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Posted 22 Feb 2007

CPU Load Control

, 22 Feb 2007 CPOL
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Demonstration to control the amount of CPU load used by your computer
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This is a basic MFC program that demonstrates how to retrieve the current CPU load percentage and set it using a high priority thread control loop. I created this project simply because I needed to test another fairly time/buffer critical application and wanted to simulate heavy amounts of CPU load and/or a slower computer. By using this app, you can successfully "steal" away certain amounts of processor instructions to emulate slower or more heavily loaded machines.

It only fully works on single core systems. I personally have a dual core machine, and therefore the one thread that runs in this program can never utilize more than 50% of the "Total Processor Load." I tried launching multiple threads that would hopefully use both cores, but it didn't work - I'm guessing you would have to somehow instruct a 2nd thread to use your second core. Anyway, it wasn't worth it for me to implement, so if anyone wants to add full support for multi-core machines, please post how it's done to others.

Included is a project built using VS 2005. The code is very simple and could be easily added to another project. To retrieve the CPU load percentage, you must include the dependency pdh.lib in your Project->Linker settings.


  • 22nd February, 2007: Initial post


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


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Comments and Discussions

Questiongood Pin
bleachli9-Nov-11 6:13
memberbleachli9-Nov-11 6:13 
GeneralXP is showing two processors Pin
Lokanatha Reddy16-May-07 0:38
memberLokanatha Reddy16-May-07 0:38 
GeneralCPU Load Ported on Visual C++ 6.0 Pin
cristitomi16-Mar-07 0:54
membercristitomi16-Mar-07 0:54 
GeneralNot work in one core PC with Windows2000 Professional Pin
AleksMain27-Feb-07 3:24
memberAleksMain27-Feb-07 3:24 
GeneralRe: Not work in one core PC with Windows2000 Professional Pin
jkhax0r2-Apr-07 7:38
memberjkhax0r2-Apr-07 7:38 
GeneralMulticore Pin
Joergen Sigvardsson22-Feb-07 12:00
memberJoergen Sigvardsson22-Feb-07 12:00 
GeneralRe: Multicore Pin
Vasudevan Deepak Kumar22-Feb-07 19:08
memberVasudevan Deepak Kumar22-Feb-07 19:08 
QuestionRe: Multicore Pin
jkhax0r26-Feb-07 6:16
memberjkhax0r26-Feb-07 6:16 
I tried setting the thread affinity with no luck. Based on the documentation, I seem to have set everything up correctly - the following code detects my two processors, and starts two threads setting up each to run on a different processor, but the load still maxes out at 50%. I setup the load thread to run a while(1){} loop just to make sure and still can't go above 50%. The thread affinity on the process and the thread prior to calling SetThreadAffinity() was set to 0x03, which should have meant they would run on both processors anyway. Maybe I just missed something in the documentation... any suggestions from anyone with more experience w/ multicores?

//Update to get number of processors
DWORD procmask = 0;
DWORD systemmask = 0;

//Get the current processor and system affinity to determine what processors are avaialble
//and which this process can use
HANDLE proc = GetCurrentProcess();
GetProcessAffinityMask(proc, &procmask, &systemmask);

//Count the number of bits set to get the total number of processors on the system
DWORD temp = systemmask;
int numprocs = 0;
while (temp)
if (temp & 0x00000001) //increment count for each bit (processor) set
temp >>= 1;

if (systemmask != procmask)
SetProcessAffinityMask(proc, systemmask);

m_desiredLoad = 0;
HANDLE thread;
DWORD threadaffinity = 0x00000001; //first thread runs on proc1

//now create a thread for each processor and set it to run on a unique proc
for (int i = 0; i < numprocs; ++i)
thread = CreateThread(NULL, 0, &ThreadProc, this, 0, NULL);
DWORD res = SetThreadAffinityMask(thread, threadaffinity);
threadaffinity <<= 1;

AnswerRe: Multicore Pin
Joergen Sigvardsson26-Feb-07 8:29
memberJoergen Sigvardsson26-Feb-07 8:29 
GeneralRe: Multicore Pin
Great-er27-Feb-07 0:54
memberGreat-er27-Feb-07 0:54 
GeneralRe: Multicore Pin
Joergen Sigvardsson27-Feb-07 3:36
memberJoergen Sigvardsson27-Feb-07 3:36 
GeneralRe: Multicore [modified] Pin
Great-er27-Feb-07 9:56
memberGreat-er27-Feb-07 9:56 
GeneralRe: Multicore Pin
jkhax0r28-Feb-07 17:46
memberjkhax0r28-Feb-07 17:46 
QuestionMaybe this would work? Pin
Ivo Beltchev22-Feb-07 11:59
memberIvo Beltchev22-Feb-07 11:59 
AnswerRe: Maybe this would work? Pin
Vasudevan Deepak Kumar22-Feb-07 19:09
memberVasudevan Deepak Kumar22-Feb-07 19:09 
GeneralRe: Maybe this would work? Pin
dongbaek19-Jul-09 23:21
memberdongbaek19-Jul-09 23:21 

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