Go Optimization Guide

Every perf guide recommends to minimize allocations to reduce GC times, but if you look at pprof of a Go app, GC mark phase is what takes time, not GC sweep. GC mark always starts with known live roots (goroutine stacks, globals, etc) and traverse references from there colouring every pointer. To minimize GC time it is best to avoid _long living_ allocations. Short lived allocations, those which GC mark phase will never reach, has almost neglible effect on GC times.

Allocations of any kind have an effect on triggering GC earlier, but in real apps it is almost hopeless to avoid GC, except for very carefully written programs with no dependenciesm, and if GC happens, then reducing GC mark times gives bigger bang for the buck.

Its worth calling out that abstractions can kill you in unexpected ways with go.

Anytime you use an interface it forces a heap allocation, even if the object is only used read only and within the same scope. That includes calls to things like fmt.Printf() so doing a for loop that prints the value of i forces the integer backing i to be heap allocated, along with every other value that you printed. So if you helpfully make every api in your library use an interface you are forcing the callers to use heap allocations for every single operation.