The .NET Framework BCL contains a very nice implementation of a thread pool (the
But, this class is not suitable for the following scenarios:
- Long-running operations. Usually, for long-running operations, it is recommended to use the
ThreadPool is per process. It means that a situation when there is no available thread in the
ThreadPool can happen pretty often. What if you have a very important and emergent work item and do not want to take such a risk? But pretty often, especially when you have an application with a number of app domains (like IIS or SQL server), you can run out of threads in the thread pool...
ThreadPool does not support
BeginInvoke methods of all delegates internally pass control to
ThreadPool itself does not support
Generally, there are number of strict recommendations about when you should use
ThreadPool and when you should use the
Thread class directly or
MulticastDelegate.BeginInvoke. The main problem of
System.Threading.ThreadPool is that it is per process. So, if you have a set of very important tasks to do, and also have a set of third-party assemblies that you host in the application, there is always a probability that your important tasks will be delayed. In the case of the
CustomThreadPool, you have a separate threadpool for each application domain.
You can have as many
CustomThreadPools as application domains.
This is just the initial version of
CustomThreadPool, and I plan to extend it in future. Maybe, instead of
WaitHandles, I will use
Monitor.Pulse to achieve better flexibility (and probably performance).
Using the Code
CustomThreadPool has three methods:
A sample of how to use these methods is provided below:
public static class Program
public static void Main()
private static void DoSomething()
private static int MyLongRunningFunc()
private static void MyLongRunningFuncFinished(IAsyncResult result)
Points of Interest
I've learned a lot about multithreading, especially about volatile fields and
- 20 Nov, 2008 -- Initial Posting
- 10 Mar, 2009 -- Added dispose functionality to
CustomThreadPool. Class changed from static to "instanceable" to support creation of multiple instances within the same App Domain.