Chapter 1.9, Problem 1.2PP

Program Plan Intro

Amdahl’s Law:

• It denotes an observation on effectiveness of performance improving of a system part.
• The main idea is that when one system part is been speed up the effect on overall system would depend on significance and speed up of the part.
• Suppose the execution of an application needs “T_old” time.
• Some part of system may require a fraction “α” of this time and the performance is improved by a factor of “k”.
• The overall execution time will be “$T_{new}=T_{old}[(1-\alpha )+\alpha /k]$ ”.
• The speed up can be computed as “$S=T_{old}/T_{new}$”.
• Hence, the expression for speed up is “$S=1/(1-\alpha )+\alpha /k$”.