Question

Consider a system such that the number of clock cycles for a polling operation (including transferring to the polling routine,
accessing the device and restarting the user program) is 400 cycles,
and that the processor executes with a 500 MHz clock. Determine the fraction of CPU consumed when the mouse must be polled 30 times per second.

•0.002 %
•0.02 %
•0.2 %
•None of these

Answer 1

Number of cycles per second required=30 times per second *400 cycles per polling operation =12000 cycles per sec

FractFraof cpu consumed=(required frequency /cpu frequency) *100=12000/500×10^6

=0.0024

Correct answer is 0.002% or 0.0024%