Gustafson's Law - alternative version

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, in its alternative formulation.

Related formulas

Variables

Slatencytheoretical speedup in latency of the execution of the whole task (dimensionless)
pspeedup in latency of the execution of the part of the task that benefits from the improvement of the resources of the system (dimensionless)
spercentage of the execution workload of the whole task concerning the part that benefits from the improvement of the resources of the system before the improvement (dimensionless)