Re: Memory Problem

From: Daniel Moth (dmoth74_at_hotmail.com)
Date: 01/09/05 

Date: Sun, 9 Jan 2005 16:20:20 -0000

Sorry I am not observing the same results as you. I am testing with a
release version and while not connected to VS, I assume you are doing the
same. The before/after numbers are the same throughout.

On what device are you trying this and is it replicatable in the emulator?

In any case, make sure you have the latest SP3 installed:
http://wiki.opennetcf.org/ow.asp?CompactFrameworkFAQ%2FDeterminingVersion

For more info on GC metrics for your app try the performance counters
(follow the two links in the first paragraph):
http://www.danielmoth.com/Blog/2004/08/performance-statistics-for-netcf-apps.html

If you are still having troubles I suggest updating your sample as the
current one does not have the GlobalMemoryStatus calls you mentioned (and I
don't know what else).

Cheers
Daniel 

--
http://www.danielmoth.com/Blog/
"Mike Mc" <MikeMc@discussions.microsoft.com> wrote in message 
news:BCD6D944-31E0-489F-9010-52BA2B7D43EF@microsoft.com...
> Good question and thanks for the reply -- I should have included more 
> info.
> I am using a 64MB device -- and have been pinvoking GlobalMemoryStatusCE 
> for
> memory info.  Here are some stats on the sample program with my first 
> message:
> * Available determined from AvailablePhysical returned from
> GlobalMemoryStatusCE
> ** % Load from Memory Load returned from GlobalMemoryStatusCE
>
> Before first run:  ~36MB Available, 17% Load
> After first allocation of array: ~31MB Avaialable, 29% Load
> 2nd allocation: ~26MB Available, 41% Load
>
> Each time I see the 5MB array allocation reflected properly.
> After the third -- I don't get an error (in my sample program below) and 
> it
> just repeats the 2nd allocation stats.  My guess is the the garbage 
> collector
> is freeing up memory at this point -- but why does it not go back to the
> ~36MB before the first run?  Net, net -- I believe I have plenty of 
> memory -- 
> the real question is --- why are my previous memory allocations not 
> freeing
> up?  Any thoughts?
>
>
> "Daniel Moth" wrote:
>
>> >            ReDim baConv(5000000)
>> The obvious question: Is that much memory (>4.5MB) available on the 
>> target?
>>
>> E.g. try in the WinCE emulator and in Settings>ControlPanel->System under
>> the Memory tab configure the available Program Memory and you can get the
>> same results (or not if you move it far to the left)
>>
>> Programmatically try calling GlobalMemoryStatus to see how much memory is
>> free
>>
>> Cheers
>> Daniel
>> --
>> http://www.danielmoth.com/Blog/
>>
>>
>> "Mike Mc" <MikeMc@discussions.microsoft.com> wrote in message
>> news:104EF3DA-5A7F-4608-A103-1885499456E3@microsoft.com...
>> >I am using VS 2003 (VB.Net) on a PPC2003 SP2 device.
>> >
>> > My main program is having memory problems encrypting large byte arrays
>> > that
>> > are passed to/from a .Net webservice.  When I create a 2nd byte array 
>> > (for
>> > the conversion) the memory is not freed up.  Since we receive many of
>> > these
>> > arrays, I eventually get an OutofMemoryException and the 
>> > gc.GetTotalMemory
>> > call shows I am increasing the memory by the expected amount.  After
>> > researching and playing with the garbage collector (gc.collect), my
>> > assumption is that somehow my byte array is still in scope (though I 
>> > don't
>> > understand how).  I have created a very small program to reproduce the
>> > problem -- any help from this community would be greatly appreciated. 
>> > The
>> > program has a button that creates a new 5MB array and two textboxes 
>> > that
>> > show
>> > the gc.GetTotalMemory  before and after the creation.  Here is the 
>> > code:
>> > _________
>> >
>> > Imports testmemory.Class1
>> >
>> > Public Class Form1
>> >    Inherits System.Windows.Forms.Form
>> >    Friend WithEvents Button1 As System.Windows.Forms.Button
>> >    Friend WithEvents MainMenu1 As System.Windows.Forms.MainMenu
>> >
>> > #Region " Windows Form Designer generated code "
>> >
>> >    Public Sub New()
>> >        MyBase.New()
>> >
>> >        'This call is required by the Windows Form Designer.
>> >        InitializeComponent()
>> >
>> >        'Add any initialization after the InitializeComponent() call
>> >
>> >    End Sub
>> >
>> >    'Form overrides dispose to clean up the component list.
>> >    Protected Overloads Overrides Sub Dispose(ByVal disposing As 
