Whichever timer hardware your system is using (you can see with 'sysctl kern.timecounter') seems a bit on the slow side, my 1200MHz X40 runs your test program in 2.9s.
$ sysctl kern.timecounter kern.timecounter.tick=1 kern.timecounter.timestepwarnings=0 kern.timecounter.hardware=ICHPM kern.timecounter.choice=i8254(0) ICHPM(1000) dummy(-1000000) Have you compared bsd with bsd.mp? We don't even know what code you run, or what hardware you have, there's no dmesg... As an aside, tc_init(9) is a good starting point if you want to learn about the timecounter code.
