Seamless Offloading of Web App Computations From Mobile Device to Edge Clouds via HTML5 Web Worker Migration

Abstract

Future mobile applications, such as mobile cloud gaming or augmented reality, require not only high computation power but strict latency constraints. To provide computing resources with ultra-low latency, a new form of cloud infrastructure called edge cloud has been proposed, which distributes computing servers at the edges of the network. A primary concern of edge cloud is that a physical server running a service can change as the client moves, so the service has to be quickly migrated between servers for seamless computation offloading. This paper tackles the issue in the context of web applications, whose computation-intensive codes are written in JavaScript and webassembly. The basic building block of our system is a mobile web worker, which extends HTML5 web worker to support migration across the client, edge, and cloud servers. Our system migrates a mobile web worker from mobile device to an edge server to minimize execution latency. The immigrated worker can move again to other servers for better performance or service recovery. To implement the runtime migration of the worker, we use a novel serialization algorithm that captures the web worker state where webassembly functions and JavaScript objects are intermingled. Experimental result showed that our system could successfully migrate a non-trivial web worker running webassembly-version OpenCV within a few seconds, and achieved up to 8.4x speedup compared to offloading of pure JavaScript.