python多线程处理重复任务10000次

#!/usr/bin/python
import threading
import urllib2
#f = open("/root/wget.txt","a")
x = [ i.strip() for i in open("/root/ceshi/abc.txt","r") ]
#f1 = open("/root/abc.txt","r")
def wget(x):
response = urllib2.urlopen("http://abc.abc.com/organize/domain/allupdate?domainname=%s"%x)
if  response.read() == '{"code": "0", "data": "ok"}':
f.write('%s {"code": "0", "data": "ok"}\n'%x)
else:
f.write('%s {"code": "0", "data": "fail"}\n'%x)
def main():
n = 0
while len(x) - n >= 20:
f = open("/root/ceshi/wget.txt","a")
threads = []
for i in range(n+0,n+20):
t = threading.Thread(target=wget,args=(x[i],))
threads.append(t)
for i in range(20):
threads[i].start()
for i in range(20):
threads[i].join()
n+=20
f.close()
f = open("/root/ceshi/wget.txt","a")
for i in range(n,len(x)):
threads = []
t = threading.Thread(target=wget,args=(x[i]))
threads.append(t)
for i in range(len(x)-n):
threads[i].start()
for i in range(len(x)-n):
threads[i].join()
f.close()
if __name__ == '__main__':
main()