Assume that for a certain processor, a read request takes 50 ns on a cache…

2022

Assume that for a certain processor, a read request takes 50 ns on a cache miss and 5 ns on a cache hit. Suppose while running a program, it was observed that 80% of the processor’s read requests result in cache hit. The average read access time in nanoseconds is —

  1. A.

    10

  2. B.

    14

  3. C.

    4

  4. D.

    12

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Show answer & explanation

Correct answer: B

Average time = (hit_fraction × hit_time) + (miss_fraction × miss_time) Hit fraction = 0.8, Miss fraction = 0.2 Average = 0.8×5 + 0.2×50 = 4 + 10 = 14 ns

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