# Amdahl's law of processors (infinite processors to test limits of speedup)

My processor noted that an infinite number of processors will allow me to test how much speedup I can achieve.

I am not exactly sure how this applies.

For instance, let's say I have a program that takes $1000$ seconds to execute and is broken into 4 phases(A, B, C, D). If two of the phases are $50%$ parallelizable and the other $2$ are not parallelizable at all, how can I apply the concept that I have infinite available processors to figure out how much maximum speed up I can achieve?

I attached numbers to my example, but a generic one would be just as helpful.

If I am to strictly just apply Amdahl's law, I'd say the answer is just $1/(1-0.5) = 2$ times faster.

• When you say that it's "50 parallelizable", do you mean that two of the phases can be sped up 50 times due to parallelization? – J. Antonio Perez Apr 24 '17 at 16:07