命令
ab -n 10000 -c 100 http://aso100.com/index.php/rank
-n：代表请求数
-c：代表并发数
-H：添加请求头，例如 ‘Accept-Encoding: gzip’，以gzip方式请求。
-n 10000 -c 100 即一共进行10000次请求，每次并发数为100.
结果
[root@a2 ~]# ab -n 10000 -c 200 http://aso100.com/
This is ApacheBench, Version 2.3 <$Revision: 655654 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking aso100.com (be patient)
Completed 1000 requests
Completed 2000 requests
Completed 3000 requests
Completed 4000 requests
Completed 5000 requests
Completed 6000 requests
Completed 7000 requests
Completed 8000 requests
Completed 9000 requests
Completed 10000 requests
Finished 10000 requests
Server Software: nginx/1.6.3
Server Hostname: aso100.com
Server Port: 80
Document Path: /
Document Length: 6299 bytes
Concurrency Level: 200
Time taken for tests: 19.562 seconds
Complete requests: 10000
Failed requests: 9
(Connect: 0, Receive: 0, Length: 9, Exceptions: 0)
Write errors: 0
Non-2xx responses: 9
Total transferred: 66722805 bytes
HTML transferred: 62934857 bytes
#吞吐率，计算公式：Complete requests / Time taken for tests
Requests per second: 511.19 [#/sec] (mean)
#用户平均请求等待时间，Time taken for tests /Complete requests
Time per request: 391.241 [ms] (mean)
#服务器平均请求等待时间，Time taken for tests / (Complete requests /Concurrency Level)
Time per request: 1.956 [ms] (mean, across all concurrent requests)
Transfer rate: 3330.89 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 110 512.1 0 15000
Processing: 10 268 139.6 248 4640
Waiting: 7 268 139.6 248 4640
Total: 59 378 570.0 250 16715
Percentage of the requests served within a certain time (ms)
50% 250 ## 50%的请求在250ms内返回
66% 260 ## 60%的请求在260ms内返回
75% 275
80% 290
90% 375
95% 1249
98% 1304
99% 2641
100% 16715 (longest request)
