Bringing Distributed Ordering to Heterogeneous Memory Consistency

Abstract

CORD is a novel cache-coherence protocol that brings distributed-systems techniques to tightly coupled heterogeneous processors, unlocking efficient and programmer-friendly shared memory for emerging heterogeneous workloads such as AI/ML. Cache-coherence protocols have historically enforced consistency at the source processor, inflating application latency and interconnect traffic. Central to CORD’s efficiency is its reframing of heterogeneous coherence as a distributed-systems problem: drawing on logical-timestamp algorithms for event ordering, CORD assigns consistency-tailored timestamps to write-through stores and orders them at the cache directory — near each store’s completion point at the LLC. In our evaluation, CORD approaches message-passing efficiency while incurring a fraction of the programming complexity, with negligible storage, area, and power overheads. The result is a concrete demonstration that long-standing architectural challenges in shared-memory designs can be tackled through the lens of distributed systems.

BibTeX

@article{cord-toppicks,
  author = {Yu, Yanpeng and Oswald, Nicolai and Khandelwal, Anurag},
  title = {{Bringing Distributed Ordering to Heterogeneous Memory Consistency}},
  journal = {IEEE Micro},
  month = oct,
  year = {2026}
}