brew install wrk

make all

make test

make test -f Makefile2

➜  koa-benchmark git:(master) ✗ node -v
v4.0.0
➜  koa-benchmark git:(master) ✗ npm -v 
2.14.2
➜  koa-benchmark git:(master) ✗ npm test 
benchmark koa-1

  1 middleware
  5976.88

  5 middleware
  3495.61

  10 middleware
  5494.52

  15 middleware
  5444.90

  20 middleware
  5631.77

  30 middleware
  5091.48

  50 middleware
  3657.46

  100 middleware
  4712.93
  
benchmark koa-2

  1 middleware
  5959.41

  5 middleware
  5653.19

  10 middleware
  5652.32

  15 middleware
  5882.88

  20 middleware
  5929.52

  30 middleware
  5700.04

  50 middleware
  5852.57

  100 middleware
  5211.41

benchmark express

  1 middleware
  5500.16

  5 middleware
  5783.63

  10 middleware
  5561.32

  15 middleware
  5253.31

  20 middleware
  5305.64

  30 middleware
  4950.02

  50 middleware
  4472.47

  100 middleware
  4077.43
  

假设支持100w
每个用户每天访问a次 (web.tools.com)
每天次数：100w * a
按照80/20原则，80%的访问集中在20%的时间内
100w * a * 80%  / 4.8小时
假设对用户来说每次访问6秒钟是可以接受的
(100w*a*80%/4.8h)*6=测试用并发数据