Can the thread per request model be faster than non-blocking I/O?

Question

I remember 2 or 3 years ago reading a couple articles where people claimed that modern threading libraries were getting so good that thread-per-request servers would not only be

Answer 1

Like that presentation said - there's speed and there's scalability.

One scenario where thread-per-request will almost certainly be faster than any async solution is when you have a relatively small number of clients (e.g. <100), but each client is very high volume. e.g. a realtime app where no more than 100 clients are sending/generating 500 messages a second each. Thread-per-request model will certainly be more efficient than any async event loop solution. Async scales better when there are many requests/clients because it doesn't waste cycles waiting on many client connections, but when you have few high volume clients with little waiting, it's less efficient.

From what I seen, authors of Node and Netty both recognize that these frameworks are meant to primarily address high volumes/many connections scalability situations, rather than being faster for for a smaller number of high volume clients.