实现go并发的三种方式

package main

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

// 方法一： 通过sync.WaitGroup + chan自定义

var tokens chan struct{}
var wg sync.WaitGroup

func fprint(num int) {

    defer wg.Done()
    time.Sleep(10 * time.Microsecond)
    <-tokens

    fmt.Println(num)

}

func main() {
    t1 := time.Now()
    tokens = make(chan struct{}, 500) // 并发数量

    for num := 0; num < 100000; num++ {

        fmt.Printf("插入一个%d
", num)
        wg.Add(1)
        tokens <- struct{}{}
        // fmt.Printf("队列长度----%d
", len(tokens))
        go fprint(num)

    }
    wg.Wait()
    t := time.Since(t1)
    fmt.Println(t)

}

package main

import (
    "fmt"
    "sync"

    "time"

    "github.com/panjf2000/ants/v2"
)

func myFunc(num int32) {
    time.Sleep(10 * time.Microsecond)

    fmt.Println(num)
}

func demoFunc(num int32) {
    time.Sleep(10 * time.Microsecond)

    fmt.Println(num)
}

func main() {
    t1 := time.Now()
    defer ants.Release()

    runTimes := 100000
    var wg sync.WaitGroup

    //方法二：使用ants默认数量的goroutinues,打开源码可以看到链接池的容量大小为: math.MaxInt32*（2147483647）
    // Use the common pool.
    syncCalculateSum := func(num int32) func() {
        return func() {
            demoFunc(num)
            fmt.Printf("running goroutines: %d
", ants.Running())
            wg.Done()
        }

    }
    for i := 0; i < runTimes; i++ {
        wg.Add(1)
        _ = ants.Submit(syncCalculateSum(int32(i))) //ants.Submit只接收func类型的参数
    }
    wg.Wait()
    // fmt.Printf("running goroutines: %d
", ants.Running())
    fmt.Printf("finish all tasks.
")

    //方法三：使用自定义数量的goroutinues
    // Use the pool with a function,
    // set 475 to the capacity of goroutine pool and 1 second for expired duration.
    p, _ := ants.NewPoolWithFunc(475, func(i interface{}) { // 并发数量475
        myFunc(i.(int32)) //业务函数
        wg.Done()
    }, ants.WithPreAlloc(true))
    defer p.Release()
    // Submit tasks one by one.
    for i := 0; i < runTimes; i++ {
        wg.Add(1)
        fmt.Printf("running goroutines: %d
", p.Running())
        _ = p.Invoke(int32(i)) // 传递业务函数的参数
    }
    wg.Wait()

    fmt.Printf("finish all tasks
")

    t := time.Since(t1)
    fmt.Println(t)
}