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The QoS feature set already has a mechanism to associate > execution on each logical processor with an RMID or COS. PLZA allows the > system to override this per-thread association for a thread that is > executing with CPL=0. Adding Drew, and prodding Dave & James, for this discussion. At LPC it was stated that both ARM and RISC-V already have support to run kernel code with different quality of service parameters from user code. I'm thinking that Babu's implementation for resctrl may be over engineered. Specifically the part that allows users to put some tasks into the PLZA group, while leaving others in a mode where kernel code runs with same QoS parameters as user code. That comes at a cost of complexity, and performance in the context switch code. But maybe I'm missing some practical case where users want that behaviour. -Tony