为什么Google Go的http服务器包不能同时处理超过5个请求？

huangapple
go评论117阅读模式
英文:

Google Go: Why does the http server package not serve more than 5 simultaneous requests?

问题

我正在尝试使用Google的Go语言编写一个小型的HTTP服务器，以便以后进行扩展。我正在使用Windows上的Go（MinGw编译版本）。

在这种语言中，这是相当容易的，因为它已经有了必要的包：

  1. package main
  3. import (
  4. 	"http"
  5. 	"io"
  6. 	"os"
  7. 	"fmt"
  8. 	"strconv"
  9. )  
  12. func FileTest(w http.ResponseWriter, req *http.Request) {
  13. 	w.Header().Add("Content-Type", "image/jpeg")
  14. 	w.Header().Add("Content-Disposition", "inline; filename=image.jpg")
  15.     inName := "d:\\googlego\\somepic.jpg"
  16.     inFile, inErr := os.OpenFile(inName, os.O_RDONLY, 0666)
  17.     if inErr == nil {
  18.     	inBufLen := 16
  19.     	inBuf := make([]byte, inBufLen)
  20.     	
  21.     	_, inErr := inFile.Read(inBuf)
  22.     	for inErr == nil {
  23.     		w.Write(inBuf)
  24.     		_, inErr = inFile.Read(inBuf)
  25.     	} 
  26.     }
  27.     inErr = inFile.Close() 
  28.     
  29. }
  31. func MainPage(w http.ResponseWriter, req *http.Request) {
  32. 	io.WriteString(w, "Hi, download here: <a href=\"/FileTest\">HERE</a>")
  33. 	
  34. }
  37. func main() {
  38. 	fmt.Print("Port: ")
  39. 	var hi int 
  40. 	fmt.Scanf("%d", &hi)
  41. 	http.HandleFunc("/FileTest", FileTest)
  42. 	http.HandleFunc("/", MainPage)
  43. 	
  44. 	err := http.ListenAndServe("0.0.0.0:" + strconv.Itoa(hi), nil)
  45. 	
  46. 	if err != nil {
  47. 		fmt.Print(err) 
  48. 		fmt.Print((hi))
  49. 	}
  50. }

这将启动一个服务器，提供一个主页和一个从图像下载。两者都工作得非常好，我从ab（Apache基准测试工具）中得到了非常好的结果，最多可以同时处理6个线程：

  1. > ab -n 10000 -c 6 http://localhost:8080/
  2. Concurrency Level:      6
  3. Time taken for tests:   1.678096 seconds
  4. Complete requests:      10000
  6. Percentage of the requests served within a certain time (ms)
  7.   50%      1
  8.   66%      1
  9.   75%      1
  10.   80%      1
  11.   90%      2
  12.   95%      2
  13.   98%      2
  14.   99%      2
  15.  100%      3 (longest request)

当并发级别设置得更高时，情况如下：

  1. > ab -n 1000 -c 7 http://localhost:8080/
  2. Concurrency Level:      7
  3. Time taken for tests:   10.239586 seconds
  4. Complete requests:      1000
  6. Percentage of the requests served within a certain time (ms)
  7.   50%      1
  8.   66%      2
  9.   75%      2
  10.   80%      3
  11.   90%    499
  12.   95%    505
  13.   98%    507
  14.   99%    507
  15.  100%    510 (longest request)

请注意，这次我只进行了1,000个请求，但时间几乎增加了6倍。

这两个基准测试甚至还没有请求文件。

我对Go还不是很了解，但似乎Go运行时没有创建足够的操作系统线程来放置goroutine，或者类似的情况？

编辑：我下载了2011年10月7日的新版本r60.2。

现在情况变得更糟了：

  1. > ab -c 7 -n 1000 http://localhost:8080/
  2. Concurrency Level:      7
  3. Time taken for tests:   12.622722 seconds
  4. Complete requests:      1000
  5. Percentage of the requests served within a certain time (ms)
  6.   50%      1
  7.   66%      1
  8.   75%      2
  9.   80%      2
  10.   90%    496
  11.   95%    503
  12.   98%    506
  13.   99%    506
  14.  100%    507 (longest request)
英文:

I'm trying to code a small http server for later extension in Google's Go language. I am using Go on Windows (MinGw compiled version).

This is quite easy in this language since it already has the necessary package:

