This is a simple memory benchmark; see, e.g., "Empirical Evaluation of the CRAY-T3D: A Compiler Perspective" from ISCA 1995. The membench C code basically times

for array A of length L from 4KB to 8MB by 2x
  for stride s  from 4 bytes to L/2 by 2x
    time the following loop
    for i = 0 to L by s
      load A[i]

The raw times can be plotted as a set of lines or as a heat map (I find the latter easier to process visually).