wasimoff

This is the codebase for the result of my Master's thesis "Opportunistic Distributed Computation Offloading using WebAssembly". It is a computation offloading platform which uses WebAssembly as its executable format and sends requests to participating browser clients through a central broker over WebTransport streams.

The condensed paper has been accepted on the *LESS'24 (aka. STARLESS'24) that is co-located with the IEEE Percom'24. Its title is Wasimoff: Distributed Computation Offloading Using WebAssembly in the Browser.

Essential roles

The three essential roles Broker, WebProvider and Client can be found in their respective subdirectories.

• The Broker is a central entity to which all Providers connect and which then distributes tasks among them. Clients talk to the Broker to upload executables and queue tasks. It is written in Go and uses WebTransport connections over QUIC for the Providers.
• WebProviders are the participants that share their resources with the network. An important goal of this thesis was to implement the Provider entirely on the Web platform API, so it can run in the browser simply by opening a web page. It is written in Vue.js and uses Workers to execute the WebAssembly modules concurrently.
• The Client interface is simply an HTTP API, therefore only an example of using curl in Bash is shown here. It contains a number of examples on how to write offloading configurations.

WASI applications

The WebAssembly System Interface (WASI) was chosen as an abstraction layer for the offloaded tasks and the subdirectory wasi-apps/ contains a number of example applications, which use this compilation target to show off its versatility and serve as example workloads during the evaluation.

• ffmpeg is a compilation of the popular FFmpeg toolkit to WebAssembly. It can be used to transcode videos in a browser tab.
• helloworld is a collection of different languages (Rust, TinyGo, WAT) targeting basic features of the WASI target wasm32-wasi.
• travelling_salesman is an implementation of the .. you guessed it .. Travelling Salesman Problem in Rust. It can be compiled to various native binary formats but also to WASI and it serves as the computational workload in all of the evaluation runs.
• web-demo is a minimal example of using the browser_wasi_shim to execute WebAssembly binaries with environment variables and commandline arguments in the browser.

Evaluation

The evaluation subdirectory contains an extensive Ansible configuration to deploy a testing environment on the Hetzner Cloud, as well as various further subdirectories, that describe the performed evaluations and contain result data. Each evaluation has a separate README with information on how to reproduce the results.

Experiments

The experiments directory contains various experiments and evaluations of pieces of the networking stack that were considered.

Containerized deployment

This repository includes a multi-stage Dockerfile, which:

• compiles the broker binary in a golang:1.21-bookworm image,
• compiles the webprovider frontend dist in a node:20-bookworm image,
• copies both in a barebones alpine image to save space and
• prepares another image with a headless Chromium to act as the provider.

Usage notes for these container images have been offloaded *ahem* to README_containerized.md.