Call a syscall in a loop, optionally limiting the number of calls per second

syscall_stress.go

package main

import (
	"sync/atomic"
	"fmt"
	"os"
	"strconv"
	"syscall"
	"time"
)

// Usage: helper <rate>
// helper 5000 for 5000 calls per second
func main() {

	rate := 0
	if len(os.Args) > 1 {
		var err error
		rate, err = strconv.Atoi(os.Args[1])
		if err != nil || rate <= 0 {
			fmt.Fprintln(os.Stderr, "Bad rate:", rate, err)
			os.Exit(1)
		}
		fmt.Fprintf(os.Stderr, "Starting syscall loop [rate=%d/s]\n", rate)
	} else {
		fmt.Fprintln(os.Stderr, "Starting syscall loop")
	}

	var counter, prev uint64
	var prevTime time.Time

	go func() {
		delay := time.Second
		if rate > 0 {
			delay = time.Second / time.Duration(rate)
		}

		next := time.Now().Add(delay)
		for {
			if rate > 0 {
				if time.Now().Before(next) {
					time.Sleep(time.Until(next))
				}
				next = next.Add(delay)
			}
			syscall.Accept(-1)
			atomic.AddUint64(&counter, 1)
		}
	}()

	tick := time.NewTicker(time.Second / 2)

	for _ = range tick.C {
		count := atomic.LoadUint64(&counter)
		now := time.Now()
		delta := count - prev
		if prev != 0 {
			secs := float64(now.Sub(prevTime)) / float64(time.Second)
			fmt.Fprintf(os.Stderr, "\rCalled %d times [%f c/s]   ", count, float64(delta) / secs)
		}
		prev = count
		prevTime = now
	}
}