I am trying to run a thread off of a form, and every once in a while the thread will raise an event for the form to read. When the form gets the event, the form will place the event into a dataset and display it on a datagrid that is on the form. The problem is that the thread will slowly take over all of the processor time. After about 8 events, the form will not even respond anymore. Here is the guts of my test code
// Class and event for Threa
using System
namespace ThreadTestStuf
public delegate void TestEventHandle r(object sender,int count)
public class TestThread
public event TestEventHandle r TestEvent
public bool stopRunning = false
public TestThread(
{
public void RunningThread()
int xyz = 0
while (!stopRunning)
xyz += 1
Console.WriteLi ne("Count: " + xyz.ToString())
if (xyz % 1000 == 0)
TestEvent(this, xyz)
// Form that call the test threa
// Data set only has (int count) and (string desc) in i
using System
using System.Drawing
using System.Collecti ons
using System.Componen tModel
using System.Windows. Forms
using System.Data
using System.Threadin g
using ThreadTestStuff
namespace ThreadTes
public class ThreadTestForm : System.Windows. Forms.For
private ThreadTest.Test Set testSet1
private System.Windows. Forms.DataGrid TestDG
private System.Windows. Forms.Button StartThreadButt on
private Thread localThread
private TestThread localTestThread
private System.Componen tModel.Containe r components = null
public ThreadTestForm(
InitializeCompo nent()
protected override void Dispose( bool disposing
{
localTestThread .stopRunning = true
localThread.Abo rt()
if( disposing
if (components != null)
components.Disp ose()
base.Dispose( disposing )
private void InitializeCompo nent(
this.testSet1 = new ThreadTest.Test Set()
this.TestDG = new System.Windows. Forms.DataGrid( )
this.StartThrea dButton = new System.Windows. Forms.Button()
((System.Compon entModel.ISuppo rtInitialize)(t his.testSet1)). BeginInit()
((System.Compon entModel.ISuppo rtInitialize)(t his.TestDG)).Be ginInit()
this.SuspendLay out()
//
// testSet
//
this.testSet1.D ataSetName = "TestSet"
this.testSet1.L ocale = new System.Globaliz ation.CultureIn fo("en-US")
//
// TestD
//
this.TestDG.Dat aMember = ""
this.TestDG.Dat aSource = this.testSet1.T estTable
this.TestDG.Hea derForeColor = System.Drawing. SystemColors.Co ntrolText
this.TestDG.Loc ation = new System.Drawing. Point(16, 24)
this.TestDG.Nam e = "TestDG"
this.TestDG.Siz e = new System.Drawing. Size(320, 144)
this.TestDG.Tab Index = 0
//
// StartThreadButt o
//
this.StartThrea dButton.Locatio n = new System.Drawing. Point(224, 184)
this.StartThrea dButton.Name = "StartThreadBut ton"
this.StartThrea dButton.Size = new System.Drawing. Size(120, 32)
this.StartThrea dButton.TabInde x = 1
this.StartThrea dButton.Text = "Start Thread"
this.StartThrea dButton.Click += new System.EventHan dler(this.Start ThreadButton_Cl ick)
//
// ThreadTestFor
//
this.AutoScaleB aseSize = new System.Drawing. Size(5, 13)
this.ClientSize = new System.Drawing. Size(376, 253)
this.Controls.A dd(this.StartTh readButton)
this.Controls.A dd(this.TestDG)
this.Name = "ThreadTestForm "
this.Text = "Thread Test Form"
((System.Compon entModel.ISuppo rtInitialize)(t his.testSet1)). EndInit()
((System.Compon entModel.ISuppo rtInitialize)(t his.TestDG)).En dInit()
this.ResumeLayo ut(false)
#endregio
/// <summary
/// The main entry point for the application
/// </summary
[STAThread
static void Main()
Application.Run (new ThreadTestForm( ))
private void EventHappend(ob ject sender, int count
localThread.Int errupt()
testSet1.TestTa ble.AddTestTabl eRow(count,"Hel lo There")
// MessageBox.Show (localThread.Th readState.ToStr ing())
private void StartThreadButt on_Click(object sender, System.EventArg s e
{
localTestThread = new TestThread();
localTestThread .TestEvent += new TestEventHandle r(this.EventHap pend);
localThread = new Thread(new ThreadStart(loc alTestThread.Ru nningThread));
localThread.Sta rt();
localThread.IsB ackground = true;
}
}
}
Can anyone help?
