source: benchmark/readyQ/cycle.go@ 7a2a3af

package main

import (
        "bufio"
        "flag"
        "fmt"
        "os"
        "runtime"
        "sync/atomic"
        "time"
        "golang.org/x/text/language"
        "golang.org/x/text/message"
)

var clock_mode bool
var threads_left int64
var stop int32
var duration float64
var stop_count uint64

func fflush(f *bufio.Writer) {
        defer f.Flush()
        f.Write([]byte("\r"))
}

func wait(start time.Time, is_tty bool) {
        f := bufio.NewWriter(os.Stdout)
        tdur := time.Duration(duration)
        for true {
                time.Sleep(100 * time.Millisecond)
                end := time.Now()
                delta := end.Sub(start)
                if is_tty {
                        fmt.Printf(" %.1f",delta.Seconds())
                        fflush(f)
                }
                if clock_mode && delta >= (tdur * time.Second) {
                        break
                } else if !clock_mode && atomic.LoadInt64(&threads_left) == 0 {
                        break
                }
        }
}

func partner(result chan uint64, mine chan int, next chan int) {
        count := uint64(0)
        for true {
                <- mine
                next <- 0
                count += 1
                if  clock_mode && atomic.LoadInt32(&stop) == 1 { break }
                if !clock_mode && count >= stop_count { break }
        }

        atomic.AddInt64(&threads_left, -1);
        result <- count
}

func main() {
        var nprocs int
        var nthreads int
        var ring_size int

        nprocsOpt := flag.Int("p", 1, "The number of processors")
        nthreadsOpt := flag.Int("t", 1, "The number of threads")
        ring_sizeOpt := flag.Int("r", 2, "The number of threads per cycles")
        durationOpt := flag.Float64("d", 0, "Duration of the experiment in seconds")
        stopOpt := flag.Uint64("i", 0, "Duration of the experiment in iterations")

        flag.Parse()

        nprocs = *nprocsOpt
        nthreads = *nthreadsOpt
        ring_size = *ring_sizeOpt
        duration = *durationOpt
        stop_count = *stopOpt

        if duration > 0 && stop_count > 0 {
                panic(fmt.Sprintf("--duration and --iterations cannot be used together\n"))
        } else if duration > 0 {
                clock_mode = true
                stop_count = 0xFFFFFFFFFFFFFFFF
                fmt.Printf("Running for %f seconds\n", duration)
        } else if stop_count > 0 {
                clock_mode = false
                fmt.Printf("Running for %d iterations\n", stop_count)
        } else {
                duration = 5
                clock_mode = true
                fmt.Printf("Running for %f seconds\n", duration)
        }

        runtime.GOMAXPROCS(nprocs)
        tthreads := nthreads * ring_size
        threads_left = int64(tthreads)

        result := make(chan uint64)
        channels := make([]chan int, tthreads)
        for i := range channels {
                channels[i] = make(chan int, 1)
        }

        for i := 0; i < tthreads; i++ {
                pi := (i + nthreads) % tthreads
                go partner(result, channels[i], channels[pi])
        }
        fmt.Printf("Starting\n");

        atomic.StoreInt32(&stop, 0)
        start := time.Now()
        for i := 0; i < nthreads; i++ {
                channels[i] <- 0
        }
        wait(start, true);

        atomic.StoreInt32(&stop, 1)
        end := time.Now()
        delta := end.Sub(start)

        fmt.Printf("\nDone\n")

        global_counter := uint64(0)
        for i := 0; i < tthreads; i++ {
                global_counter += <- result
        }

        p := message.NewPrinter(language.English)
        p.Printf("Duration (ms)       : %f\n", delta.Seconds());
        p.Printf("Number of processors: %d\n", nprocs);
        p.Printf("Number of threads   : %d\n", tthreads);
        p.Printf("Cycle size (# thrds): %d\n", ring_size);
        p.Printf("Yields per second   : %18.2f\n", float64(global_counter) / delta.Seconds())
        p.Printf("ns per yields       : %18.2f\n", float64(delta.Nanoseconds()) / float64(global_counter))
        p.Printf("Total yields        : %15d\n", global_counter)
        p.Printf("Yields per threads  : %15d\n", global_counter / uint64(tthreads))
        p.Printf("Yields per procs    : %15d\n", global_counter / uint64(nprocs))
        p.Printf("Yields/sec/procs    : %18.2f\n", (float64(global_counter) / float64(nprocs)) / delta.Seconds())
        p.Printf("ns per yields/procs : %18.2f\n", float64(delta.Nanoseconds()) / (float64(global_counter) / float64(nprocs)))

}