In the following example, we combine the fact that goroutines are not garbage collec‐ ted with the runtime’s ability to introspect upon itself and measure the amount of memory allocated before and after goroutine creation!

goroutines.go

package main

import (
	"fmt"
	"runtime"
	"sync"
)

func main() {
	memConsumed := func() uint64 {
		runtime.GC()
		var s runtime.MemStats
		runtime.ReadMemStats(&s)
		return s.Sys
	}

	var c <-chan interface{}
	var wg sync.WaitGroup
	noop := func() { wg.Done(); <-c }

	const numGoroutines = 1e4
	wg.Add(numGoroutines)
	before := memConsumed()
	for i := numGoroutines; i > 0; i-- {
		go noop()
	}
	wg.Wait()

	after := memConsumed()
	fmt.Printf("%.3fkb", float64(after-before)/numGoroutines/1000)
}