Question

An enhancement to a computer accelerates some mode of execution by a factor of 10. The enhanced mode is used 50% of the time, measured as a percentage of the execution time when the enhanced mode is in use. Recall that Amdahl's Law depends on the fraction of the original unenhanced execution time that could make use of enhanced mode. Thus the 50% measurement cannot be used directly to compute speedup with Amdahl's Law. I What is the speedup obtained from fast mode? I What percentage of the original execution time has been converted to fast mode?

Answer 1

Answer:

The answer is "5.5 and 90.90%"

Explanation:

For point 1:

To calculate the speed from fast mode, its run time without enhancement should be worked out. Designers are aware of which two selves are implicated throughout the accelerated project planning: the empty ($50 \%$) and the increased stages ($50 \%$).

Although not enhanced, this would take almost as long ($50 \%$) and for the combine to give phase; even so, the increased phase would've been 10 times longer, as well as $500 \%$. Thus the corresponding total speed without enhancement is $=50\% + 500\% = 550\%.$

Its overall speed is:

$=\frac{\text{Accelerated runtime}}{ \text{accelerated runtime}} = \frac{550 \%}{ 100 \%}= 5.5$

For point 2:

We re-connect these figures in Amdahl's Law throughout order to identify how long it would take for both the initial implementation:

$\text{Vectorized fraction}= \frac{\text{Overall velocity}\times \text{Accelerated acceleration}-\text{Accelerated acceleration}}{\text{Overall acceleration} \times \text{Accelerated acceleration}-\text{Overall acceleration}}$

                              $= \frac{5.5 \times 10 -10 }{ 5.5 \times 10 - 5.5}\\\\=\frac{45}{49.5}\\\\=0.9090\\\\=90.90\%$