Threading: Threads stall, while others run.

[DTeCH]

When the program starts, it checks for the amount of threads the user wants to use to download files with. The threads are then created. When the user chooses a file to download, the threads begin grabbing the file until it's fully downloaded.

The problem is, some threads stall right from the start, & just sit there doing nothing.

The global work variable is Sync-Locked, then quickly released by each instance, & to my eyes, there is nothing wrong.

They are all instances of the same class, & do the exact same thing, so why is it that some run, & others don't?

VB.NET is the programming language. They are looping Background workers.

I would really like to know why some run, & others don't.

btw... they have quick non-blocking sleeps, as well as blocking sleeps to allow others the chance to run (proprietary non-blocking DLL).

So all i'm left to think on is that Microsoft's process queuing has some type of bug going on in there someplace.

Can anyone verify this?

...or is there a way to do multiple looping threads where they're guaranteed to run?

Any help will be awesomely appreciated.

[Christian Binder]

Did you debug the working-method, if this method is called at all?

Can you provide some code?

Is the amount of running (well working) threads always the same or does it differ when you cloae your program and start it again?

[DTeCH]

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Process.GetCurrentProcess.PriorityClass = ProcessPriorityClass.Idle

        Try
            sServer = GetSetting("Program's Name", "Server Settings", "Server").Trim
        Catch ex As Exception
            sServer = ""
        End Try
        Try
            iPort = CInt(Val(GetSetting("Program's Name", "Server Settings", "Port").Trim))
            If iPort = 0 Then
                iPort = 119
            End If
        Catch ex As Exception
            iPort = 119
        End Try
        Try
            bIsSSL = GetSetting("Program's Name", "Server Settings", "SSL").Trim
        Catch ex As Exception
            bIsSSL = False
        End Try
        Try
            UserConnections = CInt(Val(GetSetting("Program's Name", "Server Settings", "Connections").Trim))
            If UserConnections = 0 Then
                UserConnections = 2
            End If
        Catch ex As Exception
            UserConnections = 2
        End Try
        Try
            sUsername = _Decrypt(GetSetting("Program's Name", "Server Settings", "UserName").Trim, GenerateSysKey())
        Catch ex As Exception
            sUsername = ""
        End Try
        Try
            sPassword = _Decrypt(GetSetting("Program's Name", "Server Settings", "Password").Trim, GenerateSysKey())
        Catch ex As Exception
            sPassword = ""
        End Try
        If sServer IsNot "" And sServer IsNot Nothing And UserConnections <> 0 Then
            _BTCount = UserConnections
            xBGThread = New Thread(AddressOf ThreadBeginThreads)
            xBGThread.SetApartmentState(ApartmentState.STA)
            xBGThread.Priority = ThreadPriority.Lowest
            xBGThread.IsBackground = True
            xBGThread.Start()
            bReadyToConnect = True
            GoTo 1
        Else
            If frmSettings.ShowDialog() = DialogResult.OK Then
                If sServer IsNot "" And sServer IsNot Nothing Then
                    If iPort <> 0 Then
                        bReadyToConnect = True
                    End If
                End If
            End If
        End If
        If bReadyToConnect = True Then
            _BTCount = UserConnections
            xBGThread = New Thread(AddressOf ThreadBeginThreads)
            xBGThread.SetApartmentState(ApartmentState.STA)
            xBGThread.Priority = ThreadPriority.Lowest
            xBGThread.IsBackground = True
            xBGThread.Start()
        End If
1:
        Dim EXfileName As String = Nothing
        Try
            If Command() Is Nothing Or Command() = "" Then
      'No Commandline passed in
            Else
  	'Deal with Commandline params
          End If
        Catch ex As Exception
            MsgBox(ex.Message & vbCrLf & vbCrLf & Command().Trim)
        End Try
    End Sub

This is an example of the threads being created:

