性能测试：
使用st对服务器程序分别在freebsd和windows（cygwin）下的运行情况进行测试(st相应的运行在freebsd和cygwin下)。
机器硬件条件：intel (r) celeron cpu 2.40ghz；256ddr，maxtor 80g。
1. freebsd 4.7环境：
/*****************************************************/
www# ./st -n 100 -c 20 192.168.1.7/123
this is servertest for my pngserver, version 1.0
copyright (c) 2004-2005 xiongbin xiong all rights reserved
hustxxb@hotmail.com
testing...
server hostname: 192.168.1.7
server port: 80
document path: /123
total requests: 100
concurrency level: 20
time taken for tests: 0.709739 seconds
complete requests: 100
failed requests: 0
total transferred: 35000 bytes
requests per second: 140.90 [#/sec] (mean)
time per request: 141.948 [ms] (mean)
time per request: 7.097 [ms] (mean, across all concurrent requests)
transfer rate: 48.16 [kbytes/sec] received
/*************************************************************/
2. windows xp (cygwin)环境：
/*****************************************************/
testing...this is servertest for my pngserver, version 1.0
copyright (c) 2004-2005 xiongbin xiong all rights reserved
hustxxb@hotmail.com
testing...
server hostname: 192.168.1.7
server port: 80
document path: /qwe
total requests: 50
concurrency level: 5
time taken for tests: 39.487579 seconds
complete requests: 50
failed requests: 0
total transferred: 7900 bytes
requests per second: 1.27 [#/sec] (mean)
time per request: 3948.758 [ms] (mean)
time per request: 789.752 [ms] (mean, across all concurrent requests)
transfer rate: 0.20 [kbytes/sec] received
/****************************************************/
当并发数为5时，程序正常。
/*****************************************************/
testing...this is servertest for my pngserver, version 1.0
copyright (c) 2004-2005 xiongbin xiong all rights reserved
hustxxb@hotmail.com
connect error
connect error
connect error
connect error
connect error
connect error
connect error
server hostname: 192.168.1.7
server port: 80
document path: /qwe
total requests: 50
concurrency level: 10
time taken for tests: 29.208741 seconds
complete requests: 43
failed requests: 7
total transferred: 6794 bytes
requests per second: 1.47 [#/sec] (mean)
time per request: 6792.730 [ms] (mean)
time per request: 679.273 [ms] (mean, across all concurrent requests)
transfer rate: 0.23 [kbytes/sec] received
/****************************************************/
当并发数为10时，程序出现连接失败情况。
/*****************************************************/
testing...this is servertest for my pngserver, version 1.0
copyright (c) 2004-2005 xiongbin xiong all rights reserved
hustxxb@hotmail.com
connect error
connect error
......
connect error
server hostname: 192.168.1.7
server port: 80
document path: /qwe
total requests: 100
concurrency level: 20
time taken for tests: 30.19982 seconds
complete requests: 54
failed requests: 46
