bench_test.go

package benchtest

import (
	"testing"
)

type iface_foo interface {
	foo()
}

type struct_foo struct {
}

func (f struct_foo) foo() {
}

var foovar = struct_foo{}
var pfoovar = &struct_foo{}

func BenchmarkTypeCast(b *testing.B) {
	for i := 0; i < b.N; i++ {
		var _ iface_foo = foovar
	}
}

func BenchmarkPointerTypeCast(b *testing.B) {
	for i := 0; i < b.N; i++ {
		var _ iface_foo = pfoovar
	}
}

func BenchmarkSliceAppend(b *testing.B) {
	var appender = make([]struct_foo, b.N)

	for i := 0; i < b.N; i++ {
		appender = append(appender, foovar)
	}
}

func BenchmarkSliceGrowAndAppend(b *testing.B) {
	// Make length small to force underlying array to grow on appends
	var appender = make([]struct_foo, 2)

	for i := 0; i < b.N; i++ {
		appender = append(appender, foovar)
	}
}

results

$ go test -bench=Bench
testing: warning: no tests to run
PASS
BenchmarkTypeCast		100000000	        11.1 ns/op
BenchmarkPointerTypeCast	2000000000	         0.84 ns/op
BenchmarkSliceAppend		500000000	         2.94 ns/op
BenchmarkSliceGrowAndAppend	500000000	         4.23 ns/op