WatchdogTimeouts

WatchdogTimeouts refers to the configured time window within which a watchdog mechanism must be refreshed to indicate normal operation. A watchdog timer is a hardware or software timer that runs independently from the main processor. If the monitored software or component fails to reset or “kick” the timer within the allotted interval, the timer expires and triggers a predefined action, such as a system reset, an interrupt, or an alert.

There are several implementations of watchdog timeouts. Hardware watchdog timers are built into many microcontrollers and dedicated chips, often connected to a system reset line. Software watchdogs are implemented within operating systems or applications to monitor critical tasks. External or networked watchdogs may observe heartbeats from multiple components and raise alerts when expected signals are missing.

Configuration and behavior vary. Typical timeouts range from tens of milliseconds in fast embedded systems to several seconds or more in less time-critical environments. The timeout value is chosen to balance prompt failure detection with robustness against transient delays. Some watchdogs are retriggerable, meaning the timer restarts with each successful feed, while others are non-retriggerable and expire once. The expiry action can be a reset, a software interrupt, or a notification to a supervisory system.

Usage considerations include tuning for reliability, particularly in safety-critical or high-availability systems. Debugging can be challenging because a watchdog may reset the system during development; many implementations offer mechanisms to disable, extend, or observe feeds during testing. In Linux, for example, the watchdog subsystem exposes devices such as /dev/watchdog to manage hardware or software watchdog timers. Related concepts include watchdog timers, heartbeat signals, and system resets.