Questions about clock_gettime and friends

[Woodchuck]

I.  The system call clock_getres(2) and clock_gettime(2) show strange
results.

Consider this small program and its output on OpenBSD 5.0, amd64:

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

main()
{
        struct timespec tp;
        int             i;

        clock_getres(CLOCK_REALTIME, &tp);
        printf("Resolution:  %lu %lu\n", tp.tv_sec, tp.tv_nsec);
        for (i = 0; i < 10; i++) {
                clock_gettime(CLOCK_REALTIME, &tp);
                printf("Performance: %lu %lu\n", tp.tv_sec, tp.tv_nsec);
        }
        return 0;
}

Resolution:  0           10000000
Performance: 1331012858 566149475
Performance: 1331012858 566158834
Performance: 1331012858 566164422
Performance: 1331012858 566169031
Performance: 1331012858 566173152
Performance: 1331012858 566177202
Performance: 1331012858 566181253
Performance: 1331012858 566189075
Performance: 1331012858 566195570
Performance: 1331012858 566219945

Surely the clock is resolving better than 10 milliseconds?

II.  The man page asserts:

"clock_id can be one of four values: CLOCK_REALTIME for time that
increments as a wall clock should, CLOCK_VIRTUAL for time ..."

How "should" a wall clock increment?  Differently from CLOCK_MONOTONIC?

Thank you for your kind attention,

Dave