Sponsor Editorial

This one is about a question that comes up in every heterogeneous SoC design: which traffic goes on the coherent fabric, which goes on the non-coherent fabric, and how do you bridge between the two? The answer isn't a preference. It's an architectural constraint with real silicon cost on both sides of the decision.

Here's what the paper covers:
🔹 Why putting I/O traffic on a coherent fabric wastes directory entries, snoop bandwidth, and link capacity at scale 
🔹 Why software-managed coherency breaks at modern agent counts — and the failure mode when it does
 🔹 The spectrum from fully coherent (RN-F) to I/O coherent (RN-I) to non-coherent, and how to assign each block correctly 
🔹 Measured numbers: 53% vs 82% memory bandwidth utilization, 36 ns vs 137 ns inter-core latency — what coherency actually costs 
🔹 How Proxy Cache bridges the two fabrics without forcing non-coherent IP to implement CHI
 🔹 How the partition extends off-die: PCIe for non-coherent, CXL for coherent, UCIe die-to-die on C-NOC for chiplets 
🔹 Functional safety requirements — and where SignatureIP's roadmap sits today