Performance Review

Identify where code is actually slow, why it's slow, and what the minimum intervention is to fix it. Performance problems are almost always in one place — find that place before touching anything else.

"Premature optimization is the root of all evil." — Donald Knuth "But profile first." — Everyone who has debugged production

Skill workflow — performance review often follows architecture review: performance-review (find the cost) → triage-bug (root-cause a specific regression) → refactoring (fix it)

Philosophy

Most performance problems are not where you think they are. The cardinal sin is optimizing without measuring. The second sin is over-engineering a system to handle load it will never see.