How to execute method n-times in a second?
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Hi, I have WindowsForms application where I should execute method n-times in a second. The method should be executed inside of its own separate thread. I use thread pool for that purpose. UI contains text box where I enter the number of times of execution and button, which I click to start processing. I've tried to use System.Windows.Forms.Timer but it works for smaller number of executions (~ up to 100). It works means for example 50 calls can be done in 1 second. When the number of calls is growing they can't be executed in 1 second. They need more and more time. The code looks as follows:
private int count = 0; private int tps; public Form1() { InitializeComponent(); ThreadPool.SetMaxThreads(500, 500); } private void button1\_Click(object sender, EventArgs e) { listBox1.Items.Clear(); timer1.Enabled = true; tps = Int32.Parse(textBox1.Text); timer1.Interval = 1000 / tps; timer1.Start(); label1.Text = "Start time: " + DateTime.Now.ToString("hh:mm:ss.fff"); label2.Text = "End time: "; } private void timer1\_Tick(object sender, EventArgs e) { ThreadPool.QueueUserWorkItem(new WaitCallback(DoWork)); } private void DoWork(object stateInfo) { count++; listBox1.Items.Add(count); if (count == tps) { count = 0; timer1.Stop(); label2.Text = label2.Text + " " + DateTime.Now.ToString("hh:mm:ss.fff"); timer1.Enabled = false; } label3.Text = listBox1.Items.Count.ToString(); }Do you have an idea how I can resolve this issue? Thank you in advance. Regards, Goran
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Hi, I have WindowsForms application where I should execute method n-times in a second. The method should be executed inside of its own separate thread. I use thread pool for that purpose. UI contains text box where I enter the number of times of execution and button, which I click to start processing. I've tried to use System.Windows.Forms.Timer but it works for smaller number of executions (~ up to 100). It works means for example 50 calls can be done in 1 second. When the number of calls is growing they can't be executed in 1 second. They need more and more time. The code looks as follows:
private int count = 0; private int tps; public Form1() { InitializeComponent(); ThreadPool.SetMaxThreads(500, 500); } private void button1\_Click(object sender, EventArgs e) { listBox1.Items.Clear(); timer1.Enabled = true; tps = Int32.Parse(textBox1.Text); timer1.Interval = 1000 / tps; timer1.Start(); label1.Text = "Start time: " + DateTime.Now.ToString("hh:mm:ss.fff"); label2.Text = "End time: "; } private void timer1\_Tick(object sender, EventArgs e) { ThreadPool.QueueUserWorkItem(new WaitCallback(DoWork)); } private void DoWork(object stateInfo) { count++; listBox1.Items.Add(count); if (count == tps) { count = 0; timer1.Stop(); label2.Text = label2.Text + " " + DateTime.Now.ToString("hh:mm:ss.fff"); timer1.Enabled = false; } label3.Text = listBox1.Items.Count.ToString(); }Do you have an idea how I can resolve this issue? Thank you in advance. Regards, Goran
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Hi, I have WindowsForms application where I should execute method n-times in a second. The method should be executed inside of its own separate thread. I use thread pool for that purpose. UI contains text box where I enter the number of times of execution and button, which I click to start processing. I've tried to use System.Windows.Forms.Timer but it works for smaller number of executions (~ up to 100). It works means for example 50 calls can be done in 1 second. When the number of calls is growing they can't be executed in 1 second. They need more and more time. The code looks as follows:
private int count = 0; private int tps; public Form1() { InitializeComponent(); ThreadPool.SetMaxThreads(500, 500); } private void button1\_Click(object sender, EventArgs e) { listBox1.Items.Clear(); timer1.Enabled = true; tps = Int32.Parse(textBox1.Text); timer1.Interval = 1000 / tps; timer1.Start(); label1.Text = "Start time: " + DateTime.Now.ToString("hh:mm:ss.fff"); label2.Text = "End time: "; } private void timer1\_Tick(object sender, EventArgs e) { ThreadPool.QueueUserWorkItem(new WaitCallback(DoWork)); } private void DoWork(object stateInfo) { count++; listBox1.Items.Add(count); if (count == tps) { count = 0; timer1.Stop(); label2.Text = label2.Text + " " + DateTime.Now.ToString("hh:mm:ss.fff"); timer1.Enabled = false; } label3.Text = listBox1.Items.Count.ToString(); }Do you have an idea how I can resolve this issue? Thank you in advance. Regards, Goran
The bad news is that you can't resolve this issue. If you think about it for a little bit, you'll see why. Here's a hint - you need to execute a task several number of times a second and those tasks take a finite amount of time; creating the threads (or switching to them in a threadpool) also takes a period of time - even if you are running on a multi-core machine, there are only a set number of tasks that can be spawned and run in that period of time. By the way, you have a marshalling issue in your code (you may be suppressing it, but it still takes time). Basically, you are interacting with a UI component from a none-UI thread. WinForms is STA, so you should be marshalling the calls back to the UI thread.
