Explain speedup, efficiency and scalability with suitable example.

Q. Explain speedup, efficiency and scalability with suitable example. (MAY 19, MAY 17) 10M

Ans- 1. Speedup

The speedup is defined as the ratio of the serial runtime of the best sequential algorithm for solving a problem to the time taken by the parallel algorithm to solve the same problem on p processors.

Example Adding n numbers on an n processor hypercube

2. Efficiency

The efficiency is defined as the ratio of speedup to the number of processors. Efficiency measures the fraction of time for which a processor is usefully utilized.

Example Efficiency of adding n numbers on an n‐processor hypercube

3. Scalability

Scalability is a measure of a parallel system’s capacity to increase speedup in proportion to the number of processors.

Example Adding n numbers cost‐optimally