Design Tradeoffs in CXL-Based Memory Pools for Public Cloud Platforms

Dynamic random-access memory (DRAM) is a key driver of performance and cost in public cloud servers. At the same time, a significant amount of DRAM is underutilized due to fragmented use across servers. Emerging interconnects such as Compute Express Link (CXL) offers a path toward improving utilization through memory pooling. However, the design space of CXL-based memory systems is large, with key questions around the size, reach, and topology of the memory pool. At the same time, using pools require navigating complex design constraints around performance, virtualization, and management. This article discusses why cloud providers should deploy CXL memory pools, key design constraints, and observations in designing toward practical deployment. We identify configuration examples with significant positive return of investment.