Changing thread priority to make my program and computer more responsive

Question

I've written a .NET winforms application that uses a secondary thread to do some heavy processing, which communicates it's progress back to the UI thread. Everything works correctly, the form shows the progress, and I've also created a cancel button to interrupt the processing thread. However, when the time consuming process is going the application and my entire computer slows way down. It takes a long time drag windows around, and there is even a significant delay when trying to type letters into notepad.

I'm assuming I need to reduce the priority of the processing thread, and/or increase the priority of the UI thread. Is this right? Right now both threads are Normal priority.

Is it just as easy as the follwing? Or is there something else I should do?

Thread.CurrentThread.Priority = ThreadPriority.AboveNormal;

How should I change the priorities? Should I reduce the priority of the processing, or increase the priority of the UI, or both? And to what setting? AboveNormal, or highest?

Answer 1

I dont necessarily think thread priority is your issue (though it could be part of it). Take a look at this SO question: Background Worker Thread Priority.

It is probably overly tight loops in your background thread which are keeping cpu time on that thread. There are several ways to fix it from the brutal (thread sleeps) to the more reasonable (mutexs and events).

You can also try profiling the background thread (either directly, or in a test harness) to see where it is spending the majority of its time, and try to isolate this with async events or similar offloading techniques.