CODEWITHSUNDEEP
c#.netperformance
Alex
Alex

Reputation: 77329

C#: Create CPU Usage at Custom Percentage

I'm looking to test system responsiveness etc. on a few machines under certain CPU usage conditions. Unfortunately I can only create ~100% usage (infinite loop) or not enough CPU usage (I'm using C#).

Is there any way, in rough approximation, as other tasks are running on the system as well, to create CPU usage artificially at 20, 30, 40% (and so forth) steps?

I understand that there are differences between systems, obviously, as CPU's vary. It's more about algorithms/ideas on customizable CPU intensive calculations that create enough usage on a current CPU without maxing it out that I can tweak them then in some way to adjust them to create the desired percentage.

Upvotes: 7

Views: 3727

Answers (6)

Theodor Zoulias
Theodor Zoulias

Reputation: 43400

Here is a function that utilizes all available processors/cores to a customizable percent, and can be cancelled at any time by the calling code.

private static CancellationTokenSource StressCPU(int percent)
{
    if (percent < 0 || percent > 100) throw new ArgumentException(nameof(percent));
    var cts = new CancellationTokenSource();
    for (int i = 0; i < Environment.ProcessorCount; i++)
    {
        new Thread(() =>
        {
            var stopwatch = new Stopwatch();
            while (!cts.IsCancellationRequested)
            {
                stopwatch.Restart();
                while (stopwatch.ElapsedMilliseconds < percent) { } // hard work
                Thread.Sleep(100 - percent); // chill out
            }
        }).Start();
    }
    return cts;
}

Usage example:

var cts = StressCPU(50);
Thread.Sleep(15000);
cts.Cancel();

Result:

CPU usage

Upvotes: 1

Colin Gravill
Colin Gravill

Reputation: 4274

You could add a threaded timer that wakes up on an interval and does some work. Then tweak the interval and amount of work until you approximate the load you want.

    private void button1_Click(object sender, EventArgs e)
    {
        m_timer = new Timer(DoWork);
        m_timer.Change(TimeSpan.Zero, TimeSpan.FromMilliseconds(10));
    }

    private static void DoWork(object state)
    {
        long j = 0;
        for (int i = 0; i < 2000000; i++)
        {
            j += 1;
        }
        Console.WriteLine(j);
    }

alt text

With that and tweaking the value of the loop I was able to add 20%, 60% and full load to my system. It will scale for multiple cores using additional threads for more even load.

Upvotes: 4

Kal
Kal

Reputation: 378

The utility provides a simple slider bar user interface that allows you to place an arbitrary load on the processor(s) in your system. Automatically detects and handles multiple processors.

Worked very well for me when I downloaded it this morning.

Upvotes: 2

Bubblewrap
Bubblewrap

Reputation: 7516

This then?

    DateTime lastSleep = DateTime.Now;            
    while (true)
    {
        TimeSpan span = DateTime.Now - lastSleep;
        if (span.TotalMilliseconds > 700)
        {
            Thread.Sleep(300);
            lastSleep = DateTime.Now;
        }
    }

You could use smaller numbers to get a more steady load....as long as the ratio is whatever you want. This does only use one core though, so you might have to do this in multiple threads.

Upvotes: 5

Erik
Erik

Reputation:

When you tried using sleep, did you do like this or just put the sleep inside the actual loop? I think this will work.

while(true)
{
  Thread.Sleep(0);
  for(int i=0;i<veryLargeNumber; i++)
  {
      //maybe add more loops here if looping to veryLargeNumber goes to quickly
      //also maybe add some dummy operation so the compiler doesn't optimize the loop away
  }
}

Upvotes: 0

Preet Sangha
Preet Sangha

Reputation: 65476

Not done this - but you could try working out prioritised threads running in multiple programs.

Upvotes: 0

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