Just ran a stress test on 6.1-PRELEASE, and got : davidxu at tiger:/home/davidxu/stress2/testcases/thr1> ./thr1 Feb 24 08:02:10 tiger login: ROOT LOGIN (root) ON ttyv1 calcru: runtime went backwards from 39012220 usec to 39011621 usec for pid 789 ( thr1) calcru: runtime went backwards from 45138436 usec to 45138007 usec for pid 789 ( thr1) David Xu