Need help on replacement of NtQuerySystemInformation on Win x64

Hi,

I am struggling to find a replacement of NtQuerySystemInformation call for 64-bit Windows OS, like on Windows Server 2008 (64-bit). Can someone help me getting overall CPU utilization (average) over all CPU cores?

Cheers,
Dean

__

Code:

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#include "StdAfx.h"
#include "CpuMuninNodePlugin.h"

#define SystemBasicInformation 0
#define SystemPerformanceInformation 2
#define SystemTimeInformation 3

#define Li2Double(x) ((double)((x).HighPart) * 4.294967296E9 + (double)((x).LowPart))

// Initialisation
CpuMuninNodePlugin::CpuMuninNodePlugin()
{
  dbIdleTime = 0;
  dbSystemTime = 0;
  liOldIdleTime.QuadPart = 0;
  liOldSystemTime.QuadPart = 0;
  NtQuerySystemInformation = (PROCNTQSI)GetProcAddress(GetModuleHandle(_T("ntdll")), "NtQuerySystemInformation");

  // Setup first call
  CalculateCpuLoad();
}

CpuMuninNodePlugin::~CpuMuninNodePlugin()
{

}

void CpuMuninNodePlugin::CalculateCpuLoad()
{
  if (NtQuerySystemInformation != NULL) {
    LONG status;
    SYSTEM_PERFORMANCE_INFORMATION SysPerfInfo;
    SYSTEM_TIME_INFORMATION SysTimeInfo;
    SYSTEM_BASIC_INFORMATION SysBaseInfo;

    // get number of processors in the system
    status = NtQuerySystemInformation(SystemBasicInformation, &SysBaseInfo, sizeof(SysBaseInfo), NULL);
    if (status != NO_ERROR)
      return;

    // get new system time
    status = NtQuerySystemInformation(SystemTimeInformation, &SysTimeInfo, sizeof(SysTimeInfo), NULL);
    if (status!=NO_ERROR)
      return;

    // get new CPU's idle time
    status = NtQuerySystemInformation(SystemPerformanceInformation, &SysPerfInfo, sizeof(SysPerfInfo), NULL);
    if (status != NO_ERROR)
      return;

    // if it's a first call - skip it
    if (liOldIdleTime.QuadPart != 0)
    {
      // CurrentValue = NewValue - OldValue
      double diffIdleTime = Li2Double(SysPerfInfo.liIdleTime) - Li2Double(liOldIdleTime);
      double diffSystemTime = Li2Double(SysTimeInfo.liKeSystemTime) - Li2Double(liOldSystemTime);

      // CurrentCpuIdle = IdleTime / SystemTime
      dbIdleTime = diffIdleTime / diffSystemTime;

      // CurrentCpuUsage% = 100 - (CurrentCpuIdle * 100) / NumberOfProcessors
      dbIdleTime = 100.0 - dbIdleTime * 100.0 / (double)SysBaseInfo.bKeNumberProcessors + 0.5;
    }

    // store new CPU's idle and system time
    liOldIdleTime = SysPerfInfo.liIdleTime;
    liOldSystemTime = SysTimeInfo.liKeSystemTime;
  }
}

int CpuMuninNodePlugin::GetValues(char *buffer, int len)
{
  CalculateCpuLoad();

  _snprintf(buffer, len,
    "cpu_user.value %f\n"
    //"cpu_system.value %f\n"
    ".\n", this->dbIdleTime);
  return 0;
}

int CpuMuninNodePlugin::GetConfig(char *buffer, int len)
{
  strncpy(buffer,
    "graph_args -l 0 --vertical-label percent --upper-limit 100\n"
    "graph_title Cpu usage\n"
    "graph_category system\n"
    "graph_info This graph shows what the machine uses its cpu for.\n"
    "graph_order cpu_user\n"
    //"graph_order cpu_system cpu_user\n"
    "cpu_user.label user\n"
    "cpu_user.draw AREA\n"
    "cpu_user.info CPU used by user-space applications.\n"
    //"cpu_system.label system\n"
    //"cpu_system.draw STACK\n"
    //"cpu_system.info CPU used by kernel.\n"
    ".\n", len);
  return 0;
}

---

And what is the problem with NtQuerySystemInformation?

Hi,

This API object does not exist in 64bit Windows OS like Windows server 2008. I get a null value. Do you know how I could fix this part of code to get overall average CPU utilisation as a single value from the OS or maybe another engine?

I am new to C++.

Quote:

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Originally Posted by ssddgreg

Hi,

I am struggling to find a replacement of NtQuerySystemInformation call for 64-bit Windows OS, like on Windows Server 2008 (64-bit). Can someone help me getting overall CPU utilization (average) over all CPU cores?

---

Why don't you want to use the way MSDN recommends:

Quote:

---

[NtQuerySystemInformation may be altered or unavailable in future versions of Windows. Applications should use the alternate functions listed in this topic.]
...
SystemBasicInformation
... Use the GetSystemInfo function instead.
...
SystemExceptionInformation
SystemInterruptInformation
SystemLookasideInformation
SystemPerformanceInformation
....
Use the CryptGenRandom function instead.
...
Use GetSystemInfo instead.
...
Use the SLGetWindowsInformation function instead.
...
use GetProcessHandleCount ...
...
Use GetSystemTimes instead
...
Use GetSystemRegistryQuota instead

---

Quote:

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Originally Posted by VictorN

Why don't you want to use the way MSDN recommends:

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I cannot find any substitute for CPU utilisation for the whole machine.

overall CPU usage can be obtained with GetSystemTimes()
CPU load in percent = ((systemtime - idletime) *100) / systemtime

for realtime information there's WMI.