source: benchmark/readyQ/bench.go @ 1205b3e

package main

import (
        "bufio"
        "flag"
        "fmt"
        "log"
        "os"
        "runtime"
        "runtime/pprof"
        "sync/atomic"
        "time"
)

var clock_mode bool
var threads_left int64
var stop int32
var duration float64
var stop_count uint64
var nprocs int
var nthreads int

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 bench_init() func() {
        nprocsOpt := flag.Int("p", 1, "The number of processors")
        nthreadsOpt := flag.Int("t", 1, "The number of threads")
        durationOpt := flag.Float64("d", 0, "Duration of the experiment in seconds")
        stopOpt := flag.Uint64("i", 0, "Duration of the experiment in iterations")
        cpuprofile := flag.String("cpuprofile", "", "write cpu profile to file")

        flag.Parse()

        nprocs = *nprocsOpt
        nthreads = *nthreadsOpt
        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 (default)\n", duration)
        }

        runtime.GOMAXPROCS(nprocs)

        if (*cpuprofile) != "" {
                f, err := os.Create(*cpuprofile)
                if err != nil {
                    log.Fatal(err)
                }
                pprof.StartCPUProfile(f)
        }

        return func() {
                if (*cpuprofile) != "" {
                        pprof.StopCPUProfile()
                }
        }
}