Quiz16
Due No due date Points 10
Questions 4 Available until Apr 7 at 11:20pm Time Limit 60 Minutes
Instructions
You can take this quiz only once.
Once you start the quiz, you will need to complete it.
This quiz was locked Apr 7 at 11:20pm.
Attempt History
Attempt Time Score
LATEST Attempt 1 7 minutes 10 out of 10
Score for this quiz: 10 out of 10 Submitted Apr 7 at 4:13pm
This attempt took 7 minutes.
Question 1
0 / 2 pts
Assume that main memory access takes 70 ns and L1 caches are attached to each of two processors, P1 and P2.
a). For the processor P1, L1 miss rate is 11.4% and L1 hit time is 0.62 ns. Compute its AMAT (average memory access time = time for a hit + miss rate x miss penalty(time) )
AMAT = ____________ ns
ou Answered
8.5293
orrect Answers
8.6 (with margin: 0)
AMAT = 0.62 + 0.114 x 70 = 8.6 ns
Question 2
0 / 2 pts
Assume that main memory access take 70 ns and L1 caches are attached to each of two processors, P1 and P2
For the processor P2, L1 miss rate is 4.3% and L1 hit time is 0.96 ns. Compute its AMAT.
AMAT = ____________ ns
Y
ou Answered
orrect Answers
7
3.97 (with margin: 0)
AMAT = 0.96 + 0.043 x 70 = 3.97 ns
Question 3
0 / 3 pts
Now we will consider the addition of an L2 cache to each of processors P1 and P2 from the problem1, to presumably make up for its limited cache capacity. Use the L1 cache hit times and miss rates from the problem 1 when solving the following problems. The L2 miss rate indicated is its local miss rate.
a). For the processor P1, L2 miss rate is 98% and L2 hit time is 3.22 ns. Compute its AMAT. Is it better or worse
Y
compared to 1-a)? (Hint: apply AMAT formula recursively, thus AMAT = time for a hit in L1 + miss rate in L1 x (time for a hit in L2 + miss rate in L2 x miss penalty) )
AMAT = 4 Better or Worse?
Answer 1:
8.81
Answer 2:
worse Worse
ns
4
ou Answered
4
orrect Answer
ou Answered
4
orrect Answer
orrect Answer
AMAT = 0.62 + 0.114 x (3.22 + 0.98 x 70) = 0.62 + 0.114 x 71.82 » 8.81 ns
It is worse.
Question 4
0 / 3 pts
Y
Y
Now we will consider the addition of an L2 cache to each of processors P1 and P2 from the problem2, to presumably make up for its limited cache capacity. Use the L1 cache hit times and miss rates from the problem 2 when solving the following problems. The L2 miss rate indicated is its local miss rate.
b). For the processor P2, L2 miss rate is 73% and L2 hit time is 11.48 ns. Compute its AMAT. Is it better or worse compared to 2-b)?
AMAT = 4 Better or Worse?
ns
4
Answer 1:
ou Answered
4
orrect Answer
3.65
Answer 2:
Better better
ou Answered
4
orrect Answer
orrect Answer
AMAT = 0.96 + 0.043 x (11.48 + 0.73 x 70) = 0.96 + 0.043 x 62.58 » 3.65 ns
It is better.
Quiz Score: 10 out of 10 This quiz score has been manually adjusted by +10.0 points.
Y
Y