a) How many cycles does it take to access the main memory if a cache miss has oc

Question

a) How many cycles does it take to access the main memory if a cache miss has occurred (miss penalty)

b) Estimate the MCPI of the benchmark for both processors

Hint : You need to consider both instruction and data memory

c) Estimate the BCPI (contributions due to branch) of the benchmark for both processors

d) Considering just this benchmark, which of these processors is faster? (Assume Base CPI = 1.0 for both)

Hint : Comparing the execution time

(10 points- Correctness) Performance: In this question we will compare the performance of two processors using a certain benchmark Processor L1 SizeL1 D-Cache Miss RateL1 I-Cache Miss RateL1 Hit Time P1 P2 4KB 8KB 3% 3% 6% 0.55ns 0.90ns We are also given that accesses to the main memory takes 90ns. Additionally Processor 2 has to execute 10% more dynamic instructions than Processor I. It is also seen that only 25% of the instructions access memory (ie lw and sw instructions). Profiling the code also showed us that 20% of the instructions were branch instructions. Both processors support branch prediction with 95% of the branches being predicted accurately and mis-predictions having a 1 cycle penalty.

Explanation / Answer

1) Average memory access time= Hit Time+Miss rate*Miss penalty

:Since the question does not say anything about miss penalty, I calculate as it is: .55 + .06 + .55 + .03 = 1.19ns.

Now the total number of cycles would be the teciprocal of frequency, not sure exactly the frequency is but I'll assume it to be 1.19.

You have the answer by 1/1.19

2)

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