>> > Boolean)
>> >        MyBase.Dispose(disposing)
>> >    End Sub
>> >
>> >    'NOTE: The following procedure is required by the Windows Form 
>> > Designer
>> >    'It can be modified using the Windows Form Designer.
>> >    'Do not modify it using the code editor.
>> >    Friend WithEvents Label1 As System.Windows.Forms.Label
>> >    Friend WithEvents Label2 As System.Windows.Forms.Label
>> >    Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
>> >    Friend WithEvents TextBox2 As System.Windows.Forms.TextBox
>> >    Friend WithEvents Button2 As System.Windows.Forms.Button
>> >    Private Sub InitializeComponent()
>> >        Me.MainMenu1 = New System.Windows.Forms.MainMenu
>> >        Me.Button1 = New System.Windows.Forms.Button
>> >        Me.Label1 = New System.Windows.Forms.Label
>> >        Me.Label2 = New System.Windows.Forms.Label
>> >        Me.TextBox1 = New System.Windows.Forms.TextBox
>> >        Me.TextBox2 = New System.Windows.Forms.TextBox
>> >        Me.Button2 = New System.Windows.Forms.Button
>> >        '
>> >        'Button1
>> >        '
>> >        Me.Button1.Location = New System.Drawing.Point(16, 192)
>> >        Me.Button1.Size = New System.Drawing.Size(64, 24)
>> >        Me.Button1.Text = "run test"
>> >        '
>> >        'Label1
>> >        '
>> >        Me.Label1.Location = New System.Drawing.Point(24, 32)
>> >        Me.Label1.Size = New System.Drawing.Size(64, 24)
>> >        Me.Label1.Text = "Before "
>> >        '
>> >        'Label2
>> >        '
>> >        Me.Label2.Location = New System.Drawing.Point(24, 72)
>> >        Me.Label2.Size = New System.Drawing.Size(56, 24)
>> >        Me.Label2.Text = "After"
>> >        '
>> >        'TextBox1
>> >        '
>> >        Me.TextBox1.Location = New System.Drawing.Point(88, 32)
>> >        Me.TextBox1.Size = New System.Drawing.Size(104, 22)
>> >        Me.TextBox1.Text = ""
>> >        '
>> >        'TextBox2
>> >        '
>> >        Me.TextBox2.Location = New System.Drawing.Point(88, 72)
>> >        Me.TextBox2.Size = New System.Drawing.Size(104, 22)
>> >        Me.TextBox2.Text = ""
>> >        '
>> >        'Button2
>> >        '
>> >        Me.Button2.Location = New System.Drawing.Point(80, 240)
>> >        Me.Button2.Size = New System.Drawing.Size(64, 24)
>> >        Me.Button2.Text = "End"
>> >        '
>> >        'Form1
>> >        '
>> >        Me.Controls.Add(Me.Button2)
>> >        Me.Controls.Add(Me.TextBox2)
>> >        Me.Controls.Add(Me.TextBox1)
>> >        Me.Controls.Add(Me.Label2)
>> >        Me.Controls.Add(Me.Label1)
>> >        Me.Controls.Add(Me.Button1)
>> >        Me.Menu = Me.MainMenu1
>> >        Me.Text = "Form1"
>> >
>> >    End Sub
>> >
>> > #End Region
>> >
>> >    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
>> > System.EventArgs) Handles MyBase.Load
>> >
>> >    End Sub
>> >
>> >    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
>> > System.EventArgs) Handles Button1.Click
>> >
>> >        Me.TextBox1.Text = ""
>> >        Me.TextBox2.Text = ""
>> >        'run memory test
>> >        Me.TextBox1.Text = System.GC.GetTotalMemory(False).ToString
>> >        BeginTest()
>> >        Me.TextBox2.Text = System.GC.GetTotalMemory(False).ToString
>> >
>> >    End Sub
>> >
>> >    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As
>> > System.EventArgs) Handles Button2.Click
>> >        Me.Close()
>> >    End Sub
>> > End Class
>> >
>> >
>> > Public Class Class1
>> >
>> >    Friend Shared Sub BeginTest()
>> >        'Call routine to allocate memory
>> >
>> >        Try
>> >            Dim baTest() As Byte = New Byte() {1}
>> >
>> >        Callfunct(baTest)
>> >
>> >        Catch ex As OutOfMemoryException
>> >            MessageBox.Show("BeginTest: " & ex.ToString)
>> >
>> >        Catch ex As Exception
>> >            MessageBox.Show("BeginTest: " & ex.ToString)
>> >        End Try
>> >
>> >
>> >    End Sub
>> >
>> >    Friend Shared Function Callfunct(ByVal batest As Byte()) As Byte()
>> >
>> >        Try
>> >            Dim baConv() As Byte
>> >
>> >            ReDim baConv(5000000)
>> >
>> >        Catch ex As OutOfMemoryException
>> >            MessageBox.Show("Callfunct: " & ex.ToString)
>> >
>> >        Catch ex As Exception
>> >            MessageBox.Show("Callfunct: " & ex.ToString)
>> >        End Try
>> >
>> >        Return (batest)
>> >    End Function
>> > End Class
>> > ____
>> >
>> > Thanks again for your help!
>> > Mike
>>
>>
>>