Question

For a data cache with a 92% hit rate and a 2-cycle hit latency, calculate the average memory access latency. Assume that latency to memory and the cache miss penalty together is 124 cycles.

Answer 1

AMAT is 11.92ns.

Explanation:

Given,

Hit rate = 92%

Hit latency = 2 cycle

Latency to memory + miss penalty = 124 cycles

Average Memory Access Latency = ?

We know,

Average memory-access time (AMAT)  = Hit time + Miss rate x Miss penalty

So,

If hit rate is 92% then the miss rate would be 8%

Thus,

AMAT = 2 + 0.08 X 124

AMAT = 11.92ns

Therefore, AMAT is 11.92ns.