concurrency - Rust vs Go 并发网络服务器，为什么 Rust 在这里很慢？

Question

我正在尝试对 multi-threaded webserver example 进行一些基准测试在 Rust 书中，为了进行比较，我在 Go 中构建了类似的东西，并使用 ApacheBench 运行了一个基准测试。尽管这是一个简单的例子，但差异太大了。执行相同操作的 Go Web 服务器快 10 倍。由于我期望 Rust 更快或处于同一水平，我尝试使用 futures 和 smol 进行多次修订(尽管我的目标是比较仅使用标准库的实现)但结果几乎相同。这里有人可以建议对 Rust 实现进行更改以在不使用大量线程的情况下使其更快吗？

这是我使用的代码:https://github.com/deepu105/concurrency-benchmarks

tokio-http 版本最慢，其他 3 个 rust 版本几乎相同

这里是基准:

Rust(8 个线程，100 个线程的数字更接近 Go):

❯ ab -c 100 -n 1000 http://localhost:8080/
This is ApacheBench, Version 2.3 <$Revision: 1879490 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking localhost (be patient)
Completed 100 requests
Completed 200 requests
Completed 300 requests
Completed 400 requests
Completed 500 requests
Completed 600 requests
Completed 700 requests
Completed 800 requests
Completed 900 requests
Completed 1000 requests
Finished 1000 requests


Server Software:        
Server Hostname:        localhost
Server Port:            8080

Document Path:          /
Document Length:        176 bytes

Concurrency Level:      100
Time taken for tests:   26.027 seconds
Complete requests:      1000
Failed requests:        0
Total transferred:      195000 bytes
HTML transferred:       176000 bytes
Requests per second:    38.42 [#/sec] (mean)
Time per request:       2602.703 [ms] (mean)
Time per request:       26.027 [ms] (mean, across all concurrent requests)
Transfer rate:          7.32 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    2   2.9      1      16
Processing:     4 2304 1082.5   2001    5996
Waiting:        0 2303 1082.7   2001    5996
Total:          4 2307 1082.1   2002    5997

Percentage of the requests served within a certain time (ms)
  50%   2002
  66%   2008
  75%   2018
  80%   3984
  90%   3997
  95%   4002
  98%   4005
  99%   5983
 100%   5997 (longest request)

开始:

ab -c 100 -n 1000 http://localhost:8080/
This is ApacheBench, Version 2.3 <$Revision: 1879490 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking localhost (be patient)
Completed 100 requests
Completed 200 requests
Completed 300 requests
Completed 400 requests
Completed 500 requests
Completed 600 requests
Completed 700 requests
Completed 800 requests
Completed 900 requests
Completed 1000 requests
Finished 1000 requests


Server Software:        
Server Hostname:        localhost
Server Port:            8080

Document Path:          /
Document Length:        174 bytes

Concurrency Level:      100
Time taken for tests:   2.102 seconds
Complete requests:      1000
Failed requests:        0
Total transferred:      291000 bytes
HTML transferred:       174000 bytes
Requests per second:    475.84 [#/sec] (mean)
Time per request:       210.156 [ms] (mean)
Time per request:       2.102 [ms] (mean, across all concurrent requests)
Transfer rate:          135.22 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    2   1.4      2       5
Processing:     0  203 599.8      3    2008
Waiting:        0  202 600.0      2    2008
Total:          0  205 599.8      5    2013

Percentage of the requests served within a certain time (ms)
  50%      5
  66%      7
  75%      8
  80%      8
  90%   2000
  95%   2003
  98%   2005
  99%   2010
 100%   2013 (longest request)

Answer 1

我只比较了你的“rustws”和 Go 版本。在 Go 中，你有无限的 goroutines(即使你将它们全部限制为只有一个 CPU 内核)，而在 rustws 中，你创建了一个具有 8 个线程的线程池。

由于您的请求处理程序每​​ 10 个请求休眠 2 秒，您将 rustws 版本限制为每秒 80/2 = 40 个请求，这就是您在 ab 结果中看到的。 Go 不会受到这种任意瓶颈的影响，因此它向您展示了它在单个 CPU 内核上的最大处理能力。