CXL-Enabled Enhanced Memory Functions

Abstract

The arrival of the Compute Express Link (CXL) protocol is a significant milestone for the systems community. CXL provides a standardized, cache-coherent memory protocol that can be used to attach devices and memory to a system, while maintaining memory coherency with the host processor. CXL enables accelerators (e.g., graphics processing units and data processing units) to both have direct load/store access to the host memory and the ability to make their own on-device memory likewise accessible to the host central processing unit. Because CXL allows technology interposition on the memory data plane, it opens up the possibility of “pushing down” functions into the memory subsystem. In this article, we introduce the concept of enhanced memory functions (EMFs). We then describe two use cases, one prototyped using a field-programmable gate array-based intelligent memory controller platform. Finally, we show initial experimental results indicating that EMFs could present valuable solutions to problems that are difficult to solve within existing computer architectures.