[강의정리] 로컬변수를 이용한 성능향상1

출처 : 신경준씨 사외교육 http://blog.naver.com/process3/20052147545

[ 전역변수를 이용 ]

 

#include "stdafx.h"
#include <windows.H>
#include <stdio.H>
#include <tchar.H>

volatile int data1;
volatile int data2;

DWORD CALLBACK TestThread1(void* arg)
{

 for (int i = 0; i < 500000000; ++i)       
  data1 = data1 + 1;

  
 return data1;
}

DWORD CALLBACK TestThread2(void* arg)
{  
 for (int i = 0; i < 500000000; ++i)       
  data2 = data2 + 1;  

  
 return data2;
}

int _tmain(int argc, _TCHAR* argv[])
{   
 HANDLE thread[2];   
 
 SetPriorityClass(GetCurrentProcess(), HIGH_PRIORITY_CLASS);    
 
 DWORD startTime = GetTickCount();   
 
 thread[0] = CreateThread(NULL, 0, TestThread1, (LPVOID)0, 0, NULL);   
 thread[1] = CreateThread(NULL, 0, TestThread2, (LPVOID)0, 0, NULL);   
 
 WaitForMultipleObjects(2, thread, TRUE, INFINITE);   
 
 _tprintf(_T("%d\n"), GetTickCount() - startTime);   
 return 0;

}

 

 

[ 지역변수를 이용 ]

 

#include "stdafx.h"
#include <windows.H>
#include <stdio.H>
#include <tchar.H>

//volatile int data1;
//volatile int data2;

DWORD CALLBACK TestThread1(void* arg)
{

 int data1;

 for (int i = 0; i < 500000000; ++i)       
  data1 = data1 + 1;

  
 return data1;
}

DWORD CALLBACK TestThread2(void* arg)
{  

 int data2; 

 for (int i = 0; i < 500000000; ++i)       
  data2 = data2 + 1;  

  
 return data2;
}

int _tmain(int argc, _TCHAR* argv[])
{   
 HANDLE thread[2];   
 
 SetPriorityClass(GetCurrentProcess(), HIGH_PRIORITY_CLASS);    
 
 DWORD startTime = GetTickCount();   
 
 thread[0] = CreateThread(NULL, 0, TestThread1, (LPVOID)0, 0, NULL);   
 thread[1] = CreateThread(NULL, 0, TestThread2, (LPVOID)0, 0, NULL);   
 
 WaitForMultipleObjects(2, thread, TRUE, INFINITE);   
 
 _tprintf(_T("%d\n"), GetTickCount() - startTime);   
 return 0;

}