33,000 lines of XML to tell you heavyWork() is slow: how I tamed xctrace for LLMs
Last week I was profiling a Swift app with Instruments. Standard procedure: xctrace record, xctrace export, copy the XML to Claude Code’s context, ask it to find the hotspots. Claude responds: “The XML is too large, I can’t process it reliably.” 33,553 lines of XML. For a program with two functions. The real problem xctrace export is a fantastic tool. It gives you everything: every sample, every backtrace, every frame with its binary, memory address, and UUID. It’s exhaustive, precise, and complete. ...