The terms "top half" and "bottom half" are the two distinct parts of handling types of interrupt-driven events. These terms describes a mechanism for splitting the processing of interrupts into different stages.
Top Half: also called as the "interrupt handler" or "interrupt service routine" (ISR), executes atomically in response to an interrupt being raised by a device. The top half is responsible for performing time- critical tasks that needs immediate attention, such as acknowledging the interrupt, saving relevant data, and delegating futher(or remaining) activity to bottom half (such as tasklets or workques).
Top Half: also called as the "interrupt handler" or "interrupt service routine" (ISR), executes atomically in response to an interrupt being raised by a device. The top half is responsible for performing time- critical tasks that needs immediate attention, such as acknowledging the interrupt, saving relevant data, and delegating futher(or remaining) activity to bottom half (such as tasklets or workques).
Bottom Half: also called to as the "deferred work" or "deferred handler," is executed asynchronously at a later time, usually after the interrupt (top half) has been serviced. It handles the non-time-critical or time-consuming tasks associated with the interrupt. These tasks could include updating data structures, processing large data sets or performing I/O operations.
The reason of splitting between the top half and the bottom half is a way to achieve efficient handling of interrupts without blocking the normal execution flow. By quickly handling the time-critical part in the top half and deferring the non-time-critical tasks to the bottom half, the system can respond to interrupts promptly while minimizing the impact on the overall system performance.
There are different bottom half mechanisms in Linux, such as tasklets, work queues, and kernel threads. Each mechanism provides a way to schedule and execute.
The reason of splitting between the top half and the bottom half is a way to achieve efficient handling of interrupts without blocking the normal execution flow. By quickly handling the time-critical part in the top half and deferring the non-time-critical tasks to the bottom half, the system can respond to interrupts promptly while minimizing the impact on the overall system performance.
There are different bottom half mechanisms in Linux, such as tasklets, work queues, and kernel threads. Each mechanism provides a way to schedule and execute.