void some_function(){
struct timeval tstart,tend;
while (1){
   gettimeofday (&tstart, NULL);
   ...
   Some computation
   ...
   gettimeofday (&tend, NULL);
   diff = (tend.tv_sec - tstart.tv_sec)*1000000L+(tend.tv_usec - tstart.tv_usec);
   usleep(10000-diff);
   }
}