Differences between revisions 4 and 31 (spanning 27 versions)
Revision 4 as of 2004-01-25 18:27:41
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Editor: yakko
Comment:
Revision 31 as of 2008-10-24 02:24:20
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Editor: 209-142-131-35
Comment:
Deletions are marked like this. Additions are marked like this.
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{{{
           Performance for entire task using the enhancement when possible
Speedup = -----------------------------------------------------------------
              Performance for entire taks without using the enhancement
}}}
<<latex(Speedup=Performance using enhancement when possiblePerformance without enhancement)>>
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{{{
                  Old Execution Time
SpeedupOverall = --------------------
                  New Execution Time
<<latex(SpeedupOverall=Old Execution TimeNew Execution Time)>> (1)
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                                                                    FractionEnhanced
New Execution Time = Old Execution Time ( (1 - FractionEnhanced) + ------------------ )
                                                                    SpeedupEnhanced
This gives a new Execution time of

<<latex(New Exec Time=Old Exec Time(1FractionEnhanced+FractionEnhancedSpeedupEnhanced))>>
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                                     1
SpeedupOverall = --------------------------------------------
                                           FractionEnhanced
                 (1 - FractionEnhanced) + ------------------ )
                                           SpeedupEnhanced
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}}} <<latex(SpeedupOverall=(11FractionEnhanced+FractionEnhancedSpeedupEnhanced))>>

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<<latex(Speedup=Performance using enhancement when possiblePerformance without 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:

<<latex(SpeedupOverall=Old Execution TimeNew Execution Time)>> (1)

This gives a new Execution time of

<<latex(New Exec Time=Old Exec Time(1FractionEnhanced+FractionEnhancedSpeedupEnhanced))>>

So we have

<<latex(SpeedupOverall=(11FractionEnhanced+FractionEnhancedSpeedupEnhanced))>>

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AmdahlsLaw (last edited 2020-01-23 23:15:20 by 68)