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We Have A 64 KB 4-Way Set-Associative L2 Cache That Stores Data As 16-Byte Blocks. To Fetch A Block From Main Memory, It Takes 4 Clock Cycles For The First 4 Bytes Of The Block (Latency), Then 1 Clock Cycle Per 4 Bytes For The Remaining Bytes Of The Block. What Is The Miss Penalty For The Cache (Clock Cycles)?

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Final answer:

The miss penalty for a 64 KB 4-way set-associative L2 cache that stores 16-byte blocks, with an initial latency of 4 clock cycles for the first 4 bytes and 1 clock cycle for each subsequent 4 bytes, is 7 clock cycles in total.

Step-by-step explanation:

The student has asked about the miss penalty for a 64 KB 4-way set-associative L2 cache with 16-byte blocks. To calculate the miss penalty, we need to account for the time taken to fetch a complete block of data from the main memory, which in this case, it takes 4 clock cycles for the initial latency covering the first 4 bytes and 1 clock cycle for every subsequent 4 bytes until the entire block is fetched.

Given that a block contains 16 bytes, the first 4 bytes take 4 clock cycles. The remaining 12 bytes (16 - 4) are fetched at a rate of one cycle per 4 bytes. Thus, we have 3 units of 4 bytes each, adding 3 more clock cycles to the total miss penalty (1 cycle per 4 bytes).

Thereby, the total miss penalty would be the initial latency of 4 clock cycles plus the 3 additional cycles for the remaining bytes, resulting in a total of 7 clock cycles.

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