This writeup talks like MMU&#x27;s always kill performance. It ignores over a decade of work by microkernels to reduce that problem to single-digit percentages. L4 even fits in a L1 cache with plenty room to spare. QNX also has clever low-oveehead scheduler &amp; message passing. LynxSecure leaves CPU 97% or so idle at 100,000 context switches a second.<p>And all this even assumes you have to do the switch. That&#x27;s not necessary if you split your system between kernel and user threads that run side by side on different cores with message passing, memory, or CPU interrupts to do notification.<p>So, not only are VM&#x27;s and Unikernels old, their advocates are ignoring improvements to the other side of CompSci for MMU systems. Interestingly, that was the side making self-healing, live-updating, and NSA-resisting systems all these years on COTS hardware. A little weird that such architectures get the least attention. ;)