Amdahl's Law Calculator

Formula

The formula to calculate speedup according to Amdahl's Law is:

$\text{Speedup} = \frac{1}{(1 - p) + \frac{p}{n}}$

Where:

$\text{Speedup}$ is the overall speedup achieved by parallel processing
$p$ is the proportion of the program that can be parallelized (between 0 and 1)
$n$ is the number of processors used

What is Amdahl's Law?

Amdahl's Law, named after computer architect Gene Amdahl, is a formula used to find the maximum improvement possible by enhancing a particular part of a system. In the context of parallel computing, it is used to predict the theoretical maximum speedup for program processing using multiple processors. The law states that the speedup of a program using a parallel algorithm is limited by the time needed for the sequential fraction of the program. This means that the speedup is limited by the non-parallelizable section of the process.

Example Calculation

Let's assume the following values:

Proportion of Program that can be Parallelized (p) = 0.8
Number of Processors (n) = 4

Using the formula to calculate Speedup:

$\text{Speedup} = \frac{1}{(1 - 0.8) + \frac{0.8}{4}} = \frac{1}{0.2 + 0.2} = \frac{1}{0.4} = 2.5$

The Speedup is 2.5.