...considering that "cooperative multi-threading" is basically extinct and hardly applicable to high-performance servers
Thought I'd jump here and point out that, while I can't speak for the world of servers, cooperative multithreading is alive and well in the world of simulation. Here, it is really important that the results are determinitic -- the same stimuli should always give the same path through the code. I have become very frustrated over the years as support for cooperative multithreading libraries has slowly dwindled away. I have hopes that good continuation support in parrot (and P6) may stem the trend.
Opinions my own; statements of fact may be in error.