Thread Pool vs Thread Spawning

Question

Can someone list some comparison points between Thread Spawning vs Thread Pooling, which one is better? Please consider the .NET framework as a reference implementation that supports both.

Answer 1

Thread pool threads are much cheaper than a regular Thread, they pool the system resources required for threads. But they have a number of limitations that may make them unfit:

• You cannot abort a threadpool thread
• There is no easy way to detect that a threadpool completed, no Thread.Join()
• There is no easy way to marshal exceptions from a threadpool thread
• You cannot display any kind of UI on a threadpool thread beyond a message box
• A threadpool thread should not run longer than a few seconds
• A threadpool thread should not block for a long time

The latter two constraints are a side-effect of the threadpool scheduler, it tries to limit the number of active threads to the number of cores your CPU has available. This can cause long delays if you schedule many long running threads that block often.

Many other threadpool implementations have similar constraints, give or take.