Go chan bool loop vs. sync.WaitGroup bench

main_test.go

package main

import (
	"sync"
	"testing"
)

func immediateWG(wg *sync.WaitGroup) {
	wg.Done()
}

func Benchmark0GoRoutineWG(b *testing.B) {
	for i := 0; i < b.N; i++ {
		var wg sync.WaitGroup
		wg.Wait()
	}
}

func Benchmark1GoRoutineWG(b *testing.B) {
	for i := 0; i < b.N; i++ {
		var wg sync.WaitGroup
		wg.Add(1)
		go immediateWG(&wg)
		wg.Wait()
	}
}

func Benchmark10GoRoutineWG(b *testing.B) {
	for i := 0; i < b.N; i++ {
		var wg sync.WaitGroup
		for i := 0; i < 10; i++ {
			wg.Add(1)
			go immediateWG(&wg)
		}
		wg.Wait()
	}
}

func Benchmark100GoRoutineWG(b *testing.B) {
	for i := 0; i < b.N; i++ {
		var wg sync.WaitGroup
		for i := 0; i < 100; i++ {
			wg.Add(1)
			go immediateWG(&wg)
		}
		wg.Wait()
	}
}

func immediateCh(ch chan bool) {
	ch <- true
}

func Benchmark1GoRoutineCh(b *testing.B) {
	for i := 0; i < b.N; i++ {
		ch := make(chan bool)
		go immediateCh(ch)
		<-ch
	}
}

func Benchmark10GoRoutineCh(b *testing.B) {
	for i := 0; i < b.N; i++ {
		ch := make(chan bool)
		for i := 0; i < 10; i++ {
			go immediateCh(ch)
		}
		for i := 0; i < 10; i++ {
			<-ch
		}
	}
}

func Benchmark100GoRoutineCh(b *testing.B) {
	for i := 0; i < b.N; i++ {
		ch := make(chan bool)
		for i := 0; i < 100; i++ {
			go immediateCh(ch)
		}
		for i := 0; i < 100; i++ {
			<-ch
		}
	}
}

$go test -benchmem -bench .
goos: darwin
goarch: amd64
Benchmark0GoRoutineWG-8     	50000000	        22.9 ns/op	      16 B/op	       1 allocs/op
Benchmark1GoRoutineWG-8     	 3000000	       539 ns/op	      16 B/op	       1 allocs/op
Benchmark10GoRoutineWG-8    	  500000	      3431 ns/op	      16 B/op	       1 allocs/op
Benchmark100GoRoutineWG-8   	   50000	     31071 ns/op	      16 B/op	       1 allocs/op
Benchmark1GoRoutineCh-8     	 3000000	       493 ns/op	      96 B/op	       1 allocs/op
Benchmark10GoRoutineCh-8    	  200000	      9723 ns/op	      96 B/op	       1 allocs/op
Benchmark100GoRoutineCh-8   	   20000	     61699 ns/op	      96 B/op	       1 allocs/op
PASS
ok  	_/Users/rob	12.912s