Preventing Performance Regressions on iOS Apps

JioHotstar was stuck in a frustrating cycle: fix performance issues, ship the update, watch them resurface weeks later. Sound familiar?

Saurabh Kapoor from JioHotstar shares how his team broke the performance regression cycle. They moved from reactive firefighting to proactive detection, testing performance changes before they reach millions of users.

Key Takeaways

• First attempt with Instruments and xctrace failed: 20 seconds generated 200MB files
• XCTMetric framework tracks CPU, memory, hitches, and network without custom tooling
• Performance tests only work on physical devices, not simulators
• Built custom parser using xcresulttool to extract metrics and create baselines
• enablePerformanceTestsDiagnostics flag generates memgraphs and ktrace files automatically

The article reveals why their first automation approach with Instruments created more problems than it solved, and the surprising device requirement that blocked their initial tests.