ab 是 Apache 附带的接口压力测试功能，非常简单易用。在测试服务端程序自身运行时长和跨区测试接口反馈时长时非常有用。
下载
CentOS
$ sudo yum install -y httpd
Ubuntu
$ sudo apt install -y apache2-utils
使用
$ ab -c 10 -n 100 http://ip-api.com/json
参数
-c: 表示并发数-n: 表示请求总数
结果
> $ ab -c 10 -n 100 http://ip-api.com/json
This is ApacheBench, Version 2.3 <$Revision: 1807734 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking ip-api.com (be patient).....done
Server Software:
Server Hostname: ip-api.com
Server Port: 80
Document Path: /json
Document Length: 306 bytes
Concurrency Level: 10
Time taken for tests: 6.184 seconds
Complete requests: 100
Failed requests: 0
Total transferred: 46200 bytes
HTML transferred: 30600 bytes
Requests per second: 16.17 [#/sec] (mean)
Time per request: 618.369 [ms] (mean)
Time per request: 61.837 [ms] (mean, across all concurrent requests)
Transfer rate: 7.30 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 1 3 1.1 3 6
Processing: 528 572 58.4 550 889
Waiting: 528 571 58.7 549 888
Total: 531 575 58.3 552 891
Percentage of the requests served within a certain time (ms)
50% 552
66% 565
75% 574
80% 600
90% 635
95% 656
98% 890
99% 891
100% 891 (longest request)结果详解
Server Software: web服务器软件及版本
Server Hostname: 请求的地址
Server Port: 请求的端口
Document Path: 请求的页面路径
Document Length: 页面大小
Concurrency Level: 并发数
Time taken for tests: 测试总共花费的时间
Complete requests: 完成的请求数
Failed requests: 失败的请求数
Write errors: 写入错误
Total transferred: 总共传输字节数，包含http的头信息等
HTML transferred: html字节数，实际的页面传递字节数
Requests per second: 每秒处理的请求数，服务器的吞吐量（重要）
Time per request: 平均数，用户平均请求等待时间
Time per request: 服务器平均处理时间
Transfer rate: 平均传输速率（每秒收到的速率）Time per request 是我们测试接口时长时非常关键的字段。
