Linux Features Loved By Microsoft Engineers Working On WSL2

In addition to Microsoft having a significant present at last week's Linux Security Summit, there were also multiple Microsoft engineers at the Linux Foundation's Open-Source Summit that was also taking place in Vancouver. Among the Microsoft Linux talks this week was a presentation on the Linux kernel usage by WSL2 -- including how it's moving closer to a mainline/upstream status and also mentions of Linux kernel features loved by Microsoft's engineering team.

Allen Pais and Kelsey Steele both of Microsoft presented on the WSL2 kernel -- both in the context of the traditional Windows Subsystem for Linux as well as Windows Subsystem for Android. In the presentation they covered the WSL/WSA architecture, how they track the Linux LTS kernel releases, and their upstream kernel contributions. Some of their upstream contributions are around continued testing of Linux kernel release candidates, improving testing of the kernel, and a goal of increasing their upstream contributions.

Those curious about the modifications still being carried by Microsoft to their WSL2 Linux kernel can see this GitHub repository where they continue to stage their changes and routinely release new versions. Their latest WSL2 builds are already moved onto Linux 6.1 LTS.

It was also interesting to see some of the features Microsoft engineers "absolutely love" about Linux. Mentioned were Multi-Gen LRU (MGLRU), Profile Guided Optimizations (PGO) for compiler optimizations, VirtIO-GPU for virtual GPU handling, suspend-to-disk, and Google's development model.

Those curious about this Microsoft WSL2 presentation from the 2023 Open-Source Summit North America can find the slide deck and more details at the OSSNA2023 site.