Finding a "Kneedle" in a Haystack: Detecting Knee Points in System Behavior
Computer systems often reach a point at which the relative cost to increase some tunable parameter is no longer worth the corresponding performance benefit. These "Knees" typically represent beneficial points that system designers have long selected to best balance inherent trade-offs. While prior work largely uses ad hoc, system-specific approaches to detect knees, the authors present Kneedle, a general approach to online and offline knee detection that is applicable to a wide range of systems. They define a knee formally for continuous functions using the mathematical concept of curvature and compare their definition against alternatives.