Question

2. (10 points) our storage consists only of l1 cache, l2 cache and ram. l1 cache has a total access time of 1 ns and a hit rate of 80%. l2 cache has a total access time of 20 ns and a hit rate of 15% (this is the absolute rate). ram has a total access time of 90 ns. what is the amat for this scenario?

Answer 1

The Average Memory Access Time (AMAT) for the given scenario is calculated to be 16.7 ns, using the provided hit rates and access times for L1 cache, L2 cache, and RAM.

Step-by-step explanation:

The student's question asks for the calculation of the Average Memory Access Time (AMAT) considering a system with only L1 cache, L2 cache, and RAM, each with different access times and hit rates. The formula to calculate AMAT is:

AMAT = (Hit rate for L1) * (Access time for L1) + (Miss rate for L1) * ((Hit rate for L2) * (Access time for L2) + (Miss rate for L2) * (Access time for RAM))

Substituting the given values, we get:

AMAT = (0.8 * 1 ns) + (0.2 * ((0.15 * 20 ns) + (0.85 * 90 ns)))
= (0.8 ns) + (0.2 * (3 ns + 76.5 ns))
= (0.8 ns) + (0.2 * 79.5 ns)
= (0.8 ns) + (15.9 ns)
= 16.7 ns

Therefore, the AMAT for this scenario is 16.7 ns.