What is interrupt latency and how to reduce it - Embedded Systems Interview Question

Interrupt latency refers to the time delay between when an interrupt request is generated by a device and when the processor starts executing the corresponding interrupt service routine (ISR). High interrupt latency can impact the responsiveness and real-time capabilities of embedded systems.

To reduce interrupt latency in embedded systems, consider the following strategies:

1. Optimize the interrupt handling process: Write efficient ISR code that minimizes the time spent in critical sections. Avoid unnecessary delays and computations within the ISR.
2. Use prioritized interrupts: Assign priorities to different types of interrupts to ensure that critical tasks are serviced quickly. This helps in reducing the latency for important interrupts.
3. Minimize interrupt nesting: Avoid nesting interrupts whenever possible, as nested interrupts can increase latency. Prioritize interrupt handling based on the criticality of tasks.
4. Consider hardware acceleration: Use hardware features such as interrupt controllers, DMA controllers, and dedicated interrupt handling mechanisms to offload interrupt processing from the main CPU.
5. Optimize system design: Architect the system to minimize shared resources and contention that can lead to increased interrupt latency. Use asynchronous processing and parallel execution where applicable.

By implementing these strategies, developers can effectively reduce interrupt latency in embedded systems and improve overall system performance and responsiveness.