Voilà les résultats :
top - 20:58:20 up 5:04, 2 users, load average: 1.06, 1.29, 1.39
Tasks: 157 total, 3 running, 154 sleeping, 0 stopped, 0 zombie
Cpu(s): 13.8%us, 17.6%sy, 0.0%ni, 37.1%id, 29.0%wa, 0.5%hi, 2.1%si, 0.0%st
Mem: 2061616k total, 1860600k used, 201016k free, 785440k buffers
Swap: 0k total, 0k used, 0k free, 562748k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
31212 laurenco 20 0 505m 169m 34m S 23 8.4 21:46.45 firefox
2558 laurenco 20 0 24732 4012 2768 S 3 0.2 3:53.55 gvfs-gdu-volume
1165 root 20 0 179m 43m 12m S 3 2.1 4:19.87 Xorg
2032 laurenco 20 0 276m 125m 3792 S 3 6.2 0:20.56 pulseaudio
967 messageb 20 0 3268 1628 748 S 3 0.1 2:52.53 dbus-daemon
2551 root 20 0 8272 6120 2324 S 2 0.3 3:00.20 devkit-disks-da
27961 laurenco 20 0 39288 12m 9848 R 2 0.6 0:00.59 gnome-terminal
1 root 20 0 2660 1552 1120 S 2 0.1 1:30.25 init
692 root 18 -2 2768 1160 308 S 2 0.1 1:45.69 udevd
2526 laurenco 20 0 18348 7396 5468 S 2 0.4 1:25.33 gdu-notificatio
2532 laurenco 20 0 29612 12m 8808 S 1 0.6 1:44.96 update-notifier
483 root 20 0 2584 1412 1000 R 0 0.1 1:06.96 mountall
497 root 20 0 2148 760 568 S 0 0.0 0:24.20 upstart-udev-br
28110 laurenco 20 0 2468 1184 884 R 0 0.1 0:00.20 top
2 root 15 -5 0 0 0 S 0 0.0 0:00.00 kthreadd
3 root RT -5 0 0 0 S 0 0.0 0:00.09 migration/0
4 root 15 -5 0 0 0 S 0 0.0 0:01.40 ksoftirqd/0
5 root RT -5 0 0 0 S 0 0.0 0:00.00 watchdog/0
9 root 15 -5 0 0 0 S 0 0.0 0:00.11 events/0
11 root 15 -5 0 0 0 S 0 0.0 0:00.00 cpuset
12 root 15 -5 0 0 0 S 0 0.0 0:00.00 khelper
et quelques instants après :
top - 20:59:25 up 5:05, 2 users, load average: 0.93, 1.20, 1.35
Tasks: 157 total, 4 running, 153 sleeping, 0 stopped, 0 zombie
Cpu(s): 13.2%us, 10.0%sy, 0.0%ni, 41.8%id, 33.7%wa, 0.3%hi, 1.0%si, 0.0%st
Mem: 2061616k total, 1802892k used, 258724k free, 786156k buffers
Swap: 0k total, 0k used, 0k free, 530180k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
31212 laurenco 20 0 409m 142m 33m S 7 7.1 22:00.75 firefox
967 messageb 20 0 3268 1628 748 S 4 0.1 2:54.09 dbus-daemon
2558 laurenco 20 0 24732 4012 2768 S 3 0.2 3:55.70 gvfs-gdu-volume
2551 root 20 0 8272 6120 2324 S 3 0.3 3:01.89 devkit-disks-da
1165 root 20 0 179m 42m 11m S 2 2.1 4:21.65 Xorg
27961 laurenco 20 0 39416 13m 9904 S 2 0.6 0:01.40 gnome-terminal
1 root 20 0 2660 1552 1120 S 2 0.1 1:31.17 init
692 root 18 -2 2768 1160 308 S 2 0.1 1:46.61 udevd
499 root 16 -4 2772 1128 300 S 1 0.1 0:39.40 udevd
2526 laurenco 20 0 18348 7400 5468 S 1 0.4 1:26.11 gdu-notificatio
2532 laurenco 20 0 29612 12m 8808 S 1 0.6 1:45.93 update-notifier
30347 laurenco 20 0 2468 1184 884 R 1 0.1 0:00.16 top
4 root 15 -5 0 0 0 S 0 0.0 0:01.41 ksoftirqd/0
483 root 20 0 2584 1412 1000 S 0 0.1 1:07.35 mountall
2553 root 20 0 4820 752 500 D 0 0.0 0:04.38 devkit-disks-da
2 root 15 -5 0 0 0 S 0 0.0 0:00.00 kthreadd
3 root RT -5 0 0 0 S 0 0.0 0:00.10 migration/0
5 root RT -5 0 0 0 S 0 0.0 0:00.00 watchdog/0
9 root 15 -5 0 0 0 S 0 0.0 0:00.11 events/0
11 root 15 -5 0 0 0 S 0 0.0 0:00.00 cpuset
12 root 15 -5 0 0 0 S 0 0.0 0:00.00 khelper
Donc on ne voit pas de processus anormal, pourtant le CPU est utilisé (alors qu'il n'y avait que Firefox et, évidement, le terminal que j'avais comme applications lancées)