Hardware

Thread Director doesn't do any directing, it's a a set of new registers the OS scheduler is supposed to read for feedback on how well a thread is running on a core. If APO can do it right, it means the scheduler is wrong.

15.6 HARDWARE FEEDBACK INTERFACE AND INTEL® THREAD DIRECTOR

Intel processors that enumerate CPUID.06H.0H:EAX.HW_FEEDBACK[bit 19] as 1 support Hardware Feedback Interface (HFI). Hardware provides guidance to the Operating System (OS) scheduler to perform optimal workload scheduling through a hardware feedback interface structure in memory.