Linux与Windows控制CPU使用率曲线

前几天无聊，按照《编程之美》第一题写了个控制CPU使用率的程序，把自己的代码贴出来，供以后学习……

效果图如下：

Ubuntu Linux下截图

Windows下截图

其实程序的设计思想很简单，Windows任务管理器中CPU使用率基本上1s刷新一次，而CPU使用率其实就是在1s中CPU忙和闲时间的均值。因此，根据我们想要得到的CPU曲线的特点，我们首先做出忙闲时间的表，CPU根据忙闲时间选择执行或挂起。

代码如下：

#include <windows.h>
#include <stdlib.h>
#include <math.h>

#define COUNT 200

const double SPLIT = 0.01;
const double PI = 3.14159265;
const double SLOPE = 150;
const int INTERVAL = 300;

DWORD WINAPI SineThread(LPVOID Sine)
{
 DWORD busySpan[COUNT];
 DWORD idleSpan[COUNT];
 int half = INTERVAL/2;
 double radian = 0.0;
 DWORD startTime;
 int i;

 for (i=0; i<COUNT; i++)
 {
  busySpan[i] = (DWORD)(half + half*sin(PI*radian));
  idleSpan[i] = (DWORD)(INTERVAL - busySpan[i]);
  radian += SPLIT;
 }
 i = 0;
 while(1)
 {
  i %= COUNT;
  startTime = GetTickCount();
  while((GetTickCount()-startTime) <= busySpan[i])
   ;
  Sleep(idleSpan[i]);
  i++;
 }
 return 0;
}

DWORD WINAPI SawThread(LPVOID Saw)
{
 DWORD busySpan[COUNT];
 DWORD idleSpan[COUNT];
 int half = INTERVAL/2;
 double radian = 0.0;
 DWORD startTime;
 int i;

 for (i=0; i<COUNT; i++)
 {
  busySpan[i] = (DWORD)(SLOPE*radian);
  idleSpan[i] = (DWORD)(INTERVAL - busySpan[i]);
  radian += SPLIT;
 }
 i = 0;
 while(1)
 {
  i %= COUNT;
  startTime = GetTickCount();
  while((GetTickCount()-startTime) <= busySpan[i])
   ;
  Sleep(idleSpan[i]);
  i++;
 }
 return 0;
}

int main()
{
 HANDLE hThread1, hThread2;
 DWORD dwThreadId1, dwThreadId2;

 hThread1 = CreateThread(NULL, 0, SineThread, 0, CREATE_SUSPENDED, &dwThreadId1);
 hThread2 = CreateThread(NULL, 0, SawThread, 0, CREATE_SUSPENDED, &dwThreadId2);
 SetThreadAffinityMask(hThread1, 1);
 SetThreadAffinityMask(hThread2, 2);
 ResumeThread(hThread1);
 ResumeThread(hThread2);
 SuspendThread(GetCurrentThread());
 return 0;
}