): The algorithm that calculates what change to apply based on the error. Control Input (
The controller is the most common algorithm used to close the feedback loop. Feedback Control for Computer Systems [Book] - O'Reilly Feedback Control for Computer Systems
): The target value (e.g., a 95% cache hit rate or 200ms latency). Controller ( ): The algorithm that calculates what change to
Feedback control for computer systems applies classical control theory—originally used for physical systems like engines—to digital environments like web servers, databases, and caches. It enables systems to self-adjust to maintain performance goals despite unpredictable workloads or resource shifts. ⚙️ Core Concepts of Feedback Control Controller ( Feedback control for computer systems applies
The primary objective of a feedback loop is to minimize the —the difference between a desired state ( Setpoint ) and the actual state ( Measured Output ). Setpoint (