Law

Gustafson's Law

If your problem grows when you add more processors, you can get more speed than Amdahl suggests.

How to use it. Ask whether the work is fixed or whether it grows with capacity. Fixed work hits Amdahl's limit. Growing work hits Gustafson's, which is more generous.

How it gets misused. Used to wave Amdahl away. Both apply, to different kinds of work.

Law Amdahl's Law Adding more processors only helps with the parts of the work that can run in parallel.

Gustafson's Law

Related