An Evaluation of Delayed Consistency Protocols

延迟一致性协议的评估

• 批准号: 9115725
• 负责人: Michel Dubois
• 金额: $ 13.65万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-15 至 1994-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9115725&HistoricalAwards=false
• 关键词: Evaluation; Delayed; Consistency; Protocols

This research involves the experimental analysis of delayed consistency in large-scale cache-based multiprocessors including its effects on false sharing and latency tolerance. False sharing refers to the read/write sharing of cache blocks in the absence of data sharing in a parallel computation. Latency tolerance refers to the reduction of the average latency of shared-memory accesses by overlapping them with computation. Delayed consistency takes advantage of weak ordering in cache-based systems. The sending of cache invalidation can be delayed, in which case they can be overlapped with processor accesses to the cache. Additionally, both the sending and receiving of invalidations can be delayed, in which case false sharing effects are reduced by increasing the time during which cached blocks remain accessible by each local processor. The quantitative effects of delaying consistency and its variants will be evaluated through execution-driven simulation of parallel benchmark programs, including nine parallel numerical as well as non-numerical algorithms and thirteen Fortran programs contained in the Perfect Club Benchmark suite, parallelized using an Alliant 2800 compiler. Emphasis will be on the effects of block size, cache size, and granularity of parallelism. Statistics will be collected not only on miss rates, but also on memory traffic, on memory access latencies and on total execution times.

本研究涉及大规模基于缓存的多处理器延迟一致性的实验分析，包括其对错误共享和延迟容忍的影响。虚假共享是指在并行计算中，在没有数据共享的情况下，缓存块的读写共享。延迟容忍是指通过计算重叠共享内存访问来减少平均延迟。延迟一致性利用了基于缓存的系统中的弱排序。缓存失效的发送可以延迟，在这种情况下，它们可以与处理器对缓存的访问重叠。此外，失效的发送和接收都可以延迟，在这种情况下，通过增加每个本地处理器仍然可以访问缓存块的时间，可以减少错误共享效果。延迟一致性及其变体的定量影响将通过并行基准程序的执行驱动模拟来评估，包括9个并行数值和非数值算法以及包含在完美俱乐部基准套件中的13个Fortran程序，使用Alliant 2800编译器并行化。重点将放在块大小、缓存大小和并行度粒度的影响上。统计信息将不仅收集失分率，还收集内存流量、内存访问延迟和总执行时间。