Chapter 9
What is Amdahl's law? What problem does Amdahl's law look to solve?
Amdahl's law provides an estimate of the theoretical speedup in latency of the execution of a task at fixed workload that can be expected of a system whose resources are improved.
Explain the formula of Amdahl's Law, along with its components.
The formula for Amdahl's Law is as follows:
In the preceding formula, the following applies:
- S is the theoretical speedup in consideration.
- B is the portion of the whole task that is inherently sequential.
- j is the number of processors being utilized.
According to Amdahl's Law, would speedup increase indefinitely as resources in the system improved?
No; as the number of processors becomes larger, the efficiency gained through the improvement decreases.
What is the relationship between Amdahl's Law and the law of diminishing returns?
You have seen that in specific situations (namely, when only the number of processors increases), Amdahl's Law resembles the law of diminishing returns. Specifically, as the number of processors becomes larger, the efficiency gained through the improvement decreases, and the speedup curve flattens out.
