On Jan 3, 2018, at 6:26 AM, Clem Cole <clemc at ccc.com> wrote:
> 
> ​Yup microkernels are a tad slower and have more overhead, and might (probably will) cost a little more.   But I really do think simplicity beats complexity and I'll pay a bit in over head to keep it simple.

This slowdown (which is not much -- L4 shows it is about 5% or so)
is more due to h/w security architecture that has not evolved for
decades. None of the microkernel research has had any influence on
x86/ARM etc. Look at how Mill solves the problem. A protection
domain switch (a portal call) takes two extra fetches. Second, I
think the protection ring idea was counterproductive. It allowed
people to be lazy and stuff all sorts of things in the kernel.