I have seen and read that, at some point I just stopped bothering to respond.
I have learnt to never attribute accuracy to bombastic statements, especially those lacking sound argument. So thanks for arguing your case. However, please be less dismissive and more tolerant of another point of view (even if you experience irritation at my ignorance, as the case may be).
You may be a world class circuit designer for all that I know, while I am certainly not (I have just a computing science degree with a very basic education in this area). I am sorry if this further annoys you, but I am still not convinced by your arguments.
Where our interpretations on topology differ is that you are
convinced the L2 controller does the routing, while I
think (note the difference) the L3 controller does. Based on the disclosed data we have, I think this makes most sense.
These contrasting views make a dramatic difference on the complexity of the topology. In your case, it means connecting every L2 controller to every L3 controller (4 x 4 = 16), while in my case, it means connecting all the L3 controllers (4 x (4 - 1) / 2 = 6, plus 4 ordinary L2 to L3 connections, for a total of 10). That is a sizable difference for linking up the cores.
Any fully connected scheme does not scale. That you think your scheme does, even to 8 cores for "Zen 3" (8 x 8 = 64 links), twitches the eyebrow. That you think links are low cost (area, power, switch complexity), I find puzzling. The way you downplay this, while overplaying contrived counter-arguments and flat out dismissing contradictory evidence, weakens your argument rather than convincing me.
As
@NostaSeronx points out, there is evidence for non-uniform L3 slice latency. Your dismissal is unconvincing. The details of the methodology used to arrive at those measurements are unclear (they may include averaging and second-order effects, such as prefetching and buffering effects), so I do not read much into their magnitude.
PS. For readers confused by this discussion, here is a simple picture of the gist of it. Pick your camp.