Rainbow：一种面向多芯片服务器的可组合一致性协议
Rainbow: A Composable Coherence Protocol for Multi-Chip Servers
AI总结：
本文提出Rainbow可组合一致性协议，通过彩色令牌计数解耦复杂性与性能，并利用稀疏目录与d-left计数布隆过滤器协同工作，使多芯片服务器平均内存延迟显著降低，性能较类HyperTransport协议提升25%-60%。
摘要：
采用多芯片模块（MCM）和/或多插槽主板是在保持芯片良率的同时提高服务器计算密度的最合适方法。本文提出了一种在复杂性和可扩展性方面适用于此类系统的新一致性协议。该方案使用两个互补的思想：（1）一种通过彩色令牌计数将复杂性与性能解耦的机制；（2）一种通过在每个芯片的最后一级缓存（D|F-LLC）和每个内存控制器（D|F-MEM）中工作的两个功能对称模块来优化性能和成本的结构。每个结构分为两部分：（2.1）第一部分由一个小的松散包含稀疏目录组成，其中仅跟踪芯片中每个内存控制器（D-MEM）最活跃共享的数据（D-LLC）；（2.2）第二部分是一个d-left计数布隆过滤器，用于存储有关已分配块的近似信息，无论是在芯片内部（F-LLC）还是在归属内存控制器中（F-MEM）。两种结构的协同工作最大限度地减少了与一致性相关的对处理器所感知的平均内存延迟的影响。我们的方案能够将类HyperTransport一致性协议的性能提高25%到60%。
英文摘要：
The use of multi-chip modules (MCM) and/or multi-socket boards is the most suitable approach to increase the computation density of servers while keep chip yield attained. This paper introduces a new coherence protocol suitable, in terms of complexity and scalability, for this class of systems. The proposal uses two complementary ideas: (1) A mechanism that dissociates complexity from performance by means of colored-token counting, (2) A construct that optimizes performance and cost by means of two functionally symmetrical modules working in the last level cache of each chip (D|F-LLC) and each memory controller (D|F-MEM). Each of these structures is divided into two parts: (2.1) The first one consists of a small loosely inclusive sparse directory where only the most actively shared data are tracked in the chip (D-LLC) from each memory controller (D-MEM) and, (2.2) The second is a d-left Counting Bloom Filter which stores approximate information about the blocks allocated, either inside the chip (F-LLC) or in the home memory controller (F-MEM). The coordinated work of both structures minimizes the coherence-related effects on the average memory latency perceived by the processor. Our proposal is able to improve on the performance of a HyperTransport-like coherence protocol by from 25%-to-60%.
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。
