In resource-constrained IoT devices, traditional application runtimes often struggle with limited performance and inflexible update mechanisms. WebAssembly (Wasm) has emerged as a promising technology to overcome these bottlenecks. However, existing Wasm implementations are not yet fully optimized for practical IoT environments, particularly in terms of JavaScript performance and modular over-the-air (OTA) updates on production IoT systems. To fill the gap, we propose Li-WaC, a lightweight, high-performance, and efficiently updatable WebAssembly Container framework for IoT operating systems.Specifically, we integrate a Wasm runtime into the event-driven Context Hub Runtime Environment (CHRE) framework. By treating the Wasm runtime as a standalone dispatch entity, Li-WaC runs Wasm modules as standard nanoapps, similar to native C/C++ applications. Performance-intensive tasks that were previously handled in JavaScript can then be offloaded to Wasm. We implemented and deployed Li-WaC within Vela, a production IoT operating system developed and maintained by Xiaomi, a leading global manufacturer of smartphones and IoT devices. On compute-oriented microbenchmarks, the AOT mode of Li-WaC achieves a 13× average speedup over QuickJS, approaching V8 on these microbenchmarks. In a production deployment study, we also observed smaller update packages, shorter installation times, and higher upgrade adoption rates under modular updates, where the upgrade adoption rate is the share of devices in the target cohort that completed an upgrade within a stated observation window.

@inproceedings{paperbot12614,
  title = {Li-WaC: A Lightweight WebAssembly Container for Independently Upgradable IoT Applications in Xiaomi Vela},
  author = {Bin Liao and Canfeng Zheng and Shiwen Shan and Qi Huang and Junjie Dong and Xiang Xiao and Yaoyao Gu and Yuxin Su},
  booktitle = {ASE},
  year = {2026},
  doi = {10.1145/3832783.3834502}
}