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Amdahl's law

The part of a job that can't be split up limits how much faster more cores can make it.

Amdahl's law bounds speed-up on N processors by 1 / ((1 - p) + p / N), where p is the fraction of the work that can run in parallel.

Examples

  • If 20% of a job has to run on one core, even unlimited cores can make it at most 5 times faster.

See also

parallelism benchmark
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