Exploiting Asymmetric SIMD Register Configurations in ARM-to-x86 Dynamic Binary Translation

Abstract

Processor manufacturers have adopted SIMD for decades because of its superior performance and power efficiency. The configurations of SIMD registers (i.e., the number and width) have evolved and diverged rapidly through various ISA extensions on different architectures. However, migrating legacy or proprietary applications optimized for one guest ISA to another host ISA that has fewer but longer SIMD registers through binary translation raises the issues of asymmetric SIMD register configurations. To date, these issues have been overlooked. As a result, only a small fraction of the potential performance gain is realized due to underutilization of the host's SIMD parallelism and register capacity.In this paper, we present a novel dynamic binary translation technique called spill-aware SLP (saSLP), which combines short ARMv8 NEON instructions and registers in the guest binary loops to fully utilize the x86 AVX host's parallelism as well as minimize register spilling. Our experiment results show that saSLP improves the performance by 1.6X (2.3X) across a number of benchmarks, and reduces spilling by 97% (99%) for ARMv8 NEON to x86 AVX2 (AVX-512) translation.