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Try System.Timers.Timer[^] which is more accurate than its forms counterpart.
"Don't confuse experts with facts" - Eric_V
Thanks for your answer. I've tried to use System.Timers.Timer and the results a bit better. But, there's one thing I've noticed. Sometimes, the number of items I've added to listbox is greater than number I've entered to text box. For example, when I enter 11 to text box, the number of items in list box is 12. The order is as follows: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 1. I don't understand why 1 again?
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The bad news is that you can't resolve this issue. If you think about it for a little bit, you'll see why. Here's a hint - you need to execute a task several number of times a second and those tasks take a finite amount of time; creating the threads (or switching to them in a threadpool) also takes a period of time - even if you are running on a multi-core machine, there are only a set number of tasks that can be spawned and run in that period of time. By the way, you have a marshalling issue in your code (you may be suppressing it, but it still takes time). Basically, you are interacting with a UI component from a none-UI thread. WinForms is STA, so you should be marshalling the calls back to the UI thread.
Forgive your enemies - it messes with their heads
My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility
Thanks for the answer. Yes. I supposed this couldn't be resolved to be absolutely accurate. But what to do? I need to write the application that should load test WCF RIA service and the results should be confidential.
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Thanks for the answer. Yes. I supposed this couldn't be resolved to be absolutely accurate. But what to do? I need to write the application that should load test WCF RIA service and the results should be confidential.
If you are load testing an application, you need to take a different approach. You should be attempting to target it from multiple machines.
Forgive your enemies - it messes with their heads
My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility
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Hi, I have WindowsForms application where I should execute method n-times in a second. The method should be executed inside of its own separate thread. I use thread pool for that purpose. UI contains text box where I enter the number of times of execution and button, which I click to start processing. I've tried to use System.Windows.Forms.Timer but it works for smaller number of executions (~ up to 100). It works means for example 50 calls can be done in 1 second. When the number of calls is growing they can't be executed in 1 second. They need more and more time. The code looks as follows:
private int count = 0; private int tps; public Form1() { InitializeComponent(); ThreadPool.SetMaxThreads(500, 500); } private void button1\_Click(object sender, EventArgs e) { listBox1.Items.Clear(); timer1.Enabled = true; tps = Int32.Parse(textBox1.Text); timer1.Interval = 1000 / tps; timer1.Start(); label1.Text = "Start time: " + DateTime.Now.ToString("hh:mm:ss.fff"); label2.Text = "End time: "; } private void timer1\_Tick(object sender, EventArgs e) { ThreadPool.QueueUserWorkItem(new WaitCallback(DoWork)); } private void DoWork(object stateInfo) { count++; listBox1.Items.Add(count); if (count == tps) { count = 0; timer1.Stop(); label2.Text = label2.Text + " " + DateTime.Now.ToString("hh:mm:ss.fff"); timer1.Enabled = false; } label3.Text = listBox1.Items.Count.ToString(); }Do you have an idea how I can resolve this issue? Thank you in advance. Regards, Goran
Some comments: 1. this article may enlighten you on some timer characteristics: Timer surprises, and how to avoid them[^] 2. this one could help you in solving cross-thread problems: http://www.perceler.com/articles1.php?art=crossthreads1[^] 3. ThreadPools have their own algorithm for launching and creating threads; e.g. launching ten jobs at pretty much the same time would not necessarily cause ten threads to be used, and that is why it's method is called
QueueUserWorkItem, rather thanExecuteNow. Last time I checked, the ThreadPool, when sufficient work has been queued, would launch new threads at a pace of 2 per second. 4. Load testing a component may not be handled best with equidistant requests; I would consider using a fixed number of real threads (not pooled ones), and give each the job to wait a random time, then issue a request, in a loop-forever style. That way you can simulate an average load of your choice with arbitrary phase between the requests. Furthermore I agree with Pete, when he says having more machines to realistically simulate load would be better. :)Luc Pattyn [My Articles] Nil Volentibus Arduum