Where is a tick injection given?

Where is a tick injection given? - briefly

A tick injection is supplied as an argument to the function that requires it, typically at the call site where the function is invoked.

Where is a tick injection given? - in detail

A tick injection is supplied by the component that generates periodic time‑step signals for the system being observed. In most software environments the source is a timer mechanism that triggers at a fixed interval and calls a handler responsible for advancing the simulation or scheduling tasks.

The handler is typically placed in one of the following locations:

• Kernel timer interrupt routine – the hardware timer raises an interrupt; the interrupt service routine updates the system tick counter and awakens waiting threads.
• Real‑time operating system scheduler – the scheduler receives the tick from a dedicated timer driver and performs context switches or deadline checks.
• Game or physics engine main loop – a function called once per frame or fixed‑step interval invokes the tick injection, often named Update, Step, or Tick.
• Simulation framework event queue – a scheduler object inserts a tick event into the event queue at predetermined timestamps; the event processor then executes the tick logic.
• Testing harness or mock timer – a test utility explicitly calls a tick injection function to simulate the passage of time without relying on real hardware.

The injection point must be early enough in the processing cycle to allow all subsystems to observe the new tick value before they perform their own work. Consequently, the tick handler is usually the first routine executed after the timer interrupt is acknowledged, or the first call in the main loop before any game logic, I/O handling, or user‑level processing occurs.

In embedded systems the tick injection may be delivered by a watchdog or a dedicated peripheral that generates a periodic signal directly to the CPU. In virtualized environments the hypervisor can provide a synthetic timer, and the guest OS receives the tick via a virtual interrupt.

Overall, the tick injection originates from the system’s timing source and is delivered to the central scheduling component, which then propagates the tick to all dependent modules. This placement guarantees deterministic timing and consistent state updates across the entire software stack.