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

Differences between revisions 1 and 20 (spanning 19 versions)

$$Speedup = \frac{Performance~using~enhancement~when~possible}{Performance~without~enhancement}$$

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:

(1) latex2($$SpeedupOverall = \frac{Old~Execution~Time}{New~Execution~Time}$$)

$$New~Exec~Time = Old~Exec~Time \left( 1 - FractionEnhanced + \frac{FractionEnhanced}{SpeedupEnhanced}\right)$$

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

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-  ⇤ ← Revision 1 as of 2004-01-25 18:20:24 → 
  Size: 301
  Editor: yakko
  Comment:
+   ← Revision 20 as of 2005-06-27 22:27:19 → ⇥
  Size: 1103
  Editor: yakko
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 3:
-{{{
           Performance for entire task using the enhancement when possible
Speedup = -----------------------------------------------------------------
              Performance for entire taks without using the enhancement
+{{{#!latex2
$$Speedup = \frac{Performance~using~enhancement~when~possible}{Performance~without~enhancement}$$
-Line 11:
+Line 9:
+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:

(1) [[latex2($$SpeedupOverall = \frac{Old~Execution~Time}{New~Execution~Time}$$)]]

{{{#!latex2
$$New~Exec~Time = Old~Exec~Time \left( 1 - FractionEnhanced + \frac{FractionEnhanced}{SpeedupEnhanced}\right)$$
}}}

{{{
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

}}}