SMT: Software-Defined Memory Tiering for Heterogeneous Computing Systems With CXL Memory Expander

The rapid development of data-intensive technologies has driven an increasing demand for new architectural solutions with scalable, composable, and coherent computing environments. Compute Express Link (CXL), an open-standard interconnect protocol, overcomes architectural limitations by efficiently expanding memory capacity and bandwidth. In this work, we propose a power-efficient and cost-effective solution consisting of CXL-attached memory hardware and a software suite. The memory module hardware integrated with double-data-rate (DDR) dynamic random access memory and a CXL controller expands bandwidth by dozens of gigabytes per second and increases memory capacity by a few terabytes. Our software suite, scalable memory development kit, inherits and expands the traditional memory management architecture of existing Linux systems. We proved the functionality of the proposed solution by integrating renowned data centers and computing-intensive applications. The proposed CXL solution improved throughput for in-memory database and artificial intelligence applications by 1.5-fold and 1.99-fold, respectively, compared with the conventional DDR-only memory system.