如何验证 localhost 上的 DNS 缓存已经生效了？

linux 上可以用 nscd 做 DNS 缓存，想验证一下效果，就写了个简单的脚本

dns.py

import socket
i = 0;
while i < 1000:
   	i+=1;
   	ip = socket.gethostbyname("taobao.com")

然后通过 time python dns.py 来执行

[root@host ~]# time python dns.py

real   	0m2.350s
user   	0m0.045s
sys    	0m0.058s
[root@host ~]# service nscd start
Starting nscd:                                             [  OK  ]
[root@host ~]# time python dns.py

real   	0m2.453s
user   	0m0.040s
sys    	0m0.057s

nscd 的配置如下

[root@host ~]# cat /etc/nscd.conf
#logfile        /var/log/nscd.log
threads         6
max-threads     128
server-user     nscd
debug-level     5
paranoia        no
enable-cache    passwd      no
enable-cache    group       no
enable-cache    hosts       yes
positive-time-to-live   hosts   5
negative-time-to-live   hosts       20
suggested-size  hosts       211
check-files     hosts       yes
persistent      hosts       yes
shared          hosts       no
max-db-size     hosts       33554432

对比下来，好像没有起到什么效果