Using the Polling method to calculate the cpu efficiency cpu

Using the Polling method to calculate the cpu efficiency:

cpu speed is 2 million instructions/ second

the device operates at 200 characters/second

The polling loop has 200 instructions

You need to calculate how many times is the loop done and what is the cpu efficiency?

One character=8 bits or 1 byte.

so device speed=200x1=200 instructions per second

So this device should be polled using at least this rate.

CPU speed=2X10^6 instructions per second

CPU efficency=(200x200)/(2x10^6)=0.02%