Thanks,
Dennis Owens
28  1867 
Dennis Owens <an*******@disc ussions.microso ft.com> wrote: I am trying to run a thread off of a form, and every once in a while
the thread will raise an event for the form to read. When the form
gets the event, the form will place the event into a dataset and
display it on a datagrid that is on the form. The problem is that the
thread will slowly take over all of the processor time. After about 8
events, the form will not even respond anymore. Here is the guts of my
test code.
I'm not surprised - you've got 8 threads in a tight loop. That's bound
to take over the processor! However, you've got a few other nasties
going on...
Firstly, you're accessing stopRunning in a non-thread-safe way. You
should either declare it as being volatile, or wrap any access to it in
a lock.
Secondly, you should never update the GUI from a non-UI thread, as you
currently are doing. You should use Control.Invoke to invoke a delegate
on the UI thread.
Thirdly, why are you calling localThread.Int errupt() from your event?
At that time, you're actually running *in* the thread you're trying to
interrupt!
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
The interrrupt was just a wild guess to try and stop it from sucking up all the processor time. I forgot I left it in there. The only line in that method should be the adding of the row in the dataset. As for your second thing, is this what is causing the thread to take over. Well I will lookup Control.Invoke and see if I can figure it out. I still don't see the eight threads, just the form and the test thread
Thanks Dennis Owen
Hi,
stopRunning doesn't need to be declared volatile and it should not be used
with locks.
Native integer assignment is atomic operation as well as native integer
promotion (even so the last doesn't even count).
No compiler would optimize away loading of cycle variable when there is
nontrivial cycle body (like non-inlined method calls inside of cycle).
And you don't need release/acquire semantic for single variable with atomic
assignment.
Using LOCK for accessing it would be unnecessary performance hit if not to
say a mistake.
I suppose that he misinterpreted meaning of Thread.Interrup t, and you are
correct with the rest of your comments.
-Valery.
See my blog at: http://www.harper.no/valery
"Jon Skeet [C# MVP]" <sk***@pobox.co m> wrote in message
news:MP******** *************** *@msnews.micros oft.com... Dennis Owens <an*******@disc ussions.microso ft.com> wrote: I am trying to run a thread off of a form, and every once in a while
the thread will raise an event for the form to read. When the form
gets the event, the form will place the event into a dataset and
display it on a datagrid that is on the form. The problem is that the
thread will slowly take over all of the processor time. After about 8
events, the form will not even respond anymore. Here is the guts of my
test code.
I'm not surprised - you've got 8 threads in a tight loop. That's bound
to take over the processor! However, you've got a few other nasties
going on...
Firstly, you're accessing stopRunning in a non-thread-safe way. You
should either declare it as being volatile, or wrap any access to it in
a lock.
Secondly, you should never update the GUI from a non-UI thread, as you
currently are doing. You should use Control.Invoke to invoke a delegate
on the UI thread.
Thirdly, why are you calling localThread.Int errupt() from your event?
At that time, you're actually running *in* the thread you're trying to
interrupt!
--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
You have tight loop inside your thread method - of course it eats all
processor resources!
And btw, setting thread as background doesn't affect thread
priority/scheduling. it only says that .Net process can terminate even so
there are some background threads still running (I just think that you got
it wrong too)
and do as Jon said to you - use Invoke when you update controls from non-UI
threads.
-Valery
See my blog at: http://www.harper.no/valery
"Dennis Owens" <an*******@disc ussions.microso ft.com> wrote in message
news:00******** *************** ***********@mic rosoft.com... The interrrupt was just a wild guess to try and stop it from sucking up
all the processor time. I forgot I left it in there. The only line in that
method should be the adding of the row in the dataset. As for your second
thing, is this what is causing the thread to take over. Well I will lookup
Control.Invoke and see if I can figure it out. I still don't see the eight
threads, just the form and the test thread?
