Universal Scalability Law

External

• Neil J. Gunther, “A Simple Capacity Model of Massively Parallel Transaction Systems,” proceedings of CMG National Conference (1993) http://www.perfdynamics.com/Papers/njgCMG93.pdf
• Baron Schwartz, "Practical Scalability Analysis with the Universal Scalability Law" https://www.vividcortex.com/resources/universal-scalability-law/

Internal

• Software Architecture
• Reactive Programming
• Amdahl's Law

Overview

Pushing utilization beyond a certain point will yield diminishing or even negative returns. This observation was formalized by Neil J. Guther as Universal Scalability Law (USL).

USL introduces the cost of communication - coherency, or the cost of keeping data in sync - as a variable in the equation.