[corty]

Context switching overhead is bad for microkernel performance. All the reasons why the userspace wireguard implementation was slower apply to each and every part of a microkernel system. And all of this got worse with spectre and meltdown, secure context switches are now even more expensive. Modern CPUs generally always increase the context switching cost, they optimize for single-process benchmarks.

So microkernels are dead, performance buries them deeper and deeper.