Performance Regression on webOS After Upgrading Flutter Version (CanvasKit/WASM Issues)

Web App Development
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Share information and tips or post questions regarding Web app development.We’re seeing major performance and rendering regressions on LG webOS devices after upgrading our Flutter version from 3.27.4 (HTML renderer) to 3.32.8 (CanvasKit). Since HTML renderer is deprecated from 3.29 onward, we moved to CanvasKit, and the issues began immediately. No other functional changes were made on the application side.

We also tested with Flutter 3.35.5 and 3.38.3 (CanvasKit/WASM).

  • 3.35.5 performs slightly better, but the core problems still persist.

  • 3.38.3 shows similar issues as 3.32.8.

These problems did not exist on Flutter 3.27.4 HTML renderer, which worked smoothly across webOS versions 5.0+ (2GB RAM devices).

Key Technical Observations

webOS 8 and above

  • Noticeable UI sluggishness and delayed frame rendering.

  • Severe focus navigation issues using the remote.

  • Major jank and frame drops during transitions.

  • Very slow initialization times.

  • RAM usage spikes during runtime and often reaches upper limits, resulting in “low memory” process kill.

  • Overlay screens not disposed reliably → stale UI frames remain visible.

webOS 5.5 and below

  • The app gets stuck on the splash screen and does not proceed.

webOS 6 & 7

  • Not tested yet due to device availability.

Questions for the LG webOS Engineering / Community

We are looking for insights from the webOS engineering team or other developers working with Flutter + CanvasKit/WASM on LG TVs:

  1. Are these performance regressions expected with current CanvasKit/WASM support on webOS?

  2. Any suggested optimizations or flags to improve Flutter’s CanvasKit/WASM performance on the TV browser stack?

  3. Is LG aware of limitations with specific Chromium builds bundled in certain webOS versions when running CanvasKit-heavy apps?

  4. From which Chromium version do performance bottlenecks typically start appearing for high-complexity CanvasKit/WASM apps?

  5. Which Chromium version is recommended for stable CanvasKit and WebAssembly rendering on TV-grade hardware?

  6. Are there known constraints (memory limits, WebGL2 availability, WASM tuning, etc.) that developers should account for?

  7. Does LG have recommended minimum TV hardware specifications (CPU, GPU, RAM, WebGL/WASM capabilities) for ensuring smooth rendering on large applications?

  8. Are any webOS firmware updates planned that might improve WASM or CanvasKit performance?

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webOS TV uses different web engines depending on the webOS version. Please check compatibility with the web engine. Thank you.