Background -TLB = Cache for virtual to physical address translations -TLB miss -> high cost time consumption -TLB does not support coherence(일관성) -> Need OS support (= TLB Shootdown) -Maintain Coherency Using IPI (Inter Processor Interrupt) -ACK from Remote Core takes a lot of Cycles(>=1000) -Furthermore, longer due to PTI to avoid the Meltdown vulnerability (PTI = Page Table Isolation, Separate..