Project Quantum is a major rewrite of Firefox’s internals to make Firefox fast. We’re swapping in parts from our experimental browser, Servo, and making massive improvements to other parts of the engine. The first major component from Servo—a new CSS engine called Quantum CSS (previously known as Stylo)—is now available for testing in our Nightly version. It brings together state-of-the-art innovations from four different browsers to create a new super CSS engine.
Scheduling is a significant piece of Project Quantum, which focuses on making Firefox more responsive, especially when lots of tabs are open. In this article, we describe problems we identified in multi-tab browsing, the solutions we figured out, the current status of Quantum DOM, and opportunities for contribution to the project.
What makes work on performance so challenging and why is it so important to include the user from the very beginning? This article explores the difference between technical and perceived performance, and describes an approach to testing and measurement that correlates the user's quality of experience with characteristics that engineers can benchmark.