Diff for "AmdahlsLaw" - Dr. A's Wiki

Differences between revisions 6 and 24 (spanning 18 versions)

latex2( $S p e e d u p = \frac{P e r f o r m a n c e u s i n g e n h a n c e m e n t w h e n p o s s i b l e}{P e r f o r m a n c e w i t h o u t e n h a n c e m e n t}$ ) }}}

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:

latex2( $S p e e d u p O v e r a l l = \frac{O l d E x e c u t i o n T i m e}{N e w E x e c u t i o n T i m e}$ )

This gives a new Execution time of

latex2( $N e w E x e c T i m e = O l d E x e c T i m e (1 - F r a c t i o n E n h a n c e d + \frac{F r a c t i o n E n h a n c e d}{S p e e d u p E n h a n c e d})$ )

So we have latex2($$SpeedupOverall=\frac{1}{1-FractionEnhanced + \frac{FractionEnhanced}{SpeedupEnhanced}})

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-  ⇤ ← Revision 6 as of 2004-02-17 23:44:44 → 
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  Editor: yakko
  Comment:
+   ← Revision 24 as of 2005-06-28 01:18:43 → ⇥
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-Deletions 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
+[[latex2( $S p e e d u p = \frac{P e r f o r m a n c e u s i n g e n h a n c e m e n t w h e n p o s s i b l e}{P e r f o r m a n c e w i t h o u t e n h a n c e m e n t}$ )]]
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-{{{
                  Old Execution Time
SpeedupOverall = --------------------
                  New Execution Time
+[[latex2( $S p e e d u p O v e r a l l = \frac{O l d E x e c u t i o n T i m e}{N e w E x e c u t i o n T i m e}$ )]]
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+Line 12:
-                                                                    FractionEnhanced
New Execution Time = Old Execution Time ( (1 - FractionEnhanced) + ------------------ )
                                                                    SpeedupEnhanced
+This gives a new Execution time of
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+Line 14:
-or

                       Execution Time affected by Improvement
New Execution Time =   --------------------------------------  + Execution Time unaffected
                            Amount of Improvement (x times)
+[[latex2( $N e w E x e c T i m e = O l d E x e c T i m e (1 - F r a c t i o n E n h a n c e d + \frac{F r a c t i o n E n h a n c e d}{S p e e d u p E n h a n c e d})$ )]]
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+Line 17:
-
SpeedupOverall = --------------------------------------------
                                           FractionEnhanced
                 (1 - FractionEnhanced) + ------------------ )
                                           SpeedupEnhanced

}}}
+[[latex2($$SpeedupOverall=\frac{1}{1-FractionEnhanced + \frac{FractionEnhanced}{SpeedupEnhanced}})]]