What is Interrupt?

What is Interrupt?

An interrupt is a signal sent to the computer’s processor asking it to stop what it’s doing and start handling the interrupt right away. Devices like the keyboard, mouse and network card communicate with the processor and request services using interrupts. They are crucial to how modern operating systems function and enable the processor to react quickly to outside events. The interrupt can be emitted by hardware or software indicating an event that needs immediate attention....

Types of Interrupts

1. Software Interrupt...

What is Interrupt latency?

Interrupt latency is the time that elapses between the occurrence of an interrupt and the execution of the first instruction of the interrupt service routine (ISR) that handles the interrupt....

Importance of Interrupt Latency

Interrupt latency is an important consideration in the design and optimization of real-time and embedded systems. These systems often have hard real-time constraints, meaning that they must respond to external events within a specified time period....

Factors Affecting Interrupt Latency

There are several factors that can affect interrupt latency, including:...

Interrupt Prioritization

When a processor receives a higher-priority interrupt while it is still addressing a lower-priority interrupt, this is known as interrupt preemption. In this scenario, the processor will instantly halt the handler for the current interrupt and start the handler for the interrupt with a higher priority....

Arm Cortex-M Interrupts Latency

The ARM Cortex-M microcontroller series has a low interrupt latency and is frequently used in embedded systems. The nested vectored interrupt controller (NVIC) on Cortex-M processors enables effective interrupt handling. Between the time the interrupt occurs and the time the processor starts executing the interrupt service routine, there are only a few instructions in the NVIC (ISR)....

Measuring Interrupt Latency

Interrupt latency can be measured using various techniques, such as the use of specialized hardware, software tools, and benchmarks. It’s also possible to use different system performance monitoring tools to measure interrupt latency. It’s important to note that the way of measuring can affect the results as well, some tools or methods might measure only the time from the interrupt request to the ISR start while others may include other events as well such as disabling interrupt or switch process, etc. There are three types of latency that are measured:...

Conclusion

Interrupt latency is a measure of the time it takes for a computer system to respond to an external event. It is an important metric in determining the performance and responsiveness of a system, particularly in real-time and embedded systems. Factors such as hardware, operating system, interrupt priority, and system load can all affect interrupt latency. Measuring interrupt latency can be done using various techniques and tools. It is important for system designers and developers to understand and optimize interrupt latency in order to ensure the reliability and performance of their systems....