The Comeback of Reed Solomon Codes

Abstract

Distributed storage systems utilize erasure codes to reduce their storage costs while efficiently handling failures. Many of these codes (e. g., Reed-Solomon (RS) codes) rely on Galois Field (GF) arithmetic, which is considered to be fast when the field characteristic is 2. Nevertheless, some developments in the field of erasure codes offer new efficient techniques that require mostly XOR operations, and are thus faster than GF operations. Recently, Intel announced [1] that its future architecture (codename “Ice Lake”) will introduce new set of instructions called Galois Field New Instruction (GF-NI). These instructions allow software flows to perform vector and matrix multiplications over GF (28) on the wide registers that are available on the AVX512 architectures. In this paper, we explain the functionality of these instructions, and demonstrate their usage for some fast computations in GF(28). We also use the Intel® Intelligent Storage Acceleration Library (ISA-L) in order to estimate potential future improvement for erasure codes that are based on RS codes. Our results predict $\approx 1.4\mathrm{x}$ speedup for vectorized multiplication, and 1.83x speedup for the actual encoding.