package main

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

func sum(id int) {
    var x int64
    for i := int64(0); i < math.MaxUint32; i++ {
        x += i
    }
    println(id, x)
}

func main() {
    t1 := time.Now()
    wg := new(sync.WaitGroup)
    wg.Add(2)

    for i := 0; i < 2; i++ {
        go func(id int) {
            defer wg.Done()
            sum(id)
        }(i)
    }
    wg.Wait()

    t2 := time.Now()
    fmt.Println("消耗时间：", t2.Sub(t1), "秒")

}

package main

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

type HandleFunc func(int)

func Handler(id int, handleFnc HandleFunc, wg *sync.WaitGroup) {
    defer wg.Done()
    handleFnc(id)
}

func HasGoSched(id int) {
    for i := 0; i < 10; i++ {
        fmt.Println(id, i)
        if i == 3 || i == 8 {
            runtime.Gosched()
        }
    }
}

func SayHello(id int) {
    fmt.Println(id, "Hello World!")
}

func OtherProc(id int) {
    for i := 0; i < 10; i++ {
        fmt.Println(id, i)
        if i == 5 {
            runtime.Gosched()
        }
    }
}

func main() {

    t1 := time.Now()

    wg := new(sync.WaitGroup)

    wg.Add(3)

    go Handler(0, HasGoSched, wg)
    go Handler(1, SayHello, wg)
    go Handler(2, OtherProc, wg)

    wg.Wait()

    t2 := time.Now()
    fmt.Println("消耗时间：", t2.Sub(t1), "秒")
}