Reference no: EM133247606

Assignment:

Problem

Three Improvements are considered to a base machine with a Load/Store ISA (similar to MIPS) and in which floating-point arithmetic instructions are implemented by software handlers. The first improvement is to add more first-level data cache to speed up the execution of Loads and Stores. Loads and Stores can both be speeded up by a factor 5 over the base machine with the new cache. The second improvement is to add hardware floating-point arithmetic units to speed up floating-point arithmetic instructions. It is estimated that the time taken by each floating-point instruction can be reduced by a factor 3 over the base machine. The third improvement is to add a Store buffer between the processor and its first level cache. The Store buffer eliminates the overhead of Stores in all cases.

It is estimated that, the same amount of hardware and cost is incurred by all three enhancements The fractions of execution time spent in floating-point, Load and Store instructions in the base machine are 25%, 30% and 10%, respectively. The executions of these three types of instructions are non-overlapping in time.

a. Using Amdahl's speedup, compute the speedup of each enhancement over the base machine. Which enhancement is the most beneficial to implement first?

b. Given the first enhancement has been implemented, which enhancement of the two remaining enhancements should be done next? (Here you should compute anew the Amdahl's speedups for the new machine in a.)

c. Finally, compute the speedup in the machine in b. after the last feature is added to the machine in b?