Most of the speed gain comes from avoiding thread switching as much as possible. I developed the idea of commandeering, where an actor which sends a message to another actor that is idle can safely process the message sent on the same thread.

Additional speedups came from message buffering and the optional use of 2-way messages for implicit flow control.

Message passing between actors runs between 80 and 200 million per second on an i7, depending on the mode of delivery.

Currently looking for early adopters as I believe this is production ready.

https://github.com/laforge49/JActor