Translation lookaside buffer (TLB) is critical to modern multi-level memory systems’ performance. However, due to the limited size of the TLB itself, its address coverage is limited. Adopting a two-level exclusive TLB hierarchy can increase the coverage [M. Swanson, L. Stoller and J. Carter, Increasing TLB reach using superpages backed by shadow memory, 25th Annual Int. Symp. Computer Architecture (1998); H.P. Chang, T. Heo, J. Jeong and J. Huh Hybrid TLB coalescing: Improving TLB translation coverage under diverse fragmented memory allocations, ACM SIGARCH Comput. Arch. News 45 (2017) 444–456] to improve memory performance. However, after analyzing the existing two-level exclusive TLBs, we find that a large number of “dead” entries (they will have no further use) exist in the last-level TLB (LLT) for a long time, which occupy much cache space and result in low TLB hit-rate. Based on this observation, we first propose exploiting temporal and spatial locality to predict and identify dead entries in the exclusive LLT and remove them as soon as possible to leave room for more valid data to increase the TLB hit rates. Extensive experiments show that our method increases the average hit rate by 8.67%, to a maximum of 19.95%, and reduces total latency by an average of 9.82%, up to 24.41%.

中文翻译：

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LPE：大覆盖的独家 TLB 中基于位置的死预测

翻译后备缓冲区 (TLB) 对现代多级内存系统的性能至关重要。但是，由于 TLB 本身的大小有限，它的地址覆盖范围是有限的。采用两级排他 TLB 层次结构可以增加覆盖率 [M. Swanson、L. Stoller 和 J. Carter，使用影子内存支持的超级页面增加 TLB 范围，第 25 届年度诠释。症状。计算机架构(1998); HP Chang、T. Heo、J. Jeong 和 J. Huh 混合 TLB 合并：提高不同碎片内存分配下的 TLB 翻译覆盖率，ACM SIGARCH 计算机。拱。消息 45(2017) 444–456] 以提高内存性能。但是，通过对现有的二级独占TLB的分析，我们发现在最后一级TLB（LLT）中长期存在大量的“死”条目（它们将不再使用），占用了大量的缓存。空间并导致低 TLB 命中率。基于这一观察，我们首先建议利用时间和空间局部性来预测和识别排他 LLT 中的死条目并尽快将其删除，以便为更多有效数据留出空间以提高 TLB 命中率。大量实验表明，我们的方法将平均命中率提高了 8.67%，最高可达 19.95%，将总延迟平均降低了 9.82%，最高可达 24.41%。