Strange. I am testing on FreeBSD-10-stable though.May be you add return code check for cpuset_setaffinity() and log possible error?
That might be relevant. My FreeBSD-10.0 test server does also exhibit the expected behavior.
# cpuset -g -p 71215 pid 71215 mask: 2, 3, 4, 5, 6, 7, 8 # cpuset -g -p 71216 pid 71216 mask: 7, 8, 9, 10, 11, 12, 13, 14 Best, -Mark
