Android Developers Backstage Episode 213: Compose runtime and performance
Mar 4, 2025
Leland Richardson and Chuck Jasky, both key members of Google's Compose team, dive into performance optimization for the Compose toolkit. They discuss groundbreaking features like Pausable Composition, which automates updates and enhances rendering speed. The duo also tackles the challenges of managing mutable versus immutable objects and the intricacies of equality in Kotlin. Additionally, they touch on the balance between stability and performance, and highlight new diagnostic tools improving the developer experience in Android app development.
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Pausable Composition Concept
- Pausable Composition lets Compose break up long composition tasks across frames automatically.
- This reduces jank by allowing heavy UI work to finish over multiple frames during prefetching.
Strong Skipping Optimization
- Compose now assumes instance equality for unstable (mutable) objects to decide recomposition skipping.
- This change improves performance and aligns better with developer expectations, enabled by default in Kotlin 2.1.
Balance Performance Focus
- Over-focusing on stability and skipping can distract from other important performance aspects.
- Balance your attention between minimizing recompositions and optimizing expensive layout or drawing operations.