FT-BLAS: A Fault Tolerant High Performance BLAS Implementation on x86 CPUs

Basic Linear Algebra Subprograms (BLAS) serve as a foundational library for scientific computing and machine learning. In this article, we present a new BLAS implementation, FT-BLAS, that provides performance comparable to or faster than state-of -the-art BLAS libraries, while being capable of tolerating soft errors on-the-fly. At the algorithmic level, we propose a hybrid strategy to incorporate fault-tolerant functionality. For memory-bound Level-1 and Level-2 BLAS routines, we duplicate computing instructions and re-use data at the register level to avoid memory overhead when validating the runtime correctness. Here we novelly propose to utilize mask registers on AVX512-enabled processors and SIMD registers on AVX2-enabled processors to store intermediate com-parison results. For compute-bound Level-3 BLAS routines, we fuse memory-intensive operations such as checksum encoding and verification into the GEMM assembly kernels to optimize the mem-ory footprint. We also design cache-friendly parallel algorithms for our fault-tolerant library. Through a series of architectural-aware optimizations, we manage to maintain the fault-tolerant overhead at a negligible order (<3%). Experimental results obtained on widely-used processors such as Intel Skylake, Intel Cascade Lake, and AMD Zen2 demonstrate that FT-BLAS offers high reliability and high performance - faster than Intel MKL, OpenBLAS, and BLIS by up to 3.50%, 22.14%, and 21.70%, respectively, for both serial and parallel routines spanning all three levels of BLAS we benchmarked, even under hundreds of errors injected per minute.