iOS UI Rendering Performance

UI rendering performance of an iOS app is measured by observing if app interactions in key user journeys are natural and instant.

Following metrics are used to measure UI rendering app performance of an iOS app :

• % of Slow Frames rendered : % of frames taking more than 16ms to render

How does it impact user experience

Delay in user interaction, hangs, or hitches can cause user experience issues by making the app feel unresponsive and frustrating for users. These issues can lead to poor user engagement and negatively impact user retention, app reviews, and overall app success.

Threshold Guidelines

Recommended thresholds are :

• % slow frames in a session <= 25% of overall frames rendered

How to improve UI Rendering Performance

Following are the recommendations to improve UI Rendering Performance :

• Simplify the app’s view hierarchy and reduce the number of subviews to minimize the rendering workload.
• Optimize images and graphics to reduce their memory footprint and improve rendering speed.
• Use auto-layout constraints and avoid hard-coding frames to improve performance and ensure layout correctness.
• Use Core Animation efficiently and avoid performing heavy animation tasks on the main thread.