FlexPointer: Fast Address Translation Based on Range TLB and Tagged Pointers

Page-based virtual memory suffers from costly page walks because of the gap between application workload sizes and TLB capacity. In this paper, we propose a tagged-pointer-based system, FlexPointer, to solve this problem. FlexPointer creates memory ranges from objects larger than a certain threshold by allocating contiguous physical pages for them. Virtual addresses within a range share a common translation entry, thus greatly expanding the TLB capacity. Because such objects are rare, we can assign each of them a unique ID and pass it to the hardware in pointer tags. According to our trace-based simulation results, FlexPointer can reduce nearly all the L1 TLB misses and page walks for a variety of memory-intensive workloads, providing a 14% performance improvement on average.