使用select和chrono对程序进行cpu计时

#include <chrono>

#include <iostream>

using std::chrono::high_resolution_clock;
using std::chrono::microseconds;
using std::chrono::duration_cast;
using namespace std;

void proc_example()
{
    for (int i=0; i<10000000; i++);
}

int main(int argc, char const *argv[])
{
    high_resolution_clock::time_point t = chrono::high_resolution_clock::now();
    const long busyTime =100;
    long startTime =0 ;
    struct timeval tv;
    tv.tv_sec = 0;
    tv.tv_usec = 1000 * busyTime;
    int c = 1;
    int d = 0;
    while(true)
    {
	// cout<<"running"<<endl;
	t = high_resolution_clock::now();
	proc_example();
	tv.tv_usec = 1000000 - duration_cast<microseconds>(high_resolution_clock::now() - t).count();
	select(0, NULL, NULL, NULL, &tv);
	c++;
	if(c == 60)
	{
	    d++;
	    printf("%d min\n", d);
	    c = 0;
	}
    }
    return 0;
}