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Andy Neil
08/01/05 00:00
Read: 1666 times

#98544 - You need a Profiler
Responding to: Jan Waclawek's previous message
Jan Waclawek said:
It should be possible to decompose the (structured) program into smaller blocks (in a tree form) and determine the worst-case execution time of it ... Will this be useful?

I doubt it.

There is absolutely no guarantee whatsoever that any particular sequence of source statements will generate any specific set of machine instructions; therefore it is impossible to predict execution timings from 'C' source code.

This is the reason why writing delay loops in 'C' is fundamentally flawed.

However, automated tools do exist to examine the compiler's output and produce performance reports - called "Profilers" or similar.
Although not automated, you could use the Performance Analyser in Keil's simulator/debugger to do this manually.

List of 18 messages in thread
Counting cycles... possible in C?      Jan Waclawek      07/28/05 01:03      
   You need a Profiler      Andy Neil      08/01/05 00:00      
      The compiler knows      Jan Waclawek      08/01/05 03:21      
         Source code useless      Andy Neil      08/01/05 04:50      
         That's why you need Assembler!      Andy Neil      08/01/05 04:56      
            nohohoho      Jan Waclawek      08/01/05 05:12      
               Speed is not everything!      Andy Neil      08/01/05 05:54      
   Cycles vary?      James Krushlucki      08/01/05 01:37      
      I know      Jan Waclawek      08/01/05 03:23      
   absolutely, but what good does it do      Erik Malund      08/01/05 06:27      
      other way round      Jan Waclawek      08/01/05 07:10      
         Yes, the things posted apply in this cas      Erik Malund      08/01/05 07:23      
            exactly for this reason      Jan Waclawek      08/01/05 08:29      
               how can you automate that it is small en      Erik Malund      08/01/05 08:35      
   Use Microsoft Excel      Aubrey Kagan      08/01/05 18:04      
      excel and conditional branches ?      Erik Malund      08/02/05 05:53      
         That's why      Aubrey Kagan      08/02/05 07:13      
            That makes absolutotally no difference,      Erik Malund      08/02/05 07:23      

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