Posts on X Antoine van der Lee Feb 24, 2026

Pro Tip: Use Xcode Instruments Time Profiler with AI for Performance Analysis

Article Summary

Antoine van der Lee (@twannl) found a quick way to get performance fixes from Xcode Instruments: deep copy the Time Profiler call tree and paste it into an AI agent.

He prompts the AI as a Staff iOS Engineer and points it at the raw call tree data. Testing this on his RocketSim app, the AI spotted a 21.9% CPU hit from CGContextClipToMask during video exports.

Key Takeaways

Critical Insight

Pasting Instruments call tree data into an AI agent gets you optimization suggestions in seconds instead of hours of manual inspection.

Several developers in the replies are already testing this on their own apps, and one calls it the only way they crack deep iOS production bugs.

About This Article

Problem

iOS developers spend hours manually inspecting Xcode Instruments call trees to find performance bottlenecks. They lack systematic guidance on which optimizations to prioritize.

Solution

Antoine van der Lee found a faster way. Copy the Time Profiler call tree, paste it into an AI agent, and use a Staff iOS Engineer prompt. The AI handles the performance analysis automatically.

Impact

This approach cut analysis time from hours down to seconds. Developers could quickly spot specific optimization targets like alpha-channel masking and resampling strategies.