
    print '*************************************\n\n\n'

if __name__ == '__main__':
    global start_time
    start_time = time.time()
    signal.signal(signal.SIGINT, signal_handler)
    signal.signal(signal.SIGTERM, signal_handler)
    press_test()
    while True:
        alive = False
        for i in ncli:
            alive = alive or threads[i].isAlive()
            time.sleep(0.01)
        if not alive:
            break