Interface Performance in Go

Dynamic dispatch in Go incurs a cost because interface calls require a runtime lookup of the concrete method via the interface's itab structure, preventing inlining and adding indirection overhead. To minimize this cost, prefer concrete types for hot paths or use the arena package for bulk allocations to reduce garbage collection pressure, as dynamic dispatch itself cannot be eliminated without changing the type system.

// Costly: Interface call prevents inlining
func Process(i interface{}) {
    i.DoWork() // Runtime lookup required
}

// Faster: Concrete type allows inlining
func ProcessConcrete(c Concrete) {
    c.DoWork() // Compiler can inline this
}

Dynamic dispatch is like asking a receptionist to find the right person to handle your call instead of dialing their direct line. It adds a small delay because the computer has to look up which specific function to run at runtime. You use it for flexibility, but it costs a tiny bit of speed compared to calling a function directly.