This document discusses optimizing performance in Eclipse-based tools. It recommends measuring performance using tools like VisualVM and YourKit to identify issues. Common problems include expensive calls in loops and slow builders. Solutions include caching results, reducing garbage collection, and optimizing for common cases. When implementing visitors or type checking, it is important to avoid iterating over collections and make the code simple and fast. Reading bytecode directly is faster than using Eclipse APIs. Reconciling and content assist need to be optimized as they must be fast. Caching and reducing startup workload can improve startup time. The overall approach is to measure, optimize, and repeat.