[jbl]

The OP is plotting the ratio of page-aligned vs. unaligned access time against problem size. So, on the y-axis, a value of 2 means the page-aligned access took twice as long as the unaligned access.

Took me a few moments to grok the charts too, since I haven't had my coffee yet.

[jere]

Ah good explanation. The use of "vs" in a graph title makes me assume it's describing X vs Y, which is confusing.

It also helped when I realized the graph starts at 1 for working set size of 8 and the author corresponding says:

>Except for very small working sets (1-8), the unaligned version is noticeably faster