Question

I have a simple collection which I’m looping through like this:

foreach (MyObject mo in myObjects)
{
   myObject.RunAcync();
}

RunAsync executes code in a separate thread, using new Thread(()=>{ .. }).Start(), it’s not in my power to change the code of RunAsync. I need to limit the number of instances of myObject running concurrently to N (real numbers are 2..10). What is the efficient way to do that using .NET4 and c#?

Answer 1

If you can modify RunAsync, with what we have now (.NET 4) and what’s imminent (now when you think about it, .NET 4.5), I would use the Task Parallel Library (TPL) and return some sort of Task object from RunAsync. You can then easily tell what is done and what is running, and use the built-in TPL load balancing to limit the number of running tasks. Alternatively, if you had a non-async version of the method, you could also use the TPL’s Parallel.ForEach to invoke the method and it would deal with load-balancing and run only enough of the methods at one time to avoid performance issues