Overcoming the Memory Wall with CXL-Enabled SSDs

Abstract

This paper investigates the feasibility of using inexpensive flash memory on new interconnect technologies such as CXL (Compute Express Link) to overcome the memory wall. We explore the design space of a CXL-enabled flash device and show that techniques such as caching and prefetching can help mitigate the concerns regarding flash memory’s performance and lifetime. We demonstrate using real-world application traces that these techniques enable the CXL device to have an estimated lifetime of at least 3.1 years and serve 68–91% of the memory requests under a microsecond. We analyze the limitations of existing techniques and suggest system-level changes to achieve a DRAM-level performance using flash. © 2023 by The USENIX Association All Rights Reserved.