Performance and efficiency cores, unified memory, accelerators on-package. The uniform-core model that every piece of scheduling and benchmarking folklore assumes has stopped being true, and the machine that replaces it does more per watt than anything symmetric ever will.
The architecture monoculture is ending, and that sits upstream of almost everything interesting in systems work. The hard part was never the instruction set; it is fifteen years of software that has only ever been built on one.
Five Raspberry Pis, a switch and a great deal of green cable. The compute was never the point; a real network between real machines fails in ways a single-host simulation will never show you.
