vivado SDK中如何计算一段程序执行时间？

#include "xtime_l.h" //引用的头文件XTime tend,tcur;u32 tused;XTime_GetTime(&tcur);XTime_GetTime(&tend);tused=((tend-tcur)*1000000)/(COUNTS_PER_SECOND);printf("Time is %d us\r\n",tused);

/* Global Timer is always clocked at half of the CPU frequency */#define COUNTS_PER_SECOND          (XPAR_CPU_CORTEXA9_CORE_CLOCK_FREQ_HZ /2)

#include "xtime_l.h"#include "sleep.h"XTime tend,tcur;int main(){u32 tused;    XTime_GetTime(&tcur);    usleep(13);XTime_GetTime(&tend);   tused=((tend-tcur)*1000000)/(COUNTS_PER_SECOND);   printf("time is %d us\r\n",tused);}