Is it a good idea to create a new thread every 10 frames in Unity?

Question

private void RunEveryTenFrames(Color32[] pixels, int width, int height)
    {
        var thread = new Thread(() =>
        {
            Perform super = new HeavyOperation();
            if (super != null)
            {
                Debug.Log("Result: " + super);
                ResultHandler.handle(super);
            }
        });
        thread.Start();
    }

I'm running this function every 10 frames in Unity. Is this a bad idea. Also, when I try to add thread.Abort() inside the thread, it says thread is not defined and can't use local variable before it's defined error.

Well, if the operation takes longer than the time required to show 10 frames, you're going to have a problem. Either way, this is an opinion based question really, only you can tell if it's the right way to achieve your goal (though I'm almost certain there are better ways) — DavidG, Feb 22 '18 at 12:03
You can define thread as a global private Thread and then you can Abort it before start new thread — MBS, Feb 22 '18 at 12:03
@DavidG I'm trying to parse QRCodes from the frame pixels using ZXing QRCodeReader. What kind of better ways am I looking for? I'm new to multi-threading. — Faizuddin Mohammed, Feb 22 '18 at 12:10
But, I don't want the new thread to *not* run when there is a previous thread running. — Faizuddin Mohammed, Feb 22 '18 at 12:10
@Lestat coroutines are synchronous and my frames are highly affected with coroutines. — Faizuddin Mohammed, Feb 22 '18 at 12:11
@Lestat I'm not using any Unity specific APIs inside threading either. — Faizuddin Mohammed, Feb 22 '18 at 12:12

score 2 · Accepted Answer · answered Feb 22 '18 at 12:52

Is it a good idea to create a new thread every 10 frames in Unity?

No. 10 frames is too small for repeatedly creating new Thread.

Creating new Thread will cause overhead each time. It's not bad when done once in a while. It is when done every 10 frames. Remember this is not every 10 seconds. It is every 10 frames.

Use ThreadPool. By using ThreadPool with ThreadPool.QueueUserWorkItem, you are re-using Thread that already exist in the System in instead of creating new ones each time.

Your new RunEveryTenFrames function with ThreadPool should look something like this:

private void RunEveryTenFrames(Color32[] pixels, int width, int height)
{
    //Prepare parameter to send to the ThreadPool
    Data data = new Data();
    data.pixels = pixels;
    data.width = width;
    data.height = height;

    ThreadPool.QueueUserWorkItem(new WaitCallback(ExtractFile), data);
}

private void ExtractFile(object a)
{
    //Retrive the parameters
    Data data = (Data)a;

    Perform super = new HeavyOperation();
    if (super != null)
    {
        Debug.Log("Result: " + super);
        ResultHandler.handle(super);
    }
}

public struct Data
{
    public Color32[] pixels;
    public int width;
    public int height;
}

I you ever need to call into Unity's API or use Unity's API from this Thread, see my other post or how to do that.

Yes, you can also use Task but it is only supported in recent Unity 2017 release. Won't work on versions under that. — Programmer, Feb 22 '18 at 12:58
No. ThreadPool is basically a wrapper again Threads and will manage Threads or you. It will create a Thread if one do not exist yet and then re-use them each time you call that function again. You may want to use `ThreadPool.SetMaxThreads` to set limit on the Thread amount so that it doesn't go cuckoo on mobile devices. — Programmer, Feb 22 '18 at 13:07

Is it a good idea to create a new thread every 10 frames in Unity?

1 Answers1