John Gustafson (scientist)

John Gustafson is an American scientist and engineer notable for his work in high-performance computing, computer architecture, and applied mathematics. He is best known for formulating Gustafson's Law (also known as Gustafson-Barsis's Law), which provides a counterpoint to Amdahl's Law regarding the theoretical speedup achievable through parallel processing.

Gustafson earned his Ph.D. in Applied Mathematics from Iowa State University. He has held research and leadership positions at various institutions, including the Ames Laboratory, Sandia National Laboratories, and QCI (formerly Quantum Computing, Inc.). His career has focused on exploring and developing innovative approaches to computing, with a particular emphasis on scaling algorithms for parallel architectures.

Gustafson's Law proposes that problems can be scaled up to take advantage of increased computing resources, implying that the amount of work performed can increase with the number of processors, rather than being limited by the serial portion of the code as suggested by Amdahl's Law. This perspective helped shift the focus in parallel computing research from minimizing serial overhead to maximizing the problem size that can be effectively solved.

In addition to his work on Gustafson's Law, Gustafson has contributed to advancements in unum arithmetic (a form of universal number arithmetic), posit arithmetic (a simplified variant of unum), and the development of novel computer architectures. He continues to be involved in research and development related to advanced computing technologies.