How to use TProcessInfo #2

I had a few e-mails and comments about using TProcessInfo, so I decided to answer those questions in new blog posts.

Q1: How can we find a module which is running a specific thread, giving a thread ID:

A: First of all, Threads are not assigned to modules, they are assigned to processes. You can find a process which is running the thread, by searching in the list of threads owned by each running process. Here is a sample code:

function FindProcessByThreadID(ID: Cardinal): TProcessItem;
var
  ProcessInfo : TProcessInfo;
  AProcess : TProcessItem;
begin
  Result := nil;
  ProcessInfo := TProcessInfo.Create(nil);
  try
    for AProcess in ProcessInfo.RunningProcesses do
    begin
      if Assigned(AProcess.Threads.FindByID(ID)) then
      begin
        Result := AProcess;
        Exit;
      end;
    end;
  finally
    ProcessInfo.Free;
  end;
end;

FindProcessByThreadID iterates over all running processes, and checks which of them has a thread with the given ID. If a process owns a thread with that ID, it will return that process as a TProcessItem object.

Once you have the process object, you can get more information about the process or the specific thread, or you can kill the process, or suspend the thread. For example:

var
  Process : TProcessItem;
begin
  Process := FindProcessByThreadID(StrToInt(3444));
  if Assigned(Process) then
    ShowMessage(Process.FullPath);
end;

The above code looks for a thread with its ID = 3444, and if it is found, it provides full path of the EXE file for that process.

Q2: How can we get memory consumption for a given process?

A: You can read memory info for a given process using TProcessItem.MemoryInfo. It provides different info about the memory the process is consuming. Here is an example for reading memory info of Google Chrome process while it is running :

var
  ProcessInfo : TProcessInfo;
  AProcess : TProcessItem;
begin
  ProcessInfo := TProcessInfo.Create(nil);
  try
    AProcess := ProcessInfo.RunningProcesses.FindByName('Chrome.exe');
    if Assigned(AProcess) then
      ShowMessage(Format('WorkingSet Size = %d, Peak WorkingSet Size = %d',
                         [AProcess.MemoryInfo.WorkingSetSize,
                          AProcess.MemoryInfo.PeakWorkingSetSize]));
  finally
    ProcessInfo.Free;
  end;
end;

First we search for Chrome.exe process among running processes. Once the process is found, we read its current working set size, and pick working set size through MemoryInfo property, and show them in a message box. The values returned are in Bytes.

Q3: How can we get process base priority class or change it?

A: You can access base priority class for a given process or modify it (added in version 1.3), using TProcessItem.

PriorityClassBase. Be careful, adjusting a base priority class of a given process inappropriately might make other processes unresponsive! Here is a example code:

var
  ProcessInfo : TProcessInfo;
  AProcess : TProcessItem;
begin
  ProcessInfo := TProcessInfo.Create(nil);
  try
    AProcess := ProcessInfo.RunningProcesses.FindByName('firefox.exe');
    if Assigned(AProcess) then
      AProcess.PriorityClassBase := BELOW_NORMAL_PRIORITY_CLASS;
  finally
    ProcessInfo.Free;
  end;
end;

You can also change each priority of  each thread within a process by setting BasePriority property of that TThreadItem instace.

Q4: How can I check if a process is 64-bit?

A: You can check this by reading TProcessItem.Is64Bits property.

Q5: How can I get CPU usage for a given process?

A: You can get CPU usage by reading TProcessItem.CPUUsage property.

I hope these few answers and sample source codes can help you use Process Info. For other examples of using Process Info, please refer to this post: How to use TProcessInfo

If there is any question regarding using Process Info, or anything about Delphi that you think worth being mentioned in Tips & Tricks section of this website, please contact me, and let me know about it.

Have Fun!