Not having ever used one of these E/P mixed cores CPUs I am curious to know if they are painless to use (especially under Linux). Does it ever happen that processes that should run on E cores run on P cores or viceversa? Do you have to somehow specify affinity in executables or there's some black magic that figures out automatically?

Any insights in this regard would be greatly appreciated as I am in need to change my desktop and I'm really curious regarding these 13xxx CPUs.