Gustafson's Law

Description

In computer architecture, Gustafson’s law (or Gustafson–Barsis’s law) gives the theoretical speedup in latency of the execution of a task at fixed execution time that can be expected of a system whose resources are improved. It is named after computer scientist John L. Gustafson and his colleague Edwin H. Barsis, and was presented in the article Reevaluating Amdahl’s Law in 1988.

Gustafson estimated the speedup S gained by using N processors (instead of just one) for a task with a serial fraction s (which does not benefit from parallelism) as shown here.

Related formulas

Variables

Sspeedup gained by using N processors (dimensionless)
Nnumber of processors used (dimensionless)
sserial fraction s (which does not benefit from parallelism) (dimensionless)