> This information is exposed specifically so that app developers can optimize for the cache line size in use. I very much doubt Apple would report a false numb

> This information is exposed specifically so that app developers can optimize for the cache line size in use. I very much doubt Apple would report a false number. No, this number is used for compatibility reasons. OS is free to pull shenanigan behind apps to take care of CPU cache line size changing underneath them (like using a larger size so it'll align on everything; 128b aligned is 64b aligned too).