Amdahl's Law

What is Amdahl's Law?

Speedup from parallelisation is limited by the fraction of a task that must remain sequential. Even with an infinite number of processors, a task that's 10% inherently sequential can never speed up by more than a factor of ten.

The five clues

Engineerdle #56 described Amdahl's Law with five clues, revealed one at a time from hardest to most direct. Each clue points at a different property of the concept.

1. 01A sobering law about diminishing returns.
2. 02It applies when you throw more hardware at a problem.
3. 03The serial fraction of the work sets a hard ceiling.
4. 04Even with infinite processors, speedup converges to a finite number.
5. 05Named after the architect of the IBM System/360.