Exploring Heterogeneous-ISA Core Architectures for High-Performance and Energy-Efficient Mobile SoCs
Wooseok Lee, Dam Sunwoo, Christopher D. Emmons, Andreas Gerstlauer, Lizy K. John · 2017
In this paper, we explore opportunities to increase energy efficiency by providing cores with restricted functionality, but without necessarily impacting performance. We aim to achieve this by removing support for complex but less frequently executed instructions since instruction mixes used by real-world workloads are often heavily biased. We investigate which instructions are worthwhile to remove by analyzing a subset of instructions in the ARM ISA and their corresponding logic burden in the microarchitecture. We propose a heterogeneous-ISA system to achieve energy efficiency without performance degradation using a system architecture that combines both full- and reduced-ISA cores. Results show that by providing the flexibility of heterogeneous-ISA cores, the proposed system can improve energy efficiency by 12% on average and up to 15% for applications that do not require NEON support, all without performance overhead.