source: doc/theses/colby_parsons_MMAth/benchmarks/channels/go/daisy_chain/daisy_chain.go

package main

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

var done bool = false;
var total_operations uint64 = 0
var Processors int = 1
var m sync.Mutex

var taskJoin chan int = make(chan int, 2)
var chain chan int = make(chan int, 2 )

func Task() {
        var count uint64 = 0 
        for {
                if done { break }
                <-chain
                chain<-0
                count++;
        }
        
        m.Lock()
        total_operations += count
        m.Unlock()
        taskJoin <- 0
}

func main() {
        switch len( os.Args ) {
                case 2:
                        if os.Args[1] != "d" {                                                  // default ?
                                Processors, _ = strconv.Atoi( os.Args[1] )
                        } // if
                case 1:                                                                                 // use defaults
                default:
                        fmt.Printf( "Invalid args" );
                        os.Exit( 1 );
        } // switch
        runtime.GOMAXPROCS( Processors );

        taskJoin= make(chan int, Processors)
        chain= make(chan int, 2 * Processors )
        
        chain <- 0

        for i := 0; i < Processors; i++ {
                go Task()
        }
                
        // wait 10 seconds
        time.Sleep(time.Second * 10)
        // fmt.Println("prod done\n")
        done = true

        for i := 0; i < Processors; i++ {
                chain <- 0
        }
        for i := 0; i < Processors; i++ {
                <-taskJoin
        }

    fmt.Println(total_operations)
}