Implementing the Load Slice Core on a RISC-V based microarchitecture

Abstract: As cores have become better at exposing Instruction-Level Parallelism (ILP), they have become bigger, more complex, and consumes more power. These cores are approaching the Power- and Memory-wall quickly. A new microarchitecture proposed by Carlson et. al claims to solve these problems. They claim that the new microarchitecture, the Load Slice Core, is able to outperform both In-Order and Out-of-Order designs in an area and power restricted environment. Based on Carlson et. al.’s work, we have implemented and evaluated a prototype version of their Load Slice Core using the In-Order Core Ariane. We evaluated the Load Slice Core by comparing the LSC to an IOC when running a microbenchmark designed by us, and when running a set of Application Benchmarks. The results from the Microbenchmark are promising, the LSC outperformed the comparable IOC in each test but problems related to the configuration of the design were found. The results from the Application Benchmarks are inconclusive. Due to time constraints, only a partially functioning LSC were compared to a comparable IOC. From these results we found that the LSC performed comparably or slightly worse than its IOC counterpart. More research on the subject is required for any conclusive statement on the microarchitecture can be made, but it is the opinion of this paper’s authors that it does show promise.