Amdahl's Law
Understanding the fundamental limit of performance optimization
Amdahl’s Law is a fundamental principle in performance optimization. It describes the theoretical speedup you can achieve when improving a portion of the program. It’s named after computer architect Gene Amdahl, who formulated it in 1967.
The core idea is that when a part of the system is optimized its overall impact on the system depends on two factors: how significant this part was and how much it was sped up.
The Formula
The speedup is given by:
Speedup = 1 / ((1 - α) + α/k)Where:
- α how significant this part is to the overall system (0 to 1)
- k the speed up factor
- (1 - α) is the part we’re not optimizing