linux kernel 中获取代码运行时间

struct timeval tstart, tfinish;
long int  duration1;
long int  duration2;
do_gettimeofday(&tstart);

do somesting();

do_gettimeofday(&tfinish);
duration1 = 1000000*(tfinish.tv_sec - tstart.tv_sec) + tfinish.tv_usec - tstart.tv_usec;
printk("lei_guo:%s==>duration1= %ld  \n",__func__,duration1 );
duration1 = duration1/10000;