[functional_test]

I'll start by saying that I agree with almost everything you've said. I can think of one time where a loop with a sleep might be appropriate though -- if you have something, perhaps some IO channel like a log, and you want it flushed regularly, but not every time a write is performed. With a long enough sleep (>100ms) the performance overhead ought to be low. Is there a better way to design that though?

[std_throwaway]

In that case you don't want to sleep. You want to wait until a condition (new data) or a timeout (100ms) occurs.

The reasoning is that you don't know how much data will arrive in the next 100ms and if you sleep either a buffer could overrun or something else could block. Therefore you need to flush the buffer either when enough data has accumulated or if a timeout has occured.

[functional_test]

I can see where you're coming from. For my particular apication that's not a concern (and I have sequence numbers to know when I've dropped data).