The Arm processor architecture has pushed the boundaries in a number of ways, some of which have required significant kernel changes in response. For example, the big.LITTLE architecture placed fast (but power-hungry) and slower (but more power-efficient) CPUs in the same system-on-chip (SoC); significant scheduler changes were needed for Linux to be able to properly distribute tasks on such systems. For all their quirkiness, big.LITTLE systems still feature CPUs that are in some sense identical: they can all run any task in the system. What is the scheduler to do, though, if confronted with a system where that is no longer true?