): The algorithm that calculates what change to apply based on the error. Control Input (
): The lever the controller pulls (e.g., scaling server instances or adjusting cache size). The computer process being managed. Measured Output ( ): The actual current performance metric. 🛠️ The PID Controller: The Standard Algorithm 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 Feedback Control for Computer Systems