Latency Principles

This skill provides a systematic approach to understanding and reducing latency in software systems, based on the book "Latency" by Pekka Enberg.

Core Concepts

Latency is the time delay between a cause and its observed effect. It is a distribution, not a single number.

Quick Reference

• Little's Law: Concurrency = Throughput * Latency. Use to size queues and thread pools.
• Amdahl's Law: Speedup is limited by the serial part of the task. Use to estimate max benefit of parallelization.
• Tail Latency: The experience of the 99th percentile users. In high-fanout systems, tail latency dominates.

For detailed definitions and laws, see references/principles.md.

Diagnosis & Optimization

When facing latency issues, follow this systematic approach: