Performance deep dive

In this approach, we'll find out how to most efficiently validate a number with the Luhn algorithm in Go.

The approaches page lists two idiomatic approaches to this exercise:

1. Using the scrub and validate first appproach
2. Uisng the validate as you go approach

Benchmarks

To benchmark the approaches, we ran the following Benchmark code for each approach:

func BenchmarkValid(b *testing.B) {
	for i := 0; i < b.N; i++ {
		for _, test := range testCases {
			Valid(test.input)
		}
	}
}

and received the following results:

validate as you go
BenchmarkValid-12    	 4668248	       248.4 ns/op	       0 B/op	       0 allocs/op

scrub and validate first
BenchmarkValid-12    	  969022	      1121 ns/op	     352 B/op	      14 allocs/op

Generally, the fewer bytes allocated per op (B/op) the faster (i.e. the fewer ns/op) the implementation. More info on reading benchmarks can be found here.

The fastest is the validate as you go approach.