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

Differences between revisions 7 and 31 (spanning 24 versions)

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

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:

<<latex( $S p e e d u p O v e r a l l = \frac{O l d E x e c u t i o n T i m e}{N e w E x e c u t i o n T i m e}$ )>> (1)

This gives a new Execution time of

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

So we have

<<latex( $S p e e d u p O v e r a l l = (\frac{1}{1 - F r a c t i o n E n h a n c e d + \frac{F r a c t i o n E n h a n c e d}{S p e e d u p E n h a n c e d}})$ )>>

Back to ComputerTerms

-  ⇤ ← Revision 7 as of 2005-06-27 22:15:58 → 
  Size: 1569
  Editor: yakko
  Comment:
+   ← Revision 31 as of 2008-10-24 02:24:20 → ⇥
  Size: 720
  Editor: 209-142-131-35
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 3:
-{{{#!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
}}}
+<<latex( $S p e e d u p = \frac{P e r f o r m a n c e u s i n g e n h a n c e m e n t w h e n p o s s i b l e}{P e r f o r m a n c e w i t h o u t e n h a n c e m e n t}$ )>>
-Line 19:
+Line 9:
-{{{
                  Old Execution Time
SpeedupOverall = --------------------
                  New Execution Time
+<<latex( $S p e e d u p O v e r a l l = \frac{O l d E x e c u t i o n T i m e}{N e w E x e c u t i o n T i m e}$ )>> (1)
-Line 24:
+Line 11:
-                                                                    FractionEnhanced
New Execution Time = Old Execution Time ( (1 - FractionEnhanced) + ------------------ )
                                                                    SpeedupEnhanced
+This gives a new Execution time of
-Line 28:
+Line 13:
-or

                       Execution Time affected by Improvement
New Execution Time =   --------------------------------------  + Execution Time unaffected
                            Amount of Improvement (x times)
+<<latex( $N e w E x e c T i m e = O l d E x e c T i m e (1 - F r a c t i o n E n h a n c e d + \frac{F r a c t i o n E n h a n c e d}{S p e e d u p E n h a n c e d})$ )>>
-Line 35:
+Line 16:
-
SpeedupOverall = --------------------------------------------
                                           FractionEnhanced
                 (1 - FractionEnhanced) + ------------------ )
                                           SpeedupEnhanced
-Line 41:
+Line 17:
-}}}
+<<latex( $S p e e d u p O v e r a l l = (\frac{1}{1 - F r a c t i o n E n h a n c e d + \frac{F r a c t i o n E n h a n c e d}{S p e e d u p E n h a n c e d}})$ )>>