Thread.Sleep(0) : What is the normal behavior?

Question

To my understanding a Thread.Sleep(0) force a context switch on the OS.

I wanted to check what was the maximum amount of time that could pass in an application befor

Answer 1

My understanding is that Thread.Sleep(0) does not force a thread context switch, it simply signals the task scheduler that you are willing to give up the rest of your time slice if there are other threads waiting to execute.

Your loop around Sleep(0) is chewing up CPU time, and that will have a negative effect on other applications (and laptop battery life!). Sleep(0) doesn't mean "let everything else execute first", so your loop will be competing for execution time with other processes.

Passing a non-zero wait time to Sleep() would be marginally better for other apps because it would actually force this thread to be put aside for a minimum amount of time. But this is still not how you implement a minimum-impact background thread.

The best way to run a CPU bound background thread with minimum impact to foreground applications is to lower your thread priority to something below normal. This will tell the scheduler to execute all normal priority threads first, and if/when there is any other time available then execute your low priority thread. The side effect of this is that sometimes your low priority thread may not get any execution time at all for relatively long periods of time (seconds) depending on how saturated the CPU is.