my_digital_garden/4a1s/CP/PL - Aula 3.md

Ex. 1

a)

Spacial locality -(constant) proximity of memory spaces relative to a reference memory space

Logically following the multiplication process of matrices, C and A have spacial locality (while B does not, due to advancing in columns and not rows). Matrix C also has temporal locality.

b)

cache size = 25600 KB cache line/alignment= 64 B double -> 8

(64/8) = 8 elements

Estimation of misses:

• matrix C: n² / 8
• matrix B: n³
• matrix A: n³ / 8

[!info] The difference in being divided by 8 or not comes from the spacial locality of the matrix.

[!info]- Commands ran nano /proc/cpuinfo srun --partition=cpar perf cat /proc/cpuinfo

c)