Windows SDK: How to get the processor frequency?

Q: How to get the processor(s) frequency?

A: One simple method is by using CallNtPowerInformation.

Example

Code:

---

#include <NTstatus.h>
#define WIN32_NO_STATUS
#include <windows.h>
#include <Powrprof.h>
#include <iostream>

typedef struct _PROCESSOR_POWER_INFORMATION {
  ULONG  Number;
  ULONG  MaxMhz;
  ULONG  CurrentMhz;
  ULONG  MhzLimit;
  ULONG  MaxIdleState;
  ULONG  CurrentIdleState;
} PROCESSOR_POWER_INFORMATION, *PPROCESSOR_POWER_INFORMATION;

#pragma comment(lib, "Powrprof.lib")

int main()
{
  // get the number or processors
  SYSTEM_INFO si = {0};
  ::GetSystemInfo(&si);
  // allocate buffer to get info for each processor
  const int size = si.dwNumberOfProcessors * sizeof(PROCESSOR_POWER_INFORMATION);
  LPBYTE pBuffer = new BYTE[size];

  NTSTATUS status = ::CallNtPowerInformation(ProcessorInformation, NULL, 0, pBuffer, size);
  if(STATUS_SUCCESS == status)
  {
      // list each processor frequency
      PPROCESSOR_POWER_INFORMATION ppi = (PPROCESSOR_POWER_INFORMATION)pBuffer;
      for(DWORD nIndex = 0; nIndex < si.dwNumberOfProcessors; nIndex++)
      {
        std::cout << "Processor #" << ppi->Number << " frequency: "
            << ppi->CurrentMhz << " MHz" << std::endl;
        ppi++;
      }
  }
  else
  {
      std::cout << "CallNtPowerInformation failed. Status: " << status << std::endl;
  }
  delete []pBuffer;
  system("pause");
  return status;
}

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Resources

• MSDN: CallNtPowerInformation function
• MSDN: PROCESSOR_POWER_INFORMATION structure