Differences between revisions 5 and 7 (spanning 2 versions)
Revision 5 as of 2004-01-25 18:28:11
Size: 1157
Editor: yakko
Comment:
Revision 7 as of 2005-06-27 22:15:58
Size: 1569
Editor: yakko
Comment:
Deletions are marked like this. Additions are marked like this.
Line 2: Line 2:

{{{#!latex
\begin{equation}
   Speedup = \frac{Performance~for~entire~task~using~the~enhancement~when~possible}{Performance~for~entire~task~without~enhancement}
\end(equation}
}}}
Line 22: Line 28:
or

                       Execution Time affected by Improvement
New Execution Time = -------------------------------------- + Execution Time unaffected
                            Amount of Improvement (x times)

Back to ComputerTerms

\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

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:

                  Old Execution Time
SpeedupOverall = --------------------
                  New Execution Time

                                                                    FractionEnhanced
New Execution Time = Old Execution Time ( (1 - FractionEnhanced) + ------------------ )
                                                                    SpeedupEnhanced

or

                       Execution Time affected by Improvement
New Execution Time =   --------------------------------------  + Execution Time unaffected
                            Amount of Improvement (x times) 

So we have
                                     1
SpeedupOverall = --------------------------------------------
                                           FractionEnhanced
                 (1 - FractionEnhanced) + ------------------ )
                                           SpeedupEnhanced

Back to ComputerTerms

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