multithreading using threadPool or new thread() in server app

Question

I have done a bunch of reading on the dynamics and implications of multi-threading in a server app (starving the clr thread pool, etc.) but let's say for sake of argument I have EXACTLY 4 async processes I need to accomplish per request of my (asp.net) page... Now let's say time is the more critical element and my site should not experience heavy traffic. In this scenario, is it preferable to spawn 4 threads using the new Thread() approach or the ThreadPool.QueueUserWorkItem method?

My concern (and my point) here is that using the ThreadPool method, it may create a thread pool that is too large than what I really want? When I only need 4 threads, can't I just spawn them myself to keep the number of allocated app domain, clr threads minimal?

Answer 1

Spawning a thread is a very costly and therefore high-latency operation. If you want to manage threads yourself, which would be reasonable but not required, you have to build a custom pool.

Using thread pool work items is not without danger because it does not guarantee you a concurrency level of 4. If you happen to get 2 or 3 you will have much more latency in your HTTP request.

I'd use the thread-pool and use SetMinThreads to ensure that threads are started without delay and that there are always enough.