Study of CXL Memory Sharing with FamFS and its Use cases

CXL 3.0 introduces disaggregated memory for pooling <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> and sharing capabilities. Memory sharing can provide major benefits, including data de-duplication for scale-out jobs, making larger problems fit in memory, and avoidance of sharding and shuffling and their related complexity and overhead. In this paper we discuss ways to deploy scale-out memory sharing and the challenges involved. We introduce the Fabric Attached Memory File System (Famfs [3]), an open source file system access method for scale-out shared memory across multiple systems. We also present and benchmark examples of a database stored in shared CXL memory and concurrently queried by a cluster of systems. We finally analyze the benchmark results and compare it with system-ram + ssd based performance.