A paging system TLB takes 10 ns, main memory takes 50 ns. What is the…
2008
A paging system TLB takes 10 ns, main memory takes 50 ns. What is the effective memory access time if TLB hit ratio is 90%?
- A.
54
- B.
60
- C.
65
- D.
75
Attempted by 101 students.
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Correct answer: C
To calculate the effective memory access time, consider the TLB hit and miss scenarios.
Step 1: TLB hit time = TLB access time + memory access time = 10 ns + 50 ns = 60 ns.
Step 2: TLB miss time = TLB access time + first memory access + second memory access = 10 ns + 50 ns + 50 ns = 110 ns.
Step 3: Effective access time = (hit ratio × hit time) + (miss ratio × miss time) = (0.9 × 60) + (0.1 × 110) = 54 + 11 = 65 ns.
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