Virtualized /proc File System (LVE 0.7 and higher)
You can prevent user from seeing processes of other users (via ps/top command) by setting:
/proc/sys/fs/proc_can_see_other_uid to 0
You can also add a users to a special group, members of which will see all processes (kernel lve0.8.42 and later)
To do that, edit /etc/sysctl.conf
# SecureLVE fs.proc_can_see_other_uid=0 # lve0.8.42 and later fs.proc_super_gid=600
And do:
# sysctl -p