ProSysLib: Dissecting the Process

#include "StdAfx.h"
#include "ProcessorUsage.h"

DWORD CProcessorUsage::s_TickMark = 0;
__int64  CProcessorUsage::s_time = 0;
__int64 CProcessorUsage::s_idleTime = 0;
__int64 CProcessorUsage::s_kernelTime = 0;
__int64 CProcessorUsage::s_userTime = 0;
__int64 CProcessorUsage::s_kernelTimeProcess = 0;
__int64 CProcessorUsage::s_userTimeProcess = 0;
int CProcessorUsage::s_count = 0;
int CProcessorUsage::s_index = 0;
int CProcessorUsage::s_lastCpu = 0;
int CProcessorUsage::s_cpu[5] = {0, 0, 0, 0, 0};
int CProcessorUsage::s_cpuProcess[5] = {0, 0, 0, 0, 0};

CProcessorUsage::CProcessorUsage()
{
	::InitializeCriticalSection(&m_cs);

	s_pfnNtQuerySystemInformation = NULL;
	s_pfnGetSystemTimes = NULL;

	m_pInfo = NULL;
	m_uInfoLength = sizeof(PROC_PERF_INFO);

	HMODULE hModule  = ::GetModuleHandle(_T("kernel32.dll"));
	if(hModule)
		s_pfnGetSystemTimes = (pfnGetSystemTimes)::GetProcAddress(hModule, "GetSystemTimes");

	if(!s_pfnGetSystemTimes)
	{
		hModule = ::GetModuleHandle(_T("ntdll.dll"));
		if(hModule)
		{
			s_pfnNtQuerySystemInformation = (pfnNtQuerySystemInformation)::GetProcAddress(hModule, "NtQuerySystemInformation");
			if(s_pfnNtQuerySystemInformation)
			{
				PROC_PERF_INFO tmp;
				s_pfnNtQuerySystemInformation(8, &tmp, m_uInfoLength, &m_uInfoLength);
				m_pInfo = new PROC_PERF_INFO[m_uInfoLength / sizeof(PROC_PERF_INFO)];
			}
		}
	}
	s_TickMark = ::GetTickCount();
}

CProcessorUsage::~CProcessorUsage()
{
	if(m_pInfo)
		delete m_pInfo;

    ::DeleteCriticalSection(&m_cs);
}

void CProcessorUsage::GetSysTimes(__int64 & idleTime, __int64 & kernelTime, __int64 & userTime)
{
	if(s_pfnGetSystemTimes)
		s_pfnGetSystemTimes((LPFILETIME)&idleTime, (LPFILETIME)&kernelTime, (LPFILETIME)&userTime);
	else
	{
		idleTime = 0;
		kernelTime = 0;
		userTime = 0;
		if(s_pfnNtQuerySystemInformation && m_uInfoLength && !s_pfnNtQuerySystemInformation(0x08, m_pInfo, m_uInfoLength, &m_uInfoLength))
		{
			// NtQuerySystemInformation returns information for all
			// CPU cores in the system, so we take the average here:
			int nCores = m_uInfoLength / sizeof(PROC_PERF_INFO);
			for(int i = 0;i < nCores;i ++)
			{
				idleTime += m_pInfo[i].IdleTime.QuadPart;
				kernelTime += m_pInfo[i].KernelTime.QuadPart;
				userTime += m_pInfo[i].UserTime.QuadPart;
			}
			idleTime /= nCores;
			kernelTime /= nCores;
			userTime /= nCores;
		}
	}
}

short CProcessorUsage::GetUsage()
{
    __int64 sTime;
    int sLastCpu;

	CCritSecLock cs(m_cs);
	sTime = s_time;
	sLastCpu = s_lastCpu;

    if(((::GetTickCount() - s_TickMark) & 0x7FFFFFFF) <= 200)
		return sLastCpu;

	__int64 time;
	__int64 idleTime;
	__int64 kernelTime;
	__int64 userTime;
	__int64 kernelTimeProcess;
	__int64 userTimeProcess;

	::GetSystemTimeAsFileTime((LPFILETIME)&time);

    if(!sTime)
    {
		GetSysTimes(idleTime, kernelTime, userTime);
		FILETIME createTime;
		FILETIME exitTime;
		::GetProcessTimes(::GetCurrentProcess(), &createTime, &exitTime, (LPFILETIME)&kernelTimeProcess, (LPFILETIME)&userTimeProcess);

		s_time = time;
		s_idleTime = idleTime;
		s_kernelTime = kernelTime;
		s_userTime = userTime;
		s_kernelTimeProcess = kernelTimeProcess;
		s_userTimeProcess = userTimeProcess;
		s_lastCpu = 0;
		s_TickMark = ::GetTickCount();
		return 0;
	}

    __int64 div = (time - sTime);

	GetSysTimes(idleTime, kernelTime, userTime);

	FILETIME createTime;
	FILETIME exitTime;
	::GetProcessTimes(::GetCurrentProcess(), &createTime, &exitTime, (LPFILETIME)&kernelTimeProcess, (LPFILETIME)&userTimeProcess);

    int cpu;
    int cpuProcess;

     __int64 usr = userTime   - s_userTime;
     __int64 ker = kernelTime - s_kernelTime;
     __int64 idl = idleTime   - s_idleTime;
     __int64 sys = (usr + ker);

	if(sys)
		cpu = int((sys - idl) * 100 / sys); // System Idle take 100 % of cpu;
	else
		cpu = 0;

	cpuProcess = int((((userTimeProcess - s_userTimeProcess) + (kernelTimeProcess - s_kernelTimeProcess)) * 100 ) / div);

	s_time = time;
	s_idleTime = idleTime;
	s_kernelTime = kernelTime;
	s_userTime = userTime;
	s_kernelTimeProcess = kernelTimeProcess;
	s_userTimeProcess = userTimeProcess;
	s_cpu[(s_index ++) %5] = cpu;
	s_cpuProcess[(s_index++) %5] = cpuProcess;
	s_count ++;

	if(s_count > 5)
		s_count = 5;

	cpu = 0;
	int i;
	for(i = 0; i < s_count; i++ )
		cpu += s_cpu[i];
     
	cpuProcess = 0;
	for(i = 0; i < s_count; i++ )
		cpuProcess += s_cpuProcess[i];

	cpu /= s_count;
	cpuProcess /= s_count;   
	s_lastCpu = cpu;
	sLastCpu = s_lastCpu;
	s_TickMark = ::GetTickCount();
    return sLastCpu;
}