test

package main

import (
    "fmt"
    "sync"
    "time"
)

const NTHREADS = 10000

func main() {
    var wg sync.WaitGroup
    start := time.Now()
    wg.Add(NTHREADS)
    for i := 0; i < NTHREADS; i++ {
        go func() {
            defer wg.Done()
            time.Sleep(time.Millisecond * 100)
        }()
    }
    wg.Wait()
    fmt.Println(time.Since(start))
}