最大并发 HttpWebRequests 数 [英] Max number of concurrent HttpWebRequests
问题描述
我正在对一个 Web 应用进行压力测试，并设置了一个 Windows 测试程序，该程序启动多个线程并对每个线程发出一个 Web 请求.
I'm stress testing a web app and have set up a windows test program that spins up a number of threads and sends out a web request on each one.
问题是我得到以下输出:
Problem is I get the following output:
01/09/09 11:34:04 Starting new HTTP request on 10
01/09/09 11:34:04 Starting new HTTP request on 11
01/09/09 11:34:04 Starting new HTTP request on 13
01/09/09 11:34:05 Starting new HTTP request on 14
01/09/09 11:34:05 Starting new HTTP request on 11
01/09/09 11:34:05 11 has finished!
01/09/09 11:34:05 Starting new HTTP request on 13
01/09/09 11:34:05 13 has finished!
01/09/09 11:34:05 Starting new HTTP request on 14
01/09/09 11:34:05 14 has finished!
01/09/09 11:34:05 Starting new HTTP request on 11
01/09/09 11:34:05 11 has finished!
01/09/09 11:34:05 Starting new HTTP request on 14
01/09/09 11:34:05 14 has finished!
01/09/09 11:34:05 Starting new HTTP request on 13
01/09/09 11:34:05 13 has finished!
01/09/09 11:34:05 Starting new HTTP request on 15
01/09/09 11:34:06 Starting new HTTP request on 11
01/09/09 11:34:06 11 has finished!
01/09/09 11:34:06 Starting new HTTP request on 14
01/09/09 11:34:06 14 has finished!
哪种看起来最多有 5 个线程，即使我创建了 100 个:
which sort of looks like there's a maximum of 5 threads, even if I create 100 as so:
int numberOfThreads = Convert.ToInt32(txtConcurrentThreads.Text);
List<BackgroundWorker> workers = new List<BackgroundWorker>();
for (int N = 0; N < numberOfThreads; N++)
{
BackgroundWorker worker = new BackgroundWorker();
worker.DoWork += new DoWorkEventHandler(worker_DoWork);
worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
workers.Add(worker);
}
foreach(BackgroundWorker worker in workers)
{
worker.RunWorkerAsync();
}
谁能告诉我发生了什么?
Can anyone enlighten me as to what is going on?
谢谢
如果按照建议我睡了 5 秒钟，而不是 httpwebrequest，那么我确实会触发更多线程，但没有我预期的那么多:
If as suggested I sleep for 5 seconds, instead of httpwebrequest, then I do get more threads firing but not as many as I would have expected:
01/09/09 11:56:14 Starting new HTTP request on 7
01/09/09 11:56:14 Starting new HTTP request on 11
01/09/09 11:56:15 Starting new HTTP request on 12
01/09/09 11:56:15 Starting new HTTP request on 13
01/09/09 11:56:16 Starting new HTTP request on 14
01/09/09 11:56:16 Starting new HTTP request on 15
01/09/09 11:56:17 Starting new HTTP request on 16
01/09/09 11:56:17 Starting new HTTP request on 17
01/09/09 11:56:18 Starting new HTTP request on 18
01/09/09 11:56:19 Starting new HTTP request on 7
01/09/09 11:56:19 7 has finished!
01/09/09 11:56:19 Starting new HTTP request on 11
01/09/09 11:56:19 11 has finished!
01/09/09 11:56:19 Starting new HTTP request on 19
01/09/09 11:56:20 Starting new HTTP request on 20
01/09/09 11:56:20 Starting new HTTP request on 12
01/09/09 11:56:20 12 has finished!
看起来我每秒只启动 2 个线程，这对我来说似乎很慢.我想 Console.WriteLine 可能有问题?
It still looks like I'm only getting 2 threads starting every second, which seems mighty slow to me. I suppose the Console.WriteLine could be a problem?
我设置
ThreadPool.SetMinThreads(100, 4);
和
System.Net.ServicePointManager.DefaultConnectionLimit = 100;
并得到以下结果:
01/09/09 14:00:07 Starting new HTTP request on 11
01/09/09 14:00:07 Starting new HTTP request on 81
01/09/09 14:00:07 Starting new HTTP request on 82
01/09/09 14:00:07 Starting new HTTP request on 79
01/09/09 14:00:07 Starting new HTTP request on 83
01/09/09 14:00:07 Starting new HTTP request on 84
01/09/09 14:00:07 Starting new HTTP request on 85
01/09/09 14:00:07 Starting new HTTP request on 87
01/09/09 14:00:07 Starting new HTTP request on 88
...
01/09/09 14:00:07 84 has finished! Took 323.0323 milliseconds
01/09/09 14:00:08 88 has finished! Took 808.0808 milliseconds
01/09/09 14:00:08 96 has finished! Took 806.0806 milliseconds
01/09/09 14:00:08 94 has finished! Took 806.0806 milliseconds
01/09/09 14:00:08 98 has finished! Took 801.0801 milliseconds
01/09/09 14:00:08 80 has finished! Took 799.0799 milliseconds
01/09/09 14:00:08 86 has finished! Took 799.0799 milliseconds
01/09/09 14:00:08 92 has finished! Took 799.0799 milliseconds
01/09/09 14:00:08 100 has finished! Took 812.0812 milliseconds
01/09/09 14:00:08 82 has finished! Took 1010.101 milliseconds
so 能够同时推出大量网络请求.似乎在排队(调用 STA COM+ 服务器)，这正是我所期望的.
so was able to push out a whole lot of web requests concurrently. Which seemed to queue (calling out to an STA COM+ server) so that's what I expected.
感谢您的帮助
推荐答案
您的所有(或大部分)请求是否都会发送到同一个主机?每个主机都有一个内置限制.您可以在 system.Net connectionManagement 元素的 app.config 中更改此设置.
Are all (or most) of your requests going to the same host by any chance? There's a built-in limit on a per-host basis. You can change this in app.config in the system.Net connectionManagement element.
另一件事是线程池只会逐渐增加其线程数 - 它每半秒启动一个新线程，IIRC.那会是你看到的吗?尝试从等式中删除 HttpWebRequest - 只需睡几秒钟......
The other thing is that the thread pool only ramps up its number of threads gradually - it starts a new thread every half second, IIRC. Could that be what you're seeing? Try getting rid of HttpWebRequest from the equation - just sleep for a couple of seconds instead...
我怀疑后一个问题是您最初遇到的问题，但第一个问题也会给您带来问题.
I suspect the latter problem is the one you're initially running into, but the first one is going to cause you problems as well.
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