a.out is a CPU-bound process that spins at 100% reading and writing memory in a loop, with 32 copies running in parallel on the 48-core system, so I'd expect to see all of them reporting 100% CPU. A snapshot of top looks like: PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND 822 root 1 103 0 1030M 1024M CPU2 2 34:38 1779.83% a.out 819 root 1 103 0 1030M 1026M CPU17 17 34:41 458.17% a.out 817 root 1 103 0 1030M 1026M CPU44 44 34:41 444.14% a.out 815 root 1 103 0 1030M 1026M CPU42 42 34:41 444.14% a.out 806 root 1 103 0 1030M 1012M CPU38 38 34:44 356.67% a.out 807 root 1 103 0 1030M 1013M CPU30 30 34:44 356.24% a.out 812 root 1 103 0 1030M 1021M CPU5 5 34:41 31.81% a.out 837 root 1 20 0 7660K 1896K CPU25 25 3:16 1.63% top 809 root 1 103 0 1030M 1020M CPU32 32 34:41 0.00% a.out 814 root 1 103 0 1030M 1021M CPU26 26 34:40 0.00% a.out 811 root 1 103 0 1030M 1020M CPU45 45 34:40 0.00% a.out 810 root 1 103 0 1030M 1016M CPU24 24 34:40 0.00% a.out 805 root 1 103 0 1030M 995M CPU29 29 34:38 0.00% a.out 820 root 1 103 0 1030M 1016M CPU33 33 34:38 0.00% a.out 821 root 1 103 0 1030M 1020M CPU8 8 34:37 0.00% a.out 818 root 1 103 0 1030M 1005M CPU19 19 34:37 0.00% a.out 808 root 1 103 0 1030M 1005M CPU36 36 34:36 0.00% a.out Sometimes many process report 400% or so, sometimes only a few.
See r288216 https://svnweb.freebsd.org/changeset/base/288216
Addressed by r288216