Just a quick success report - kern/120138 does indeed solve the Phenom X3 SCHED_ULE problem. Attached patch against recent -STABLE in case someone else runs into it in the near future: --- sys/kern/sched_ule.c.orig 2008-12-08 05:07:30.000000000 +0100 +++ sys/kern/sched_ule.c 2009-03-11 00:09:43.000000000 +0100 @@ -1399,7 +1399,7 @@ * prevents excess thrashing on large machines and excess idle on * smaller machines. */ - steal_thresh = min(ffs(mp_ncpus) - 1, 4); + steal_thresh = min(fls(mp_ncpus) - 1, 4); affinity = SCHED_AFFINITY_DEFAULT; #endif }