Andrew S. Tanenbaum (OS) Edition 4 Exercise 5 Question 37 (Page No. 432)

Question

The clock interrupt handler on a certain computer requires $2\: msec$ (including process switching overhead) per clock tick. The clock runs at $60\: Hz.$ What fraction of the CPU is devoted to the clock?

Answer 1

$2\;\text{msec}$ $\;60 $ times a second $=120 \;\frac{\text{msec}}{\text{sec}}=12\%\;\text{of the CPU time}$