Imported from: renren.
It is said that this is a problem from interview of Microsoft. Write a program, which makes the CPU usage curve in Windows Task Manager shows a Sin function.
The program below is written in java:
public class sincpu {
private static final int cycle=1024,tick = 256;
public static void main (String[] args) throws InterruptedException {
for(int i = 0;;i++){
work(calcNextSleep(i % cycle));
sleep(tick - calcNextSleep(i % cycle));
}
}
private static long calcNextSleep(long i){
return (int)(Math.sin((double)i * 2 * Math.PI / cycle) * tick + tick) / 2;
}
private static void sleep (long sleepTime) throws InterruptedException
{
if(sleepTime < 2)
Thread.yield();
else
Thread.sleep(sleepTime);
}
private static void work (long period) {
long start = System.currentTimeMillis();
for(;;){
Math.sin(1);
if(System.currentTimeMillis() - start >= period)
break;
}
}
}
Be careful you need to turn off other cores if you have multi-core CPU.
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