AB 测试 Gunicorn 时 Failed requests 数量惊人是怎么回事？

[xchange]

$ ab -n 10000 -c 100 http://127.0.0.1:8000/random

Server Software: gunicorn/19.4.5

Server Hostname: 127.0.0.1

Server Port: 8000

Document Path: /random

Document Length: 12379 bytes

Concurrency Level: 100

Time taken for tests: 17.068 seconds

Complete requests: 10000

Failed requests: 9790 # 大部分请求都失败了？

(Connect: 0, Receive: 0, Length: 9790, Exceptions: 0)

Total transferred: 125432017 bytes

HTML transferred: 123732017 bytes # 从传输的数据量来看好像又没问题，差不多正好是 1 万个请求应该传输的字节数

Requests per second: 585.91 [#/sec] (mean)

Time per request: 170.676 [ms] (mean)

Time per request: 1.707 [ms] (mean, across all concurrent requests)

Transfer rate: 7176.89 [Kbytes/sec] received