Superoptimization Of Memory Subsystems

The disparity in performance between processors and main memories has led computer architects to incorporate large cache hierarchies in modern computers. Because these cache hierarchies are designed to be general-purpose, they may not provide the best possible performance for a given application. In this paper, we determine a memory subsystem well suited for a given application and main memory by discovering a memory subsystem comprised of caches, scratchpads, and other components that are combined to provide better performance. We draw motivation from the super-optimization of instruction sequences, which successfully finds unusually clever instruction sequences for programs. Targeting both ASIC and FPGA devices, we show that it is possible to discover unusual memory subsystems that provide performance improvements over a typical memory subsystem.