some benchmark related to golang

goBenchmark

package main

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

func main() {

    wg := sync.WaitGroup{}

    x := 0
    channel := make(chan int, 20000000)
    mtx := sync.Mutex{}

    for i := 0; i < 1000000; i++ {
        wg.Add(1)
        go func() {
            defer wg.Done()
            mtx.Lock()
            x++
            mtx.Unlock()
            channel <- x
        }()
    }

    wg.Wait()
    fmt.Println("x ", x)
}

On a 2015 MacBook Pro 15,

• without lock (of course, result not correct), the performance of creating 1000000 goroutines is around 0.5s.
• with lock, the performance is even slightly better, it is also around 0.5s.
• adding channel, the run time will increase to 0.8s.
• adding both channel and mtx, the performance will increase to 1s.