goroutine vs channel vs single threading performance

go_test.go

package main

import "testing"

var channel = make(chan []byte, 1024)
var data = make([]byte, 1024)
var sink = []byte{}

func goroutine(data []byte) {
	sink = data
}

func channelroutine(channel <-chan []byte) {
	for data := range channel {
		sink = data
	}
}

func init() {
	go channelroutine(channel)
}

func BenchmarkGoRoutine(b *testing.B) {
	for n := 0; n < b.N; n++ {
		go goroutine(data)
	}
}
func BenchmarkChannel(b *testing.B) {
	for n := 0; n < b.N; n++ {
		channel <- data
	}
}
func BenchmarkNormal(b *testing.B) {
	for n := 0; n < b.N; n++ {
		sink = data
	}
}

results

# MacBook Pro (15-inch, 2017)
# 10.15.4 (19E287)

% go test -bench=.
goos: darwin
goarch: amd64
pkg: test
BenchmarkGoRoutine-8   	 4393114	       271 ns/op
BenchmarkChannel-8     	13652916	        83.2 ns/op
BenchmarkNormal-8      	1000000000	         0.924 ns/op
PASS
ok  	test	3.803s
go test -bench=.  9.47s user 1.58s system 262% cpu 4.211 total