Golang的纤程耗费

每纤程groutine 大约8K 内存

// Concurrent computation of pi.

// See https://goo.gl/la6Kli.

//

// This demonstrates Go's ability to handle

// large numbers of concurrent processes.

// It is an unreasonable way to calculate pi.

package main

import (

"bufio"

"fmt"

"math"

"os"

"sync"

)

var w sync.WaitGroup

func main() {

fmt.Println(pi(10000))

}

// pi launches n goroutines to compute an

// approximation of pi.

func pi(n int) float64 {

ch := make(chan float64)

ch2 := make(chan float64)

for k := 0; k <= n; k++ {

w.Add(1)

go term(ch, ch2, float64(k))

}

f := 0.0

for k := 0; k <= n; k++ {

f += <-ch

}

reader := bufio.NewReader(os.Stdin)

reader.ReadLine()

for k := 0; k <= n; k++ {

ch2 <- 1.0

}

w.Wait()

return f

}

func term(ch, ch2 chan float64, k float64) {

ch <- 4 * math.Pow(-1, k) / (2*k + 1)

<-ch2

w.Done()

}

1万线程 内存 87M,

10万线程 内存861M  0.635301秒创建线程 ，创建线程花费很低。