#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>

int
main( int a, char **  b)
{
time_t tick;
struct timeval tv[2];
int prev = 0;
int fwd = 0;
int back = 0;
int max = 0;

 for ( ; ; ) {
     gettimeofday( tv, 0 );
     if (prev)
	 if (tv[0].tv_sec < tv[1].tv_sec ||
	     tv[0].tv_sec == tv[1].tv_sec && tv[0].tv_usec < tv[1].tv_usec){
	     unsigned long delta = ((tv[1].tv_sec - tv[0].tv_sec) * 1000000+
				    (tv[1].tv_usec - tv[0].tv_usec));
	     if (delta > max) max = delta;
	     ++back;
	 } 
	 else
	     ++fwd;
     if (tick != tv[0].tv_sec && tv[0].tv_sec == tv[1].tv_sec + 1) {
	 tick = tv[0].tv_sec;
	 printf( "%.24s: fwd:%d/%d:back max %07lu\n",
		 ctime( &tv[0].tv_sec ), fwd, back, max );
	 fwd = back = 0;
	 max = 0;
     }
     prev = 1;
     tv[1] = tv[0];
 }
}