What algorithm does the Go Garbage Collector use? How does it work in general?

The Garbage Collector (GC) in Go is implemented as a three-phase, concurrent, trigger-based garbage collector with a tracing algorithm (tracing GC).

Main features and working algorithm:

1. Three-phase approach: The GC goes through three main phases — marking (mark), pause (stop-the-world) for synchronization, and sweeping (sweep).

2. Marking (Mark): The GC starts from root objects (root set), marking all reachable objects. This process occurs concurrently with the application's work, minimizing pauses.

3. Pause (Stop-the-world): A short pause during which the application is stopped to ensure data consistency and complete marking.

4. Sweeping (Sweep): Unused objects are freed after marking.

5. Concurrency: The GC runs in parallel with the application, reducing delays.

6. Trigger: Garbage collection is initiated when the allocated memory reaches a certain threshold, usually related to the current volume of live objects.

Thus, Go's GC provides automatic memory management with minimal pauses, which is important for high-performance and network applications.

Here's an example of how GC works in Go:

// Memory is allocated via new or make
obj := new(MyStruct)
// GC periodically runs to free unused objects

Internal implementation details may change, but the concept of concurrent tracing GC remains fundamental.