Knights Landing mesh hop cost X- vs Y-dir

[Michael_H_3]

Hi

in "Knights Landing: Second generation Xeon Phi product" by Sodani et al. [1],
the authors state, that "One hop on mesh takes one clock in the Y direction and two clocks in the X direction" without further explanation.
As I could not find any additional sources on this topic, it only remains for me to speculate about the reasoning behind it.
Does anyone know something about this issue and may even provide some references?

Thanks in advance,
  Michael

[1]: http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7453080

[McCalpinJohn]

From the available die photos, it looks like the distance between tiles is about twice as far in the x direction as it is in the y direction.   This is reasonable enough -- the two cores on each tile are side-by-side in the x direction.