Multithreading – is Delphi 2009 wait chain traversal provided in Windows 7 installation?

According to the "new features of Delphi 2009", there is a new debugger function called "waiting chain traversal" In particular, it said: "a waiting chain traversal function has been added to help you solve thread contention or deadlock problems. This function depends on the tools added to the Windows Vista operating system. It provides the debugger with information about the waiting state of application threads in the form of waiting chain"

Delphi 2009 was released when Windows vista was the current operating system From my experience, most of the features introduced in Vista can also be used in Windows 7 However, in Delphi 2009, I saw this function through Delphi Xe installation (none on Windows 7)

I'm looking for this feature in the threads pane of the debugger

I'm looking for the right place to wait for chain traversal? > Is it a feature that is really only available in Windows Vista, not in Windows 7?

David M provides a good and clear answer, but I still don't get the "waiting chain" column in the threads pane Here are some codes

Main forms:

unit Main;

interface

uses
  Windows,Messages,SysUtils,Variants,Classes,Graphics,Controls,Forms,Dialogs,StdCtrls,SyncObjs,RanThread;

type
  TForm1 = class(TForm)
    List@R_460_2419@1: TList@R_460_2419@;
    Button1: TButton;
    Button2: TButton;
    Label1: TLabel;
    procedure Button2Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    procedure ThreadDone(Sender: TObject);
  end;

var
  Form1: TForm1;
  RanGenThread: TRandomizer;

implementation

uses LoadThread;

{$R *.dfm}

{ TForm1 }

procedure TForm1.ThreadDone(Sender: TObject);
begin
  RanGenThread.Free;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
List@R_460_2419@1.sorted := True;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  Thread: TLoader;
begin
List@R_460_2419@1.Items.Clear;
List@R_460_2419@1.sorted := False;
RanGenThread := TRandomizer.Create(True);
RanGenThread.ArraySize := 1000;
Thread := TLoader.Create(True);
with Thread do
begin
  RanGenThread.WaitThread := Thread;
  FreeOnTerminate := True;
  OnTerminate := ThreadDone;
  WaitForThread := RanGenThread;
  //Use Start in Delphi 2010 or later,where Resume is deprecated
  Resume;
end;
RanGenThread.Resume;
end;

initialization
  Randomize;

end.

TRandomizer：

unit RanThread;

interface

uses
  Classes,Math,SyncObjs;

type
  TRandomizer = class(TThread)
  private
    { Private declarations }
    FArraySize: Integer;
  protected
    procedure Execute; override;
  public
    WaitThread: TThread;
    RandNumbers: array of Integer;
    property ArraySize: Integer read FArraySize write FArraySize;

  end;

implementation

uses Main;

procedure TRandomizer.Execute;
var
  i: Integer;
  LowNum,HighNum: Integer;
  RandNum: Integer;
begin
if FArraySize = 0 then
  begin
    Exit;
  end;
SetLength(RandNumbers,FArraySize);
LowNum := Low(RandNumbers);
HighNum := High(RandNumbers);
//initialize the array
for i := LowNum to HighNum do
  RandNumbers[i] := -1;
// generate the random order
for i := LowNum to HighNum do
  while True do
    begin
      RandNum := RandomRange(LowNum,HighNum + 1);
      if RandNumbers[RandNum] = -1 then
      begin
        RandNumbers[RandNum] := i + 1;
        break;
      end; // if
    end; // while
    WaitThread.WaitFor;
end;

end.

TLoader：

unit LoadThread;

interface

uses
  Classes,RanThread;

type
  TLoader = class(TThread)
  private
    FWaitForThread: TRandomizer;
    procedure UpdateList;
    { Private declarations }
  protected
    procedure Execute; override;
  public
    property WaitForThread: TRandomizer
      read FWaitForThread write FWaitForThread;
  end;

implementation

uses Main;

procedure TLoader.UpdateList;
var
 i: Integer;
begin
for i := Low(FWaitForThread.RandNumbers) to
  High(FWaitForThread.RandNumbers) do
  Form1.List@R_460_2419@1.Items.Add(IntToStr(FWaitForThread.RandNumbers[i]));
end;

procedure TLoader.Execute;
begin
if WaitForThread <> nil then
begin
  FWaitForThread.WaitFor;
  Synchronize(UpDateList)
end;
end;

end.

According to the waiting chain traversal document linked by David M, WTC can be used for the following synchronization objects:

>Alpc > com > key parts > mutual exclusion > SendMessage > waiting for operations on processes and threads

My code waits for a thread, but it is a TThread, not a direct native thread Tonight, I'll modify my code example to deadlock while waiting for a mutex to see if it causes the "wait chain" column to appear in the threads pane

OK Finally, find time for the next test Create an application that occupies a mutex at startup Create a handle that uses OpenMutex to get the Mutex and then call the WaitForsingleObject (handle, INFINITE) worker thread. There is still no waiting chain column in the threads pane

Solution

>Yes Write a program with two thread deadlocks You will see that in the threads pane, the right column (labeled wait chain) displays "waiting for locks held by thread 12345" I'm not quite sure about the exact phrase because there is no deadlock in my current program:) if you don't see it, scroll to the right It's strange if the column doesn't exist - please say it in the comments

Editor: I tried the sample code in Delphi 2010 on Vista machine (I'm not afraid of 2009) I clicked button1 and button2, and then switched to the threads view without pausing the program In the threads pane, there is a waiting chain column that contains the text of two non main threads "blocked waiting threads 11968" or "14416"

This is a screenshot:

If this function works, then this is what you should get in the IDE

When you try this, you get other columns, but not waiting for chain columns? If so, I admit I'm a little confused. I think the next step may be to contact Embarcadero or at least publish it in one of their forums, probably this one I found out what permissions the wait chain function requires, but if you are using a process owned by the current user, you seem to be don't even need se_ DEBUG_ NAME. (I'm not entirely sure this is a valid interpretation of the document, but...)

I don't think your ide runs in odd privilege or XP compatible mode? Editor 4: This is the answer Please refer to Cary's comments below. The shortcut runs in XP compatible mode

Editor 2: I thought I would do a sanity check and look up what their help file said I can't find help online in 2009, but the help in 2010 says "wait chain: (for Windows Vista and 7 only)" Cool Then I looked at the help of Xe and said 'wait chain: (for Windows Vista only)' Very strange.

I suspect this is a document error. It should work on Windows 7, because I also encountered this Delphi 2009 hotfix for wait chain traversal running on Windows 7 Sounds very supportive of me! There is no way to be sure that this feature will be removed from the latest version of windows... Right? Even if they use a version, it is recorded

Editor 3: I asked my colleagues using Windows 7 to try your sample code This is what he got:

On this point, I admit I'm a little confused I can say that the works using rad studio 2010 on Windows 7, as far as I know, should be suitable for you If not, I don't have more suggestions beyond the above vague ideas!