The Compute Express Link (CXL) is an open industry-standard interconnect between processors and devices such as accelerators, memory buffers, smart network interfaces, persistent memory, and solid-state drives. CXL offers coherency and memory semantics with bandwidth that scales with PCIe bandwidth while achieving significantly lower latency than PCIe. All major CPU vendors, device vendors, and datacenter operators have adopted CXL as a common standard. This enables an inter-operable ecosystem that supports key computing use cases including highly efficient accelerators, server memory bandwidth and capacity expansion, multi-server resource pooling and sharing, and efficient peer-to-peer communication. This survey provides an introduction to CXL covering the standards CXL 1.0, CXL 2.0, and CXL 3.0. We further survey CXL implementations, discuss CXL's impact on the datacenter landscape, and future directions.

翻译：计算快速链接（CXL）是一种开放行业标准互连技术，用于连接处理器与加速器、内存缓冲器、智能网络接口、持久内存及固态硬盘等设备。CXL提供缓存一致性及内存语义，其带宽随PCIe带宽扩展，同时延迟显著低于PCIe。所有主要CPU厂商、设备制造商及数据中心运营商已采用CXL作为通用标准。这催生了支持高效加速器、服务器内存带宽与容量扩展、多服务器资源池化与共享、以及高效点对点通信等关键计算用例的互操作生态系统。本综述介绍CXL技术，涵盖CXL 1.0、CXL 2.0和CXL 3.0标准，并进一步调研CXL实现方案，探讨CXL对数据中心格局的影响及未来发展方向。