Past Event: Babuška Forum

The benefits of breaking through standard interfaces

Robert van de Geijn, Professor, UT Austin

Abstract

Over the past decade, the BLAS-like Library Instantiation Software (BLIS) project has carefully revisited past progress on how to structure the implementation of the level-3 BLAS-like operations (matrix-matrix computations) in particular and all basic linear algebra operations in general. This has resulted in a refactoring of prior approaches that yields a more flexible, more easily maintained, highly portable, yet high-performing and scalable software library. BLIS now casts Goto's algorithm in terms of five portable loops (written in C99) around a “microkernel" that updates a small submatrix of C that fits in registers. It is only this microkernel that needs to be customized for a new architecture when implementing matrix multiplication. The refactoring exposed in BLIS drastically reduced the size, complexity, and number of assembly kernels necessary for supporting high-performance across all datatypes and level-3 operations. We will discuss how the science that underlies the high-performance implementation of GEMM, BLIS has opened up the field to new directions of research and to new contributors. This work is in collaboration with current and former members of the Science of High-Performance Computing group and many external collaborators. It is/was supported by multiple grants from the National Science Foundation (including Awards ACI-1148125 and ACI-1550493) and gifts from AMD, Facebook, HP, Huawei, Intel, Microsoft, Oracle, Qualcomm, and Texas Instruments. Bio Robert van de Geijn is professor of computer science and member of the Institute for Computational Engineering and Sciences. He received his Ph.D. in Applied Mathematics from the University of Maryland, College Park. His interests are in linear algebra, high-performance computing, parallel computing, and formal derivation of algorithms. He heads the FLAME project, a collaboration between UT Austin, Universidad Jaume I (Spain), and RWTH Aachen University (Germany). This project pursues foundational research in the field of linear algebra libraries and has led to the development of the libflame library, a modern, high-performance dense linear algebra library that targets both sequential and parallel architectures. One of the benefits of this library lies with its impact on the teaching of numerical linear algebra, for which van de Geijn received the UT President’s Associates Teaching Excellence Award. He has published several books and more than 100 refereed publications.