[fauigerzigerk]

To be honest, I don't really have a good intuition or hard data on where the context switching overhead (or other limits) starts to bite, because I have always avoided architectures that go into the hundereds or thousands of threads.

Maybe you are right and it's one of those urban myths that we sometimes carry over from times long past based on assumptions that are no longer true.

I would love to have more hard information on that one, because I think that the currently fashionable async/event based way of doing a lot of things makes programs much harder to understand and write.

[dboreham]

Good rule of thumb for modern kernel and server class hardware : 100's of (native) threads is ok. 1000's will probably be ok. 10's of 1000 is where you will start to see trouble and 100's of 1000 will most likely cause you to pull out your hair. So the comment above about 175 threads being too many is incorrect.