Compute Express Link Memory (CXL) is a new memory architecture based on the Compute Express Link (CXL) interface, which optimizes memory access efficiency between different computing resources. CXL is an open standard high-speed interconnection interface that allows low-latency and high-bandwidth communication between computing resources such as CPUs, GPUs, memory, and storage devices.
Key features of CXL memory:
Heterogeneous computing support:
CXL memory enables CPUs and other accelerators (e.g., GPUs, FPGAs) to share the same piece of memory, eliminating the need for memory copies between different devices and greatly improving computing efficiency. This is beneficial for applications that require large-scale data processing, such as artificial intelligence and high-performance computing (HPC).
Memory Scalability:
CXL memory can expand the total memory capacity of the system by connecting external memory modules, beyond the limitations of traditional memory architectures. In this way, the system can be more flexible to respond to different workload needs.
Persistence at the memory level:
CXL can also support non-volatile memory (NVM), so that data will not be lost even in the event of a power outage. This allows CXL memory to be used to build more reliable systems, especially in applications where persistent data is required.
Unified memory space:
CXL memory supports a unified memory address space, allowing CPUs and other devices to manipulate data directly in a shared memory space without the need for complex memory management processes.
Figure: CXL Roadmap (Source: CXL Alliance)
Application Scenarios:
CXL memory is widely used in scenarios that require large amounts of data processing, such as cloud computing, data centers, high-performance computing, artificial intelligence, and machine learning. With CXL memory, the system can use memory resources more efficiently, reduce latency, and improve overall performance.
In a nutshell, CXL memory is a new technology designed to improve the memory utilization and data processing efficiency of modern computing systems, and to integrate CPUs with other computing resources more tightly through high-speed interconnect interfaces. In addition, CXL memory technology has a significant impact on the future of data centers. CXL technology supports the expansion of server memory capacity through CXL memory modules, which helps solve the problem of limited memory capacity of traditional servers, while providing higher memory bandwidth and lower access latency, thereby improving the overall performance of the data center. Through memory pooling and tiering, CXL technology helps reduce data center operating costs by reducing idle and wasted memory while allowing for more flexible resource allocation. CXL technology integrates Integrity & Data Encryption (IDE) and Trusted Execution Environment Device Interface Security Protocol (TDISP) modules to ensure the security and integrity of data transmission. CXL technology supports rack-level decomposition architecture, allowing flexible allocation and combination of memory, compute, and I/O resources to meet the needs of diverse application scenarios.
At present, CXL technology is widely supported by industry giants including hyperscale cloud service providers, system OEMs, platform and module manufacturers, chip manufacturers, and IP providers, indicating its wide application and rapid development in the data center field.
