Ubuntu ‘watchdog’ process

I was using top recently to see what processes were running. Everything looked fined but the watchdog process looked like it didn’t match with the rest of the processes.

barbara@barbara-desktop:~$ barbara@barbara-desktop:~$ top
Tasks: 164 total,   2 running, 162 sleeping,   0 stopped,   0 zombie
Cpu(s): 25.0%us, 25.0%sy,  0.0%ni, 50.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   2836916k total,  1872104k used,   964812k free,   125044k buffers
Swap:  1861624k total,        0k used,  1861624k free,   622060k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 8182 barbara   20   0  2548 1208  904 R   69  0.0   0:00.43 top
    1 root      20   0  2780 1624 1164 S    0  0.1   0:00.42 init
    2 root      20   0     0    0    0 S    0  0.0   0:00.00 kthreadd
    3 root      RT   0     0    0    0 S    0  0.0   0:00.00 migration/0
    4 root      20   0     0    0    0 S    0  0.0   0:00.13 ksoftirqd/0
    5 root      RT   0     0    0    0 S    0  0.0   0:00.00 watchdog/0
    6 root      RT   0     0    0    0 S    0  0.0   0:00.01 migration/1
    7 root      20   0     0    0    0 S    0  0.0   0:00.12 ksoftirqd/1
    8 root      RT   0     0    0    0 S    0  0.0   0:00.00 watchdog/1
    9 root      20   0     0    0    0 S    0  0.0   0:00.26 events/0
   10 root      20   0     0    0    0 S    0  0.0   0:00.32 events/1
   11 root      20   0     0    0    0 S    0  0.0   0:00.00 cpuset
   12 root      20   0     0    0    0 S    0  0.0   0:00.00 khelper
   13 root      20   0     0    0    0 S    0  0.0   0:00.11 netns
   14 root      20   0     0    0    0 S    0  0.0   0:00.00 async/mgr
   15 root      20   0     0    0    0 S    0  0.0   0:00.00 pm
   17 root      20   0     0    0    0 S    0  0.0   0:00.01 sync_supers

A quick search on ubuntu packages leads to the watchdog page which summarizes the package like so:

The watchdog program writes to /dev/watchdog every ten seconds. If the device is opened but not written to within a minute, the machine will reboot. This feature is available when the kernel is built with ‘software watchdog’ support (standard in Debian kernels).

The ability to reboot will depend on the state of the machine and interrupts.

With that said, I still don’t know the purpose of it. It’s really not something you want to mess with.