Polling is a technique used in computer systems to continuously check the status of a device or resource by the CPU. Instead of relying on external events to trigger actions, the CPU actively queries the device to determine if it needs . Polling is commonly used in situations where the latency of handling the device's requests is predictable and consistent. It's often employed in simple systems where the overhead of is unnecessary, such as polling for keyboard input in simple embedded systems.
The advantages of polling include its , which makes it relatively straightforward to implement and understand, and the it offers the CPU over when to check the status of a device, allowing for precise timing and coordination. However, polling also has its disadvantages, such as inefficiency, because it can tie up the CPU, especially if the device doesn't require immediate attention, leading to wasted CPU cycles. Additionally, continuous polling may result in high , consuming system resources unnecessarily.
In contrast, interrupts are a mechanism used in computer systems to handle asynchronous events. When a device requires attention, it interrupts the CPU's normal execution flow, causing it to suspend its current operation and jump to an interrupt routine. Interrupts are essential in real-time systems where timely responses to external events are critical, and they facilitate multitasking by allowing the CPU to switch between tasks efficiently. The effectiveness of interrupts comes from their , low latency, and event-driven nature, which reduces overall system overhead.
Despite their advantages, interrupts can also introduce challenges. Implementing interrupts can be more than polling due to the need for interrupt handlers and managing interrupt priorities. Furthermore, while interrupts reduce overall system overhead, handling multiple interrupts and prioritizing them can introduce and complexity. In interrupt-driven systems, synchronization mechanisms may be required to ensure data consistency and prevent race .
Keywords
conditions | service | control | overhead | overhead | efficiency | simplicity | complex | handler | interrupts |
