利用支持CXL的空闲I/O带宽回收突破内存带宽墙
Pushing the Memory Bandwidth Wall with CXL-enabled Idle I/O Bandwidth Harvesting
AI总结：
针对服务器CPU单核内存带宽不足、片外带宽因内存与I/O拆分导致利用率低的问题，提出软件支持的架构技术SURGE，借助CXL复用空闲I/O带宽，最高可将内存密集型负载加速1.3倍。
摘要：
服务器级CPU核心数量的持续增长对内存系统提出了更高要求，而内存系统受限于有限的片外引脚与数据传输速率可扩展性。因此高端处理器的单核内存带宽通常更低，不利于内存密集型工作负载运行。我们提出通过提升CPU有限引脚的利用率来缓解该问题。在典型CPU设计流程中，可用引脚被分配给内存和I/O流量，二者各占片外总带宽的约一半。因此除非内存与I/O同时处于高负载状态，否则这种带宽拆分将导致宝贵的片外带宽资源利用率不足。理想架构应实现I/O与内存带宽的可互换性，允许以各工作负载所需的形式使用聚合片外带宽。本研究提出SURGE，这是一种软件支持的架构技术，通过回收空闲I/O带宽资源提升可用内存带宽。SURGE借助CXL等通用互连技术的能力，在同一处理器接口上动态复用内存与I/O流量。我们验证表明，经SURGE增强的架构可在带宽受限服务器上将内存密集型工作负载的运行速度最高提升1.3倍。
英文摘要：
The continual increase of cores on server-grade CPUs raises demands on memory systems, which are constrained by limited off-chip pin and data transfer rate scalability. As a result, high-end processors typically feature lower memory bandwidth per core, at the detriment of memory-intensive workloads. We propose alleviating this challenge by improving the utility of the CPU's limited pins. In a typical CPU design process, the available pins are apportioned between memory and I/O traffic, each accounting for about half of the total off-chip bandwidth availability. Consequently, unless both memory and I/O are simultaneously highly utilized, such fragmentation leads to underutilization of the valuable off-chip bandwidth resources. An ideal architecture would offer I/O and memory bandwidth fungibility, allowing use of the aggregate off-chip bandwidth in the form required by each workload. In this work, we introduce SURGE, a software-supported architectural technique that boosts memory bandwidth availability by salvaging idle I/O bandwidth resources. SURGE leverages the capability of versatile interconnect technologies like CXL to dynamically multiplex memory and I/O traffic over the same processor interface. We demonstrate that SURGE-enhanced architectures can accelerate memory-intensive workloads on bandwidth-constrained servers by up to 1.3x.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
