Task Manager process CPU usage?

Peter Sjostrom

Hi, I know how to use the PSI.DLL (was it?) for checking a process' memory usage etc. But how can I get information about each process' CPU usage? I want to include a CPU usage bar in my software to display how much CPU that software is using. Hints anyone?

Bill Wilson

WMI provides that information. I don't remember the specific profider. something like WIN32_Process. There are some examples of exactly what you are trying to do. I saw them while looking for some other WMI code. Just do some searches on google, code guru etc. You'll find them. Hope this helps, Bill

Peter Sjostrom

I managed to find PDH.DLL which uses either WMI or Registry data. I can get CPU usage from here, MSDN also contains docs on this DLL. Only problem now is I can't understand how to get process CPU usage, which functions, do I use Counters etc, how do I set them up? An example would be perfect. :-)

Bill Wilson

I don't know which method your asking about... With WMI, get all instances of Win_32_Processor provider and query the LoadPercentage. This will return an average over 1 second. Here is the class I ended up using in my project utilizing the PDH.dll. I create an instance of the class for each cpu on the system, query each and take an average, when I want to know the answer. Class definition:

#ifndef __CPUUSAGE_CLASS__
#define __CPUUSAGE_CLASS__
#include

class CCPUUsage {
public:
CCPUUsage();
~CCPUUsage();
#pragma message("CCPUUsage")
BOOL Init(LONG nMinTicksBetweenSamples = 1000, int iProcessor = 0);

int GetUsage(PBOOL pfNewSample = NULL);

private:
HQUERY m_hQuery;
HCOUNTER m_hCounter;
int m_nMinTicksBetweenSamples;
DWORD m_msLastTick;
int m_nLastSampledCPUUsage;
};

#endif // __CPUUSAGE_CLASS__

Class implementation: CCPUUsage::CCPUUsage() { } CCPUUsage::~CCPUUsage() { PdhCloseQuery(m_hQuery); } BOOL CCPUUsage::Init(LONG nMinTicksBetweenSamples, int iProcessor) { m_nMinTicksBetweenSamples = nMinTicksBetweenSamples; m_msLastTick = 0; // m_msLastTick = GetTickCount(); PDH_STATUS pdhs = PdhOpenQuery(NULL, 0, &m_hQuery); CString csPath; csPath.Format("\\Processor(%d)\\%% processor time", iProcessor); pdhs = PdhAddCounter(m_hQuery, TEXT(csPath), 0, &m_hCounter); CString strDiag; strDiag.Format("CCPUUsage::Init, pdhs = %x, Processor = %d",pdhs,iProcessor); TRACEX(strDiag); m_nLastSampledCPUUsage = 0; return (pdhs == 0); } int CCPUUsage::GetUsage(PBOOL pfNewSample ) { BOOL fNewSample; if (pfNewSample == NULL) pfNewSample = &fNewSample; *pfNewSample = FALSE; DWORD msCurrentTick = GetTickCount(); DWORD msLastTick = m_msLastTick; if (msCurrentTick < msLastTick) { // Wrap around, always sample *pfNewSample = TRUE; } else { if ((msLastTick + m_nMinTicksBetweenSamples) < msCurrentTick) { // It's been long since the last sample, get a new sample *pfNewSample = TRUE; } } CString szdiag; if (*pfNewSample) { if ((DWORD) InterlockedExchange((PLONG) &m_msLastTick, msCurrentTick) == msLastTick) { PdhCollectQueryData(m_hQuery); PDH_FMT_COUNTERVALUE pdhfcv; PDH_STATUS stat = PdhGetFormattedCounterValue(m_hCounter, PDH_FMT_LONG, NULL, &pdhfcv); szdiag.Format("GetStatus::PdhGetFormattedCounterValue return

Peter Sjostrom

Well, thanks, it helps to get started on CPU Usage, but it's not what I want. What I want is to measure the CPU Usage for my specific process. I want to know how much CPU my own software is taking, the software that this code is going to go into. I want to know if my software starts to grab 90+ % of the CPU, if it does it's an error situation and action needs to be taken. Task Manager can obviously do it, but I am unable to find out how to do. I'm reading the PDH docs on MSDN, but it's a bit over my head and I thought someone had done it, or maybe the Task Manager code is available somewhere?

