(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Suppose your data cache has 30 lines and each line can hold 10 doubles. You are performing a matrix-matrix multiplication (C=C+A*B) with square matrices of size 1000 and 10 respectively. Assume data caches are only used to cache matrix elements which are doubles. The cache replacement rule is least recently used first. One-dimensional arrays are used to represent matrices with the row major order.

(a). When matrix-matrix multiplication is performed using the simple triple-loop algorithm, there are 6 versions of the algorithm (ijk, ikj, jik, jki, kij, kji). Calculate the number of cache misses for each element in each matrix for each version of the algorithm when the sizes of the matrices are 1000 and 10 respectively.

2. Relevant equations

N/A

3. The attempt at a solution

I'm confused about the actual matrix multiplication. From the problem I'm getting matrix A: 1000x1000 and matrix b: 10x10. How can these two be multiplied? The number of columns and rows do not match up between them. Am I misreading the problem?

After the above is clarified I understand that not just one element of the matrix is transferred to the cache but how many are? since matrix A is 1000x1000 is the whole first row a0,0 to a0, 999 transfered into the cache when a0,0 is brought in? Or are just 10 element blocks brought into the cache? If only 10 are brought in at a time are they brought in sequentially or is part of matrix b brought in too?

Sorry for the overload of questions, I just don't understand the problem and can't progress without understanding it.

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# Homework Help: Calculating cache misses

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