Fable wrote a .NET GC in C#, got within range of the stock GC in 2 days (github.com)

A groundbreaking project has emerged: a fully-featured .NET garbage collector (GC) written entirely in C# that integrates seamlessly into the .NET runtime as a standalone option. This initiative began as an educational framework, evolving into a competitive GC through the involvement of an AI agent named Claude, which autonomously designed, benchmarked, and refined the GC to rival the existing one in .NET. Notably, the new GC achieved extraordinary performance metrics, outperforming the stock GC across multiple benchmarks while using less memory. Significantly, this project showcases innovative techniques such as a unique memory management strategy that avoids object movement, reducing the complexity and cost often associated with traditional GCs. By employing a region-based memory layout, the GC can allocate, reclaim, and interact with memory more efficiently—resulting in shorter pause times during garbage collection operations. Additionally, features such as an adaptive nursery for workload management and a non-pinning memory strategy highlight its practical advantages for performance-intensive applications. As the technological landscape continues to evolve, this advancement not only represents a notable achievement in garbage collection for .NET but also showcases the potential for AI-driven development in creating complex software solutions.