ab

服务器负载太大而影响程序效率也是很常见的，Apache服务器自带有一个叫AB(ApacheBench)的工具，在bin目录下。使用这个轻巧的工具我们可以对服务器进行负载测试，

基本用法:

ab -n 全部请求数 -c 并发数 测试url


例:ab -n 1000 -c 50

得到结果类似于(后面颜色字为中文翻译):

Server Software:        Apache/2.0.55
Server Hostname:        localhost
Server Port:            80

Document Path:          /1.php
Document Length:        82522 bytes  #请求文档大小

Concurrency Level:      50           #并发数  
Time taken for tests:   92.76140 seconds #全部请求完成耗时
Complete requests:      10000          #全部请求数
Failed requests:        1974           #失败的请求
  (Connect: 0, Length: 1974, Exceptions: 0)
Write errors:           0
Total transferred:      827019400 bytes #总传输大小
HTML transferred:       825219400 bytes
Requests per second:    108.61 [#/sec] (mean) #每秒请求数(平均)
Time per request:       460.381 [ms] (mean) #每次并发请求时间(所有并发)
Time per request:       9.208 [ms] (mean, across all concurrent requests)                              #每一请求时间(并发平均)  
Transfer rate:          8771.39 [Kbytes/sec] received #传输速率

Connection Times (ms) #连接时间
             min  mean[+/-sd] median   max
Connect(#连接):        0    0   2.1      0      46
Processing(#处理):    31  458  94.7    438    1078
Waiting(#等待):       15  437  87.5    422     938
Total:         31  458  94.7    438    1078


其它参数:

-n requests     全部请求数
-c concurrency  并发数
-t timelimit    最传等待回应时间
-p postfile     POST数据文件
-T content-type POST Content-type
-v verbosity    How much troubleshooting info to print
-w              Print out results in HTML tables
-i              Use HEAD instead of GET
-x attributes   String to insert as table attributes
-y attributes   String to insert as tr attributes
-z attributes   String to insert as td or th attributes
-C attribute    加入cookie, eg. 'Apache=1234. (repeatable)
-H attribute    加入http头, eg. 'Accept-Encoding: gzip'
                Inserted after all normal header lines. (repeatable)
-A attribute    http验证,分隔传递用户名及密码
-P attribute    Add Basic Proxy Authentication, the attributes
                are a colon separated username and password.
-X proxy:port   代理服务器
-V              查看ab版本
-k              Use HTTP KeepAlive feature
-d              Do not show percentiles served table.
-S              Do not show confidence estimators and warnings.
-g filename     Output collected data to gnuplot format file.
-e filename     Output CSV file with percentages served
-h              Display usage information (this message)