language agnostic - Is Sleep() evil?

Question

First of all, there are many cases where Sleep() is misused, for example to "synchronize" threads or to regularily poll a value where a notification function would do (In Win32 WaitForSingleObject for example)

But what about other use cases? Is Sleep always evil? If no, what are good use cases for Sleep? If yes, why do almost all languages have some kind of Sleep statement?

PS: I've asked this question because of one of the comments of another question. There the OP states, that in his opinion, Sleep is to be avoided like goto.

Answer 1

I actually believe the assertion you linked is correct. The problem is sleep is being used (as you noted) as an inefficient substitute for notification mechanisms. Sleep is always inferior to a properly implemented notification mechanism, If you are waiting for an event. If you actually need to wait a specific amount of time for something, then sleep is appropriate.

For example, in some network protocols, you make use of a technique known as exponential backoff, where if you detect a collision on the network, you want to wait a random (and exponentially increasing) amount of time before you retry. In this case sleep is appropriate because you're not trying to wait for an event to happen, you're trying to wait for a specific amount of time to pass.