Comment 31 for bug 1303649

FWIW I'm experiencing similar symptoms on an ancient desktop that has been stable, reliable and used every day for years. I too ran dist-upgrade a couple of days ago. I've no idea what repos I use. That config hasn't been touched for a long time. Can investigate if the information might be useful.

$ top -b -n 1 | head
top - 19:17:12 up 1 day, 11:17, 2 users, load average: 1.74, 1.65, 1.96
Tasks: 191 total, 2 running, 189 sleeping, 0 stopped, 0 zombie
%Cpu(s): 47.8 us, 51.4 sy, 0.3 ni, 0.3 id, 0.1 wa, 0.0 hi, 0.1 si, 0.0 st
KiB Mem: 1025144 total, 720844 used, 304300 free, 171616 buffers
KiB Swap: 1048572 total, 30508 used, 1018064 free. 190468 cached Mem

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
  353 root 20 0 3076 1172 1068 R 31.6 0.1 922:38.21 cgmanager
  892 root 20 0 4216 1344 1248 S 31.6 0.1 911:28.89 systemd-logind
 1539 root 20 0 89256 37060 14232 S 7.9 3.6 45:56.98 Xorg
$ uname -a
Linux lab-netvista 3.13.0-87-generic #133-Ubuntu SMP Tue May 24 18:33:01 UTC 2016 i686 i686 i686 GNU/Linux
zaphod@lab-netvista:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.5 LTS
Release: 14.04
Codename: trusty