@siracusa Fun fact: “performance” and “efficiency” are stringly typed in both the kernel and I/O Registry:

$ sysctl -a | grep "hw.perflevel"

$ ioreg -l -b -p "IODeviceTree" -r -n "cpus"

("cluster-type" will be either “P" or “E”)

I can't imagine how they are going to change the meaning of “performance" without breaking a bunch of other low-level things.