I haven't caught up with the latest phi releases, but I'm really interested to do so. I haven't been able to find any discussion about a coherent QPI on KNL, but have found reference to OmniPath, which looks like a non-coherent large scale memory network. Is that what you were thinking of, or maybe could you post a reference?
You are right, I was misremembering. The socketed KNL does not have QPI at all, so no multisocket boards are possible. Still the socketed KNL doesn't hang-off the PCI bus as it is its own host processor and has a dedicated link with memory.
Omnipath is used to drive both the Ethernet and PCIe.
