Which is why DragonflyBSD was forked during the disagreement on FreeBSD's SMPng. Matt implemented more of a message passing system instead and Sepherosa Ziehau

Which is why DragonflyBSD was forked during the disagreement on FreeBSD's SMPng. Matt implemented more of a message passing system instead and Sepherosa Ziehau made all kinds of improvements to share as little as possible between cores and thus enable higher scalability in particular for networking.