    Public Sub ThreadBeginThreads()
        Dim _Count As Integer = _BTCount
        DLThreads.Clear() ' Global list(Of Integer)
        For i As Integer = 0 To (_Count - 1)
            DLThreads.Add(0)
            Select Case i
                Case 0
                    BG_Work0.RunWorkerAsync()
                Case 1
                    BG_Work1.RunWorkerAsync()
                Case 2
                    BG_Work2.RunWorkerAsync()
                Case 3
                    BG_Work3.RunWorkerAsync()
                Case 4
                    BG_Work4.RunWorkerAsync()
                Case 5
                    BG_Work5.RunWorkerAsync()
                Case 6
                    BG_Work6.RunWorkerAsync()
                Case 7 ' And so on...
                    BG_Work7.RunWorkerAsync()
            End Select
        Next
        DLThreads.Add(0)
    End Sub

This is an example of the BG_Work0:

    Public WithEvents  _Son0 As TheClassThatDoesTheWork 'Declaration in Form1
    ' And so on...

    Private Sub BG_Work0_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles BG_Work0.DoWork
        _Son0 = New TheClassThatDoesTheWork(0)
    End Sub

This is an example of _Son0 getting fired events from the instance of TheClassThatDoe sTheWork(0):

    Private Sub _Son0_WorkerParent_OnTransfer(ByVal ID As Integer, ByVal _SegFileName As String, ByVal _SegPartNumber As Integer, ByVal _MaxSegParts As Integer, ByVal e As  _TransferEventArgs) Handles _Son0.WorkerParent_OnTransfer
        Try
            ' Deal with the event
        Catch ex As Exception
            ' Deal with Error
        End Try
    End Sub

This is an example of TheClassThatDoe sTheWork(0):

'Imports required

Public Class TheClassThatDoesTheWork

'All the declarations required
'All the events


    Public Property Terminate_ThreadWorker As Boolean
        Get
            Return xTerminateThread
        End Get
        Set(ByVal value As Boolean)
            xTerminateThread = value
        End Set
    End Property

    Public Sub New(ByVal xID As Integer)
        _ID = xID
        _Worker.Timeout = 30
        _Worker.NewsServer = sServer
        _Worker.NewsPort = iPort
        _Worker.User = sUsername
        _Worker.Password = sPassword
        Select Case bIsSSL
            Case True
                _Worker.SSLStartMode = sslImplicit
            Case False
                _Worker.SSLStartMode = sslNone
        End Select
        xThread = New Thread(AddressOf DEngine)
        xThread.SetApartmentState(ApartmentState.STA)
        xThread.Priority = ThreadPriority.Lowest
        xThread.IsBackground = True
        xThread.Start()
    End Sub

    Private Sub DEngine()
        Nap = New TakeNap ' Non-Blocking sleep
        Do Until _IsClosing = True Or xTerminateThread = True
            Nap.Sleep(50) ' or  Thread.Sleep(50)
            If SomeVariable > 0 And SomeOtherVariable = False Then
                Try
                    'Get the file
                Catch ex As Exception
	  'Report error to user, then...
                    GoTo 1
                End Try
                BusyNow = False
                If CurrentFile = "" Then GoTo 1
                GC.Collect()
            ElseIf SomeOtherVariable = True Then
                Do Until SomeOtherVariable = False
                    Nap.Sleep(50) ' or  Thread.Sleep(50)
                Loop
            ElseIf SomeVariable < 1 And SomeOtherVariable = True Then
                ' do stuff
            End If
1:
            If PAUSED_STOPPED = True Then
                BusyNow = False
            End If
            If _Worker.Connected = False Then
                BusyNow = False

                Try
                    _Worker.Connect()
                Catch ex As Exception
	 ' Fire an event
                End Try
            End If
        Loop
    End Sub

    'All required Subs, & Functions

    Protected Overrides Sub Finalize()
        MyBase.Finalize()
    End Sub
End Class

This was posted to C# instead of VB.NET, but it's basically the same theory, at least that's what other C-Sharpers have told me.

Sorry for the mistake though.