[练习]go版的击鼓传花
这个是erlang的一个练习.从前有人用来展现stackelss python的性能如何牛.学习go的goroutine,也照猫画虎来一个.
go的协程有些特别.没有join等待协程结束,所以用了一个结果队列(类似perl)
channel的写入默认也是非缓冲(阻塞方式)的
总体来看,go的协程性能相当之好,即使是go run方式,类似脚本运行,也比python,perl快不少
编程的风格和c很象
数组作为函数参数,这块没有具体研究是传值还是传指针
想当然地按c的方式处理了/*
go版的击鼓传花（erlang和stackless的经典例子）
由n个节点组成一个环状网络，在上面传送共m个消息。
将每个消息（共m个），逐个发送给1号节点。
第1到n-1号节点在接收到消息后，都转发给下一号节点。
第n号节点每次收到消息后，不再继续转发。
当m个消息都从1号逐个到达第n号节点时，认为全部处理结束。
每次执行时设定n=300，m=10000
*/
package main
import (
"flag"
"fmt"
//"os"
"strconv"
)
var n,m int
//3.定义节点(协程)
func node(i int,ch []chan int,result chan int){
for{
msg:= <-ch
//fmt.Println("node ", i," got msg ",msg)
if i>=n-1 {
//fmt.Println("msg ", msg," reached last node ",i)
if msg>=m-1 {
fmt.Println("final msg send back")
result <- msg
}
}else{
//fmt.Println("node ", i," pass msg",msg," to next node")
ch <- msg
}
}
}
func main() {
//1.输入参数处理
flag.Parse()
args := flag.Args()
if args != nil&&len(args) > 0 {
var err error
n,err = strconv.Atoi(args)
if err != nil {
n = 300
}
m,err = strconv.Atoi(args)
if err != nil {
m = 10000
}
} else {
n = 300
m=10000
}
fmt.Println("n=", n,"m=",m)
//2.创建队列/channel
//用于结束.go没有join之类的等待同步函数
result := make(chan int)
chs := make([]chan int,n)
for i := 0; i < n; i++ {
chs = make(chan int)
//5.启动节点(创建协程)
go node(i,chs,result)
}
//4.初始化消息
//go的channel写也是阻塞的
for i := 0; i < m; i++ {
//fmt.Println("put msg ", i," intochannel 0")
chs <- i
}
//等待结束
<-result
}
//测试结果
/*
192.168.6.150
-bash-3.2$ go build ring.go
-bash-3.2$ time ./ring 3000 100
n= 3000 m= 100
final msg send back
real 0m0.356s
user 0m0.229s
sys 0m0.020s
-bash-3.2$ time go run ./ring.go 3000 100
n= 3000 m= 100
final msg send back
real 0m0.919s
user 0m0.631s
sys 0m0.079s
-bash-3.2$
-bash-3.2$ time ./ring 10000 100
n= 10000 m= 100
final msg send back
real 0m1.113s
user 0m0.774s
sys 0m0.038s
-bash-3.2$ time go run ./ring.go 10000 100
n= 10000 m= 100
final msg send back
real 0m1.747s
user 0m1.276s
sys 0m0.093s
-bash-3.2$ time ./ring 100 10000
n= 100 m= 10000
final msg send back
real 0m0.692s
user 0m0.493s
sys 0m0.004s
-bash-3.2$
-bash-3.2$ time go run ./ring.go 100 10000
n= 100 m= 10000
final msg send back
real 0m1.329s
user 0m0.903s
sys 0m0.074s
-bash-3.2$
-bash-3.2$ time go run ./ring.go 300 10000
n= 300 m= 10000
final msg send back
real 0m2.628s
user 0m1.924s
sys 0m0.073s
-bash-3.2$ time ./ring 300 10000
n= 300 m= 10000
final msg send back
real 0m1.922s
user 0m1.505s
sys 0m0.018s
*/
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