Limit CPU Utilization (LCU) Version 1.52
LCU limits the CPU utilization of any application.
This tool was originally developed to address the problems, coming along with the behaviour of Microsoft Access 97, described in the Microsoft Knowledge Base article Q160819.
Microsoft Access 97 polls its message queues for activity for about the first 30 seconds of idle time. During this time, the application uses 100 percent of CPU resources. Although Microsoft Access only uses CPU resources that are idle, it becomes a problem concerning energy consumption (especially with notebooks) and CPU cooling.
LCU discontinues all processes periodically, which are instances of a given image file.
By adjusting the "DownTime" the CPU utilization can be reduced by about 50%-90% without noticeable loss of performance. When LCU is active, it scans the system periodically for new processes, which have to be treated. So, LCU recognizes new started or terminated processes at runtime.
Although LCU was originally developed for the use with Microsoft Access 97, it can be used to reduce the CPU utilization of any application. Even older Win16 applications can be tamed with LCU. If you want to tame a Win16 application (e.g. Microsoft Access 2.0) you have to enter "ntvdm.exe" as ImageFileName. Here is a short list with applications for which LCU may be helpful.
- Microsoft Access 97 (Image File: msaccess.exe)
- Microsoft Access 95 (Image File: msaccess.exe)
- Microsoft Access 2.0 (Image File: %Windir%\system32\ntvdm.exe)
- Virtual Box (Image File: VirtualBox.exe)
- Alte DOS- und Win16-Anwendungen (Image File: %Windir%\system32\ntvdm.exe)
*** Start LCU ***
Syntax:
LCU ImageFileName Downtime [-s] [-q] [-h]
ImageFileName:
Path and filename of the image file, which processes should be treated.
Downtime:
Downtime for one period in milliseconds. The duration of one period is about Downtime + 10 ms.
The greater the downtime, the lower is the CPU utilization of the treated processes.
The parameter -s (slowdown) is optional. It activates the feature "Slowdown in background".
This feature can also be controlled in the user interface of LCU. If activated, the treated process will be slowed down stronger, if its application window is in background. In this case the downtime is set to 300 ms.
This feature is only available, while maximal one process has to be treated by LCU. If further processes are started, this feature will be deactivated automatically.
The parameter -q (quiet) is optional.
It causes LCU to start as Systray icon. A double-click on this icon activates the application window of LCU.
If the application window will be minimized, it returns to a Systray icon.
The parameter -h (hidden) is optional. It causes LCU to start hidden. In this mode no application window and no systray icon is available.
Example:
LCU "C:\Progam Files\Microsoft Office\Office\msaccess.exe" 20 -s -q
The downtime can be adjusted at runtime. LCU provides the following operational modes:
Throttle = Treated processes work with limited CPU utilization (default)
Suspend = Treated processes are suspended (processes are stopped)
Release = Treated processes are released (LCU takes no effect on treated processes)
In the status window of LCU the following information is shown:
- Path and filename of the treated image file
- ProccessId and number of threads of every treated process
- Actual und average CPU usage in percent for every treated process
The information is refreshed every 3 seconds.
Note: LCU was originally developed for software that was designed for
single processor computers. On multi processor platforms only ihe usage of
the processor (or core) is shown, which is used by the tamed software.
The behavior of LCU in connection with multi processor software has not been
tested so far.
The option "Always on top" causes LCU to show its application window always in foreground.
*** System Requirements ***
Windows 2000 or higher (Windows 9x systems are not supported)
Note: Processes that are executed as administrator on Windows Vista and Windows 7 will only
be recognized by LCU, if it is also executed as adminstrator.
*** Limitations ***
LCU handles up to 64 processes with maximal 512 threads overall.
*** Copyright ***
This software is freeware and can be distributed without any restrictions.
*** Warranty and Liability ***
The software is provided "AS IS" without any kind of warranty.
The author of this software will not be liable for any damages caused by the use of this software.
Any feedback is welcome.
05/15/2010, Mario Hobert
Last modified: 05/15/2010
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