Apache AB 压力测试 
安装

// 安装工具 yum install httpd-tools

使用

// URL 是网站请求路径 ab -c 1000 -n 2000 "http://www.baidu.com"

c 并发量
n 请求数

结果示例：

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 shop-app-envelope.mall.fenfenriji.com (be patient)
Completed 200 requests
Completed 400 requests
Completed 600 requests
Completed 800 requests
Completed 1000 requests
Completed 1200 requests
Completed 1400 requests
Completed 1600 requests
Completed 1800 requests
Completed 2000 requests
Finished 2000 requestsServer Software:        nginx
Server Hostname:        shop-app-envelope.mall.fenfenriji.com
Server Port:            80Document Path:          /envelope/data?enkey=d0hyf1or&uid=4040400&expires=1437460116&token=0f2aef4192f5374f85f844134ad14df5  #URL中的根绝对路径
Document Length:        138 bytes  #HTTP响应数据的正文长度Concurrency Level:      1000   #并发用户数
Time taken for tests:   9.087 seconds  #所有这些请求被处理完成所花费的总时间
Complete requests:      2000 #总请求数量，这是我们设置的参数之一
Failed requests:        0  #失败的请求数量
Write errors:           0
Total transferred:      776000 bytes   #所有请求的响应数据长度总和
HTML transferred:       276000 bytes   #所有请求的响应数据中正文数据的总和
Requests per second:    220.10 [#/sec] (mean)     #吞吐率，计算公式：Complete requests / Time taken for tests
Time per request:       4543.349 [ms] (mean)      #用户平均请求等待时间，计算公式：Time token for tests/（Complete requests/Concurrency Level）
Time per request:       4.543 [ms] (mean, across all concurrent requests)  #服务器平均请求等待时间，计算公式：Time taken for tests/Complete requests，正好是吞吐率的倒数。也可以这么统计：Time per request/Concurrency Level
Transfer rate:          83.40 [Kbytes/sec] received   #表示这些请求在单位时间内从服务器获取的数据长度，计算公式：Total trnasferred/ Time taken for tests，这个统计很好的说明服务器的处理能力达到极限时，其出口宽带的需求量。Connection Times (ms)  min  mean[+/-sd] median   max
Connect:        2   44  54.9     16     186
Processing:  2069 3977 1830.1   4365    6841
Waiting:     2069 3977 1830.1   4365    6841
Total:       2071 4020 1879.2   4383    6982Percentage of the requests served within a certain time (ms)  50%   438366%   539775%   587880%   616390%   657895%   678598%   690399%   6949100%   6982 (longest request)
#整个场景中所有请求的响应情况。在场景中每个请求都有一个响应时间，其中50％的用户响应时间小于4383毫秒，60％ 的用户响应时间小于5397毫秒，最大的响应时间小于6982毫秒