(2) Assume that we make an enhancement to a computer that improves some mode of execution by a factor of 10. Enhanced mode is used 50% of the time, measured as a fraction of the execution time when the enhanced mode is in use. Recall that Amdahl's law depends on the fraction of the original unenhanced time that could make use of the enhanced mode. Thus we cannot directly use the 50% measurement to compute speedup with Amdahl's law.

(a) What is the speedup we have obtained from fast mode?
(b) What percentage of the original execution time has been converted to fast mode?


Detailed answers to tough
homework problems