Redox OS Moves to the EEVDF Scheduler: 2.6× Throughput Gain

Redox OS, an operating system written entirely from scratch in the Rust language, has switched to a task scheduler built on the EEVDF (Earliest Eligible Virtual Deadline First) scheme. According to the developers, this delivered a 2.6× gain in throughput and a 782× improvement in the fairness of CPU time distribution.

The work on implementing EEVDF for Redox OS was carried out by Akshit Gaur as part of the current season of the Redox Summer of Code program. The system previously used the DWRR (Deficit Weighted Round Robin) scheduler, and the move to EEVDF, the team says, led to noticeable improvements across several fronts at once.

Beyond the throughput and fairness gains already mentioned, context-switch time was cut by 82%. The combined effect, as noted on the blog at Redox-OS.org, shows up as a smoother desktop experience and an overall more responsive system.

Gaur himself sums it up tersely: “EEVDF was worth it.” The phrasing sounds matter-of-fact, but behind it lies a difference that is quite tangible for the user — the kind that separates a system that simply works from a system that is a pleasure to work with.

It is worth recalling that EEVDF is no exotic invention: the very same approach underpins the modern Linux kernel scheduler, where it arrived as a replacement for the familiar CFS. So Redox OS, an experimental microkernel system, is moving in line with today's widely accepted solutions — but implementing them on its own foundation, one made memory-safe thanks to Rust.

Redox OS remains a research project, yet results like these show that an operating system built from scratch in Rust is capable not only of demonstrating the concept of safety but also of achieving competitive performance.

Source: Phoronix