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吞吐量相关计算公式推导 #4
Description
使用apachebench(mac 自带)进行一次压测：
ab -c30 -t6 http://127.0.0.1:3000/test输出如下：
This is ApacheBench, Version 2.3 <$Revision: 1843412 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/
Benchmarking 127.0.0.1 (be patient)
Completed 5000 requests
Finished 9201 requests
Server Software:
Server Hostname: 127.0.0.1
Server Port: 3000
Document Path: /test
Document Length: 40 bytes
Concurrency Level: 30
Time taken for tests: 6.000 seconds
Complete requests: 9201
Failed requests: 3
(Connect: 0, Receive: 0, Length: 3, Exceptions: 0)
Total transferred: 1821996 bytes
HTML transferred: 368237 bytes
Requests per second: 1533.46 [#/sec] (mean)
Time per request: 19.564 [ms] (mean)
Time per request: 0.652 [ms] (mean, across all concurrent requests)
Transfer rate: 296.54 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.2 0 16
Processing: 0 1 4.9 0 283
Waiting: 0 0 4.9 0 283
Total: 0 1 4.9 0 284
Percentage of the requests served within a certain time (ms)
50% 0
66% 1
75% 1
80% 1
90% 1
95% 1
98% 1
99% 1
100% 284 (longest request)
首先，挑出几个最容易理解的基本数据：
- 总任务数量 (num of request)
n = 9201 - 本次测试持续时间 (timelimit)
t = 6s - 平均并发数 (concurrency)
c = 30
下面进入推导：
-
每秒请求数（Requests/Queries per second,RPS/QPS）
-
累计处理时间
-
平均响应时间(Time per request，Response Time)
总结
TPS的计算方式和QPS一样，取决于c代表的意义。
公式大概就这几个，根据已知条件自行变换，例如：
(
平均并发数 = 平均响应时间 * 平均每秒请求数)
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