Three enhancements with the following speed-up are proposed for a new architecture:
Enhancement A: Speedup = 30; Enhancement B: Speedup = 20; Enhancement C: Speed-up = 15;
Only one enhancement is usable at a time. Assume the enhancements can be used 25%, 35% and 10% of the time for enhancements A, B, and C respectively.
For what fraction of the reduced execution time is no enhancement is in use?
Let Te and T NEe denote execution time with enhancement and the time during enhanced execution in which no enhancements are in use, respectively. Let Toriginal and F NEoriginal stand for execution time without enhancements and the fraction of that time that cannot be enhanced. Finally, let F NEe represent the fraction of the reduced (enhanced) execution time for which no enhancement is in use. By definition: F NEe = T NEe/Te