浅析Linux下精确控制时间的函数

#include <stdio.h>
#include <unistd.h>
#include <sys/time.h>
#include <asm/msr.h>
long long g_var_llOneSecJiffiesCount = 0;
long long GetCurCpuHopCount()
{
        long long llcurrentcpuhopcount;
        int iaux;
        rdtscpll(llcurrentcpuhopcount,iaux);
        return llcurrentcpuhopcount;
}
int main(int argc, char* argv[])
{
        long long llstartvalue = 0;
        long long llendvalue = 0;
        struct timeval starttm,endtm;
        int iaux = 0;
        gettimeofday(&starttm,NULL);
        rdtscpll(llstartvalue,iaux);
        sleep(3);
        rdtscpll(llendvalue,iaux);
        gettimeofday(&endtm,NULL);
        g_var_llOneSecJiffiesCount = ((llendvalue-llstartvalue)*1000000/(endtm.tv_sec*1000000-starttm.tv_sec*1000000+endt
m.tv_usec-starttm.tv_usec));//使用心跳来代替妙
        long long begin_time = GetCurCpuHopCount();
        sleep(100);//该处可以测试一些功能
        long long end_time = GetCurCpuHopCount();
        long long use_time = (end_time - begin_time) * 1000000 / g_var_llOneSecJiffiesCount;
        printf("测试一个功能 use time(us): %lld\n",use_time);
        return 0;
}