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

Differences between revisions 9 and 32 (spanning 23 versions)

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

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:

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

This gives a new Execution time of

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

So we have

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

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-  ⇤ ← Revision 9 as of 2005-06-27 22:17:41 → 
  Size: 1572
  Editor: yakko
  Comment:
+   ← Revision 32 as of 2020-01-23 23:15:20 → ⇥
  Size: 676
  Editor: 68
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
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-{{{#!latex2
 $S p e e d u p = \frac{P e r f o r m a n c e f o r e n t i r e t a s k u s i n g t h e e n h a n c e m e n t w h e n p o s s i b l e}{P e r f o r m a n c e f o r e n t i r e t a s k w i t h o u t e n h a n c e m e n t}$ 
}}}


{{{
           Performance for entire task using the enhancement when possible
Speedup = -----------------------------------------------------------------
              Performance for entire taks without using the enhancement
}}}
+ $S p e e d u p = \frac{P e r f o r m a n c e u s i n g e n h a n c e m e n t w h e n p o s s i b l e}{P e r f o r m a n c e w i t h o u t e n h a n c e m e n t}$
-Line 20:
+Line 9:
-{{{
                  Old Execution Time
SpeedupOverall = --------------------
                  New Execution Time
+ $S p e e d u p O v e r a l l = \frac{O l d E x e c u t i o n T i m e}{N e w E x e c u t i o n T i m e}$
-Line 25:
+Line 11:
-                                                                    FractionEnhanced
New Execution Time = Old Execution Time ( (1 - FractionEnhanced) + ------------------ )
                                                                    SpeedupEnhanced
+This gives a new Execution time of
-Line 29:
+Line 13:
-or

                       Execution Time affected by Improvement
New Execution Time =   --------------------------------------  + Execution Time unaffected
                            Amount of Improvement (x times)
+ $N e w E x e c T i m e = O l d E x e c T i m e (1 - F r a c t i o n E n h a n c e d + \frac{F r a c t i o n E n h a n c e d}{S p e e d u p E n h a n c e d})$
-Line 36:
+Line 16:
-
SpeedupOverall = --------------------------------------------
                                           FractionEnhanced
                 (1 - FractionEnhanced) + ------------------ )
                                           SpeedupEnhanced
-Line 42:
+Line 17:
-}}}
+ $S p e e d u p O v e r a l l = (\frac{1}{1 - F r a c t i o n E n h a n c e d + \frac{F r a c t i o n E n h a n c e d}{S p e e d u p E n h a n c e d}})$