[steveklabnik]

It depends on what you're doing. See https://github.com/jonhoo/volley, which uses blocking IO and 1:1 threads, and we're still damn fast.

There are also libraries like mio that can give you no blocking IO. Rust's standard library is deliberately minimal, exploring the ecosystem a bit is helpful, though admittedly not as easy as it could be. Working on it!

[pron]

Right. People should realize that there is no latency difference between blocking and non-blocking IO -- in fact there is a small difference in blocking IO's favor. The difference is in throughput when there is a very large number of concurrent requests, namely more than about 10K and certainly more than 2K. If you're serving under 2K concurrent requests, blocking IO is probably a better choice than nonblocking. Of course, the number of concurrent requests you need to serve depends on the time you spend serving each request; Little's Law and all that.