Bill Wilson

Here's the WMI code I used for Overall CPU usage. I believe, that by changing the query to use a different provider, you can get the info you want. I've seen an example that enumerates processes and gets info about them. In any case this class is hard won knowledge and may help.

// SysInfo.h : Declaration of the CSysInfo

#ifndef __SYSINFO_H_
#define __SYSINFO_H_

#include "resource.h" // main symbols
#include
#include

/////////////////////////////////////////////////////////////////////////////
// CSysInfo
class ATL_NO_VTABLE CSysInfo :
public CComObjectRootEx,
public IDispatchImpl,
public CComControl,
public IPersistStreamInitImpl,
public IOleControlImpl,
public IOleObjectImpl,
public IOleInPlaceActiveObjectImpl,
public IViewObjectExImpl,
public IOleInPlaceObjectWindowlessImpl,
public ISupportErrorInfo,
public CComCoClass
{
public:
CSysInfo()
{
m_pUnkMarshaler = NULL;

}


~CSysInfo();

DECLARE_GET_CONTROLLING_UNKNOWN()
DECLARE_REGISTRY_RESOURCEID(IDR_SYSINFO)

DECLARE_PROTECT_FINAL_CONSTRUCT()

BEGIN_COM_MAP(CSysInfo)
COM_INTERFACE_ENTRY(ISysInfo)
COM_INTERFACE_ENTRY(IDispatch)
COM_INTERFACE_ENTRY(IViewObjectEx)
COM_INTERFACE_ENTRY(IViewObject2)
COM_INTERFACE_ENTRY(IViewObject)
COM_INTERFACE_ENTRY(IOleInPlaceObjectWindowless)
COM_INTERFACE_ENTRY(IOleInPlaceObject)
COM_INTERFACE_ENTRY2(IOleWindow, IOleInPlaceObjectWindowless)
COM_INTERFACE_ENTRY(IOleInPlaceActiveObject)
COM_INTERFACE_ENTRY(IOleControl)
COM_INTERFACE_ENTRY(IOleObject)
COM_INTERFACE_ENTRY(IPersistStreamInit)
COM_INTERFACE_ENTRY2(IPersist, IPersistStreamInit)
COM_INTERFACE_ENTRY(ISupportErrorInfo)
COM_INTERFACE_ENTRY_AGGREGATE(IID_IMarshal, m_pUnkMarshaler.p)
END_COM_MAP()

BEGIN_PROP_MAP(CSysInfo)
PROP_DATA_ENTRY("_cx", m_sizeExtent.cx, VT_UI4)
PROP_DATA_ENTRY("_cy", m_sizeExtent.cy, VT_UI4)
// Example entries
// PROP_ENTRY("Property Description", dispid, clsid)
// PROP_PAGE(CLSID_StockColorPage)
END_PROP_MAP()

BEGIN_MSG_MAP(CSysInfo)
CHAIN_MSG_MAP(CComControl)
DEFAULT_REFLECTION_HANDLER()
END_MSG_MAP()
// Handler prototypes:
// LRESULT MessageHandler(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled);
// LRESULT CommandHandler(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled);
// LRESULT NotifyHandler(int id

Peter Sjostrom

Ok, some guesswork and trial and error... First, as with another article I found on the net, the processor time parameter is Windows language dependant: csPath.Format("\\Processor(%d)\\%% processor time", iProcessor); changes into: csPath.Format("\\Processor(%d)\\%% processortid", iProcessor); ...to work on my Swedish Windows. I don't know how to find this for any language yet. To find the CPU Usage for a specific process use: csPath.Format("\\Process(%s)\\%% processortid", sProcess); for example: csPath.Format("\\Process(iexplore)\\%% processortid"); for Internet Explorer CPU usage. This does what I want now, except for that language dependency which I must solve now... (anyone know?)

Peter Sjostrom

Oops, thanks a lot! I will digest this in upcoming days :omg: