In a Sneak Peek for OS X Leopard, Apple shows a debugging mode in Xcode that works something like music sequencers.
Taking its interface cues from timeline editors such as GarageBand, now you can visualize application performance like nothing you’ve seen before. Add different instruments so you can instantly see the results of code analyzers. Truly track read/write actions, UI events, and CPU load at the same time, so you can more easily determine relationships between them.