Thanks Dennis Owens
Ok here is a simple question, how should this simple example be written
Thanks Dennis Owens
btw (for avoiding being misinterpreted) I didn't say that using bool flag as
thread event is good design :-). He should use kernel object like event for
signaling exit.
-Valery.
See my blog at: http://www.harper.no/valery
"Valery Pryamikov" <Va****@nospam. harper.no> wrote in message
news:%2******** **********@TK2M SFTNGP09.phx.gb l... Hi,
stopRunning doesn't need to be declared volatile and it should not be used
with locks.
Native integer assignment is atomic operation as well as native integer
promotion (even so the last doesn't even count).
No compiler would optimize away loading of cycle variable when there is
nontrivial cycle body (like non-inlined method calls inside of cycle).
And you don't need release/acquire semantic for single variable with
atomic assignment.
Using LOCK for accessing it would be unnecessary performance hit if not to
say a mistake.
I suppose that he misinterpreted meaning of Thread.Interrup t, and you are
correct with the rest of your comments.
-Valery.
See my blog at:
http://www.harper.no/valery
"Jon Skeet [C# MVP]" <sk***@pobox.co m> wrote in message
news:MP******** *************** *@msnews.micros oft.com... Dennis Owens <an*******@disc ussions.microso ft.com> wrote: I am trying to run a thread off of a form, and every once in a while
the thread will raise an event for the form to read. When the form
gets the event, the form will place the event into a dataset and
display it on a datagrid that is on the form. The problem is that the
thread will slowly take over all of the processor time. After about 8
events, the form will not even respond anymore. Here is the guts of my
test code.
I'm not surprised - you've got 8 threads in a tight loop. That's bound
to take over the processor! However, you've got a few other nasties
going on...
Firstly, you're accessing stopRunning in a non-thread-safe way. You
should either declare it as being volatile, or wrap any access to it in
a lock.
Secondly, you should never update the GUI from a non-UI thread, as you
currently are doing. You should use Control.Invoke to invoke a delegate
on the UI thread.
Thirdly, why are you calling localThread.Int errupt() from your event?
At that time, you're actually running *in* the thread you're trying to
interrupt!
--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
Valery Pryamikov <Va****@nospam. harper.no> wrote: stopRunning doesn't need to be declared volatile and it should not be used
with locks.
Native integer assignment is atomic operation as well as native integer
promotion (even so the last doesn't even count).
Being atomic has nothing to do with it. The memory model does not
guarantee that the running thread will *ever* see writes from another
thread unless a memory fence is involved.
You can argue about whether or not it'll actually happen, but I prefer
to work from guarantees when it comes to multi-threading - because
sooner or later, some architecture will come along and destroy all
assumptions apart from the guarantees.
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
Dennis Owens <an*******@disc ussions.microso ft.com> wrote: The interrrupt was just a wild guess to try and stop it from sucking
up all the processor time. I forgot I left it in there. The only line
in that method should be the adding of the row in the dataset. As for
your second thing, is this what is causing the thread to take over.
Well I will lookup Control.Invoke and see if I can figure it out. I
still don't see the eight threads, just the form and the test thread?
Sorry, I thought you'd meant there were 8 clicks, not 8 events -
misread. Yup, there'll only be the one extra thread. It will still be
in a tight loop though, which is going to stuff you to some extent
*whatever* you do.
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
Valery Pryamikov <Va****@nospam. harper.no> wrote: btw (for avoiding being misinterpreted) I didn't say that using bool flag as
thread event is good design :-). He should use kernel object like event for
signaling exit.
On the contrary, I'd say using a boolean (but using it properly) is a
perfectly reasonable way of exiting the thread. How would your code
with an event work? It's basically going to end up doing something
*equivalent* to just checking a flag, assuming that the thread wants to
keep doing work until it's told to stop.
Using a boolean is simple (when done right) and allows clean exit
(unlike, say, aborting the thread). Sure, it requires a memory barrier
in order to guarantee that the thread sees the appropriate change in
value, but those are very cheap in the grand scheme of things. What
benefit is there in doing anything else?
--
Jon Skeet - <sk***@pobox.co m> http://www.pobox.com/~skeet
If replying to the group, please do not mail me too This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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