Differences between revisions 7 and 32 (spanning 25 versions)
Revision 7 as of 2005-06-27 22:15:58
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Editor: yakko
Comment:
Revision 32 as of 2020-01-23 23:15:20
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Editor: scot
Comment:
Deletions are marked like this. Additions are marked like this.
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{{{#!latex
\begin{equation}
   Speedup = \frac{Performance~for~entire~task~using~the~enhancement~when~possible}{Performance~for~entire~task~without~enhancement}
\end(equation}
}}}

{{{
           Performance for entire task using the enhancement when possible
Speedup = -----------------------------------------------------------------
              Performance for entire taks without using the enhancement
}}}
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{{{
                  Old Execution Time
SpeedupOverall = --------------------
                  New Execution Time
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                                                                    FractionEnhanced
New Execution Time = Old Execution Time ( (1 - FractionEnhanced) + ------------------ )
                                                                    SpeedupEnhanced
This gives a new Execution time of
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or

                       Execution Time affected by Improvement
New Execution Time = -------------------------------------- + Execution Time unaffected
                            Amount of Improvement (x times)
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                                     1
SpeedupOverall = --------------------------------------------
                                           FractionEnhanced
                 (1 - FractionEnhanced) + ------------------ )
                                           SpeedupEnhanced
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}}}

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See SpeedUp

Notice that we are talking about the entire task here and that performance (speedup) is defined in terms of execution time! So we have to define the following:

This gives a new Execution time of

So we have

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AmdahlsLaw (last edited 2020-01-23 23:15:20 by scot)