freebsd6.1+apache2.2下使用ab出错

ilang

我装的是6.1-beat4+apache2.2，服务器正常使用，但是每次使用ab测试时就出现如下错误：
/usr/local/sbin/ab -n 10000 -c 100 http://localhost/
This is ApacheBench, Version 2.0.40-dev <$Revision: 1.146 $> apache-2.0
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Copyright 1997-2005 The Apache Software Foundation, http://www.apache.org/

Benchmarking localhost (be patient)
apr_poll: The timeout specified has expired (70007)

用google和baidu搜了，找不到答案。请各位大大帮帮忙