This is an update to an earlier report. The current version of cups (debian sid is 2.2.1-5)
The following is documented below. Upon reboot, cupsd is started and pegs one CPU systemctl stop cups systemctl start cups resets the errant behavior, and cups operates normally. This is easily repeatable (on my system); it happens whenever the system is rebooted. Some details: After reboot: ps aux | grep cups root 826 96.5 0.1 141820 52552 ? Rs 08:33 2:26 /usr/sbin/cupsd -l root 879 0.0 0.0 95016 208 ? Ssl 08:33 0:00 /sbin/apcupsd root 892 0.2 0.0 262260 10892 ? Ssl 08:33 0:00 /usr/sbin/cups-browsed lp 924 0.0 0.0 83956 5740 ? S 08:34 0:00 /usr/lib/cups/notifier/dbus dbus:// lp 926 0.0 0.0 83956 5800 ? S 08:34 0:00 /usr/lib/cups/notifier/dbus dbus:// lp 966 0.0 0.0 83956 5728 ? S 08:34 0:00 /usr/lib/cups/notifier/dbus dbus:// trs 3563 0.7 0.1 361884 52432 pts/4 Sl 08:35 0:00 emacs cups.txt trs 3576 0.0 0.0 12784 968 pts/4 S+ 08:36 0:00 grep --color=auto cups systemctl stop cups ps aux | grep cups root 879 0.0 0.0 95016 208 ? Ssl 08:33 0:00 /sbin/apcupsd trs 3563 0.4 0.1 361884 52584 pts/4 Sl 08:35 0:00 emacs cups.txt trs 3586 0.0 0.0 12784 936 pts/4 S+ 08:37 0:00 grep --color=auto cups systemctl start cups ps aux | grep cups root 879 0.0 0.0 95016 208 ? Ssl 08:33 0:00 /sbin/apcupsd trs 3563 0.3 0.1 361884 52584 pts/4 Sl 08:35 0:00 emacs cups.txt root 3593 0.5 0.0 106924 17816 ? Ss 08:37 0:00 /usr/sbin/cupsd -l lp 3595 0.0 0.0 83956 5676 ? S 08:37 0:00 /usr/lib/cups/notifier/dbus dbus:// lp 3596 0.0 0.0 83956 5632 ? S 08:37 0:00 /usr/lib/cups/notifier/dbus dbus:// lp 3597 0.0 0.0 83956 5712 ? S 08:37 0:00 /usr/lib/cups/notifier/dbus dbus:// trs 3601 0.0 0.0 12784 940 pts/4 S+ 08:37 0:00 grep --color=auto cups dpkg -l | grep '^ii cups' ii cups 2.2.1-5 ii cups-browsed 1.11.6-2 ii cups-bsd 2.2.1-5 ii cups-client 2.2.1-5 ii cups-common 2.2.1-5 ii cups-core-drivers 2.2.1-5 ii cups-daemon 2.2.1-5 ii cups-filters 1.11.6-2 ii cups-filters-core-drivers 1.11.6-2 ii cups-pk-helper 0.2.6-1 ii cups-ppdc 2.2.1-5 ii cups-server-common 2.2.1-5
