Alex Rivera | Logout

Thread.Sleep for less than 1 millisecond

Asked 2011-06-06T15:57:20.960
41

I want to call thread sleep with less than 1 millisecond. I read that neither thread.Sleep nor Windows-OS support that.

What's the solution for that?

For all those who wonder why I need this: I'm doing a stress test, and want to know how many messages my module can handle per second. So my code is:

 // Set the relative part of Second hat will be allocated for each message 
 //For example: 5 messages - every message will get 200 miliseconds 
 var quantum = 1000 / numOfMessages;

 for (var i = 0; i < numOfMessages; i++)
 {
      _bus.Publish(new MyMessage());
      if (rate != 0) 
          Thread.Sleep(quantum);
 }

I'll be glad to get your opinion on that.

c# .net multithreading
Edit
Report

2 Answers

53

You can't do this. A single sleep call will typically block for far longer than a millisecond (it's OS and system dependent, but in my experience, Thread.Sleep(1) tends to block for somewhere between 12-15ms).

Windows, in general, is not designed as a real-time operating system. This type of control is typically impossible to achieve on normal (desktop/server) versions of Windows.

The closest you can get is typically to spin and eat CPU cycles until you've achieved the wait time you want (measured with a high performance counter). This, however, is pretty awful - you'll eat up an entire CPU, and even then, you'll likely get preempted by the OS at times and effectively "sleep" for longer than 1ms...

answered 2011-06-06T16:00:15.590
9

Most of the legitimate reasons for using Thread.Sleep(1) or Thread.Sleep(0) involve fairly advanced thread synchronization techniques. Like Reed said, you will not get the desired resolution using conventional techniques. I do not know for sure what it is you are trying to accomplish, but I think I can assume that you want to cause an action to occur at 1 millisecond intervals. If that is the case then take a look at multimedia timers. They can provide resolution down to 1ms. Unfortunately, there is no API built into the .NET Framework (that I am aware of) that taps into this Windows feature. But you can use the interop layer to call directly into the Win32 APIs. There are even examples of doing this in C# out there.

answered 2011-06-06T18:10:02.430

Your Answer