Polling vs interrupts. A program is outputting a series of blocks by repeatedly issuing an I/O instruction. • Executing the I/O instruction takes 1 unit of CPU time. All other instructions take 0 units of time. • The device starts at the end of the I/O instruction and remains busy for 6 time units. • When polling is used, the CPU polls the device every 5 time units. • A poll takes 1 unit of CPU time. • When interrupts are used, the interrupt handler takes 3 time units to process the interrupt. Draw a timing diagram showing when the CPU and the device are busy during the first 24 time units
1. with polling
2. with interrupts