WDOGCTL(8) | System Manager's Manual | WDOGCTL(8) |
wdogctl
— Watchdog
timer control utility
wdogctl |
wdogctl |
-d |
wdogctl |
-e [-A ]
[-p seconds]
timer |
wdogctl |
-k [-A ]
[-p seconds]
timer |
wdogctl |
-t |
wdogctl |
-u [-A ]
[-p seconds]
timer |
wdogctl |
-x [-A ]
[-p seconds]
timer |
wdogctl
is used to manipulate watchdog
timers. A watchdog timer is a hardware or software timer that resets the
system if it fails to make progress within a prescribed period. To prevent
the system from being reset, something must refresh the timer to prevent it
from expiring.
A hardware watchdog timer asserts system's hardware reset signal when it expires. A software watchdog timer calls the kernel's s normal reboot path.
The NetBSD kernel provides three modes in which watchdog timers may operate: kernel tickle mode, user tickle mode, and external tickle mode.
wdogctl
runs in the background and refreshes the
watchdog timer. This ensures user programs can make progress within the
period of the watchdog timer.
Note that user tickle mode must be used with caution; on a
heavily loaded system, the timer may expire accidentally, even though
user programs may be making (very slow) progress. A user-mode timer is
disarmed (if possible) when the device is closed, unless the timer is
activated with the -x
option.
wdogctl
-t
. This allows users to determine the activity
whose progress the watchdog timer checks.In kernel and user tickle modes, an attempt is made to refresh the watchdog timer in one half the timer's configured period. For example, if the watchdog timer has a period of 30 seconds, a refresh attempt is made every 15 seconds.
If called without arguments, wdogctl
will
list the timers available on the system. When arming a watchdog timer, the
timer argument is the name of the timer to arm.
Only one timer may be armed at a time; if an attempt is made to arm a timer when one is already armed, an error message will be displayed and no action will be taken.
The options are as follows:
-A
-d
-e
-k
-p
period-t
-u
-x
acpiwdrt(4), evbarm/iopwdog(4), i386/elansc(4), i386/gcscpcib(4), i386/geodewdog(4), ipmi(4), itesio(4), pcweasel(4), pwdog(4), swwdog(4), x86/tco(4)
The wdogctl
command first appeared in
NetBSD 1.6.
The wdogctl
command and the
NetBSD watchdog timer framework were written by
Jason R. Thorpe ⟨thorpej@zembu.com⟩,
and contributed by Zembu Labs, Inc.
July 11, 2020 | NetBSD 10.99 |