Tuning garbage collection

The Go garbage collector (GC) is surprisingly simple if you’re coming from a background of other garbage-collected languages such as Java, which has a seemingly unlimited number of ways to tune garbage collection. There are a very limited number of ways to tune the GC, so we'll focus on the two primary ways: the GOGC and GOMEMLIMIT environment variables.

Until recently (Go 1.19), the GOGC environment variable was the only supported way to control garbage collection behavior when running a Go program. Effectively, the way that it works is by setting a percentage of how much the live heap size (memory) can increase from the previous garbage collection before the GC kicks in to mark and reclaim memory.

Note

This is an intentional oversimplification as other things, such as the memory size of goroutine stacks and global pointers, can also contribute to the overall memory size and are included in the percentage that memory can be increased...