  1. package main
  3. import (
  4. 	&quot;http&quot;
  5. 	&quot;io&quot;
  6. 	&quot;os&quot;
  7. 	&quot;fmt&quot;
  8. 	&quot;strconv&quot;
  9. )  
  12. func FileTest(w http.ResponseWriter, req *http.Request) {
  13. 	w.Header().Add(&quot;Content-Type&quot;, &quot;image/jpeg&quot;)
  14. 	w.Header().Add(&quot;Content-Disposition&quot;, &quot;inline; filename=image.jpg&quot;)
  15.     inName := &quot;d:\\googlego\\somepic.jpg&quot;;
  16.     inFile, inErr := os.OpenFile(inName, os.O_RDONLY, 0666);
  17.     if inErr == nil {
  18.     	inBufLen := 16;
  19.     	inBuf := make([]byte, inBufLen);
  20.     	
  21.     	_, inErr := inFile.Read(inBuf);
  22.     	for inErr == nil {
  23.     		w.Write(inBuf)
  24.     		_, inErr = inFile.Read(inBuf);
  25.     	} 
  26.     }
  27.     inErr = inFile.Close(); 
  28.     
  29. }
  31. func MainPage(w http.ResponseWriter, req *http.Request) {
  32. 	io.WriteString(w, &quot;Hi, download here: &lt;a href=\&quot;/FileTest\&quot;&gt;HERE&lt;/a&gt;&quot;)
  33. 	
  34. }
  37. func main() {
  38. 	fmt.Print(&quot;Port: &quot;)
  39. 	var hi int 
  40. 	fmt.Scanf(&quot;%d&quot;, &amp;hi)
  41. 	http.HandleFunc(&quot;/FileTest&quot;, FileTest)
  42. 	http.HandleFunc(&quot;/&quot;, MainPage)
  43. 	
  44. 	err := http.ListenAndServe(&quot;0.0.0.0:&quot; + strconv.Itoa(hi), nil)
  45.  	
  46. 	if err != nil {
  47. 		fmt.Print(err) 
  48. 		fmt.Print((hi))
  49. 	}
  50. }

This starts a server that serves a main page and a download from an image. Both work very well and I get very good results from ab (Apache benchmark) up to 6 concurrent threads:

  1. &gt; ab -n 10000 -c 6 http://localhost:8080/
  2. Concurrency Level:      6
  3. Time taken for tests:   1.678096 seconds
  4. Complete requests:      10000
  6. Percentage of the requests served within a certain time (ms)
  7.   50%      1
  8.   66%      1
  9.   75%      1
  10.   80%      1
  11.   90%      2
  12.   95%      2
  13.   98%      2
  14.   99%      2
  15.  100%      3 (longest request)

When the concurrency level is set higher, this happens:

  1. &gt;ab -n 1000 -c 7 http://localhost:8080/
  2. Concurrency Level:      7
  3. Time taken for tests:   10.239586 seconds
  4. Complete requests:      1000
  6. Percentage of the requests served within a certain time (ms)
  7.   50%      1
  8.   66%      2
  9.   75%      2
  10.   80%      3
  11.   90%    499
  12.   95%    505
  13.   98%    507
  14.   99%    507
  15.  100%    510 (longest request)

Note that I only made 1'000 requests this time and it still took almost 6 times as much time.

Both benchmarks don't even request the file yet.

I don't know a lot about Go yet, but it seems that the Go runtime doesn't create enough OS threads to put the goroutines on, or something like that?

EDIT: I downloaded the new r60.2 from 07.10.2011.

Now it went even worse:

  1. &gt;ab -c 7 -n 1000 http://localhost:8080/
  2. Concurrency Level:      7
  3. Time taken for tests:   12.622722 seconds
  4. Complete requests:      1000
  5. Percentage of the requests served within a certain time (ms)
  6.   50%      1
  7.   66%      1
  8.   75%      2
  9.   80%      2
  10.   90%    496
  11.   95%    503
  12.   98%    506
  13.   99%    506
  14.  100%    507 (longest request)

答案1

得分: 4

截至今天（2011年9月），Go语言在Windows平台上的移植仍在进行中。它在一些重要的方面，包括稳定性和性能（尽管每天都在改进），落后于其他支持的平台（如Linux等）。我建议您在64位Linux平台上进行测试，看看它与Windows平台有何不同，然后也许您可以开始分析在Windows下出了什么问题。

英文:

As of today (Sep 2011) the Windows port of Go is a work-in-progress. It lags behind the other supported platforms (Linux, etc.) in some important measures including stability and performance (though it is improving every day). I would suggest that you try your test on a 64-bit Linux platform, and see how it differs, then maybe you can start deconstructing what's going wrong under Windows.

答案2

得分: 2

我刚刚在Go 64位的tip上尝试了这个基准测试，并得到了以下结果（在Core 2 Duo 2GHz，Windows 7 x64上）：

  1. C:\Program Files (x86)\Apache Software Foundation\Apache2.2\bin&gt;ab -c 7 -n 1000 http://localhost:8080/
  2. 并发级别：7
  3. 测试所用时间：0.458秒
  4. 完成请求数：1000
  5. 在特定时间内完成请求的百分比（毫秒）
  6.   50%      3
  7.   66%      3
  8.   75%      3
  9.   80%      3
  10.   90%      4
  11.   95%      5
  12.   98%      7
  13.   99%      8
  14.  100%      9（最长的请求）
英文:

I just tried this benchmark with Go 64-bit at tip, and got the following results (on a Core 2 Duo 2GHz, Windows 7 x64):

  1. C:\Program Files (x86)\Apache Software Foundation\Apache2.2\bin&gt;ab -c 7 -n 1000 http://localhost:8080/
  2. Concurrency Level:      7
  3. Time taken for tests:   0.458 seconds
  4. Complete requests:      1000
  5. Percentage of the requests served within a certain time (ms)
  6.   50%      3
  7.   66%      3
  8.   75%      3
  9.   80%      3
  10.   90%      4
  11.   95%      5
  12.   98%      7
  13.   99%      8
  14.  100%      9 (longest request)

huangapple
  • 本文由 发表于 2011年9月28日 02:20:05
  • 转载请务必保留本文链接：https://go.coder-hub.com/7573850.html
  • go
  • http
  • httpserver
  • windows
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