Interrupt Latency

Interrupts are signals that are used to interrupt the normal flow of a program and transfer control to an interrupt service routine. Interrupt latency is the time between the occurrence of an interrupt and the start of the interrupt service routine. It is the time taken by the system to recognize the interrupt, save the current context, and transfer control to the interrupt service routine.

Factors affecting Interrupt Latency

The interrupt latency depends on several factors, including:

1. Hardware architecture: The hardware architecture of the system plays a key role in determining the interrupt latency. The interrupt controller and the processor's interrupt handling mechanism are important factors.

2. Interrupt Priority: Interrupts are assigned priority levels, and the higher priority interrupts are serviced first. The system must check for pending interrupts before servicing the current interrupt, which can increase the interrupt latency.

3. Interrupt Service Routine (ISR) Overhead: The ISR overhead includes the time taken to save and restore the context, access shared resources, and execute the ISR code. The larger the ISR overhead, the higher the interrupt latency.

4. System Load: The system load, or the number of processes running on the system, can affect the interrupt latency. A high system load can increase the time taken to service an interrupt.

Conclusion

Interrupt latency is an important factor that can affect the performance and responsiveness of a system. System designers must carefully consider the hardware architecture, interrupt handling mechanism, and ISR overhead when designing systems that require fast and efficient interrupt handling.