Change Windows Service Priority

Question

I have a windows service that needs to run with High Priority.
At the end of the day I want to use this script to modify the priority after service startup:

Const HIGH = 256

strComputer = "."
strProcess = "BntCapi2.exe"

Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
Set colProcesses = objWMIService.ExecQuery _
    ("Select * from Win32_Process Where Name = '" & strProcess & "'")

For Each objProcess in colProcesses
    objProcess.SetPriority(HIGH)
Next

But currently I am not able to change the priority, even with the taskmanger. The taskmananger throws an "Access Denied" error, but I am logged on as administrator and I changed the user account of the service to administrator, too.

I still get the "access denied" message when trying to change the priority. Any ideas what permission I need to do that?

Answer 1

I found a way to do this in this blog: http://akshayjain.org/blog/2008/08/hack-unable-to-change-priority-in-task-manager/

If I run this command

ntsd -c qd taskmgr.exe

the taskmanager starts with system privileges and I am able to change the process priority. That means that my wsh script can do this, too. I created a batch file

@ECHO OFF
ntsd -c qd cscript.exe set_service_priority.vbs

and now the process priority get's modified, like I wanted.

Initially I couldn't change process priority because the service ran under the system account. The strange thing is that, even after changing the service user to administrator (that's me ;) I got the "access denied" message. But with this trick that works like a charm.

Answer 2

You might need to add the following to the top of your script:

Set objLoc = createobject("wbemscripting.swbemlocator")
objLoc.Security_.privileges.addasstring "sedebugprivilege", true 

Although.. I wouldn't want to use anything above 128.. (256 = Realtime)

Full list here: http://msdn.microsoft.com/en-us/library/aa393587.aspx