Product Management question :

Problem: In this exercise, assume that we are considering enhancing a quad-code machine by adding encryption hardware to it (as opposed to supporting such features in software). When computing encryption operations, it is 20 times faster that the previous mode of execution. We will define ‘percentage of encryptions’ as the percentage of time in the original execution that is spent performing encryption operations. The specialized hardware increases power consumption by 2%.

Draw a graph that plots the speedup as a percentage of the computation spent performing encryption. Label the y-axis ‘Net Speedup’ and the x-axis ‘Percent Encryption’.

With what percentage of encryption will adding encryption hardware result in a speedup of 2?

What percentage of time in the new execution will be spent on encryption operations if a speedup of 2 is achieved?

Suppose you have measured the typical percentage of encryption to be 50%. The hardware design group estimates that it can speed up the encryption hardware even more with significant additional investment. You wonder whether adding a second unit in order to support parallel encryption operations would be more useful. Imagine that in the typical use case, 90% of the encryption operations can be done in parallel. What is the speed up of providing 2 or 4 encryption units, assuming that the parallelization allowed is limited to the number of encryption units?