Speedup

Speedup (English for acceleration) is a term used in computer science and mathematically describes the relationship between the serial and the parallel execution time of a program part.

Definition

The speedup is defined by the following two formulas:

Wherein:

  • Is the number of processors
  • Is the theoretical speedup can be achieved when running the algorithm on the processors
  • Is the running time on a single-processor system
  • Is the running time on a multi-processor system
  • (English fraction), the proportion of which can be executed in parallel

Range of values

Applies Ideally,

So therefore the execution time of processors is exactly times faster than on a single processor. However, since an algorithm can never be executed completely 100% parallel, because there is always a sequential non- parallelizable portion, the ideal situation is never reached (see Amdahlsches Act).

The range of values ​​can therefore be set with

Wherein the speedup is only 1 if the complete algorithm is not parallelized, and is therefore processed on a plurality of processors as fast as in a single processor.

Run time (program lifecycle phase)
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