一句话：提出软件实现的惰性 TLB 一致性机制，规避跨核 IPI 开销，显著加速虚拟内存操作。
现有操作系统采用同步 TLB shootdown 维持 TLB 一致性，需要向远端核发送 IPI 并执行中断处理，给 free、页迁移等虚拟内存操作带来显著开销。LATR 提出一种基于软件的惰性 TLB 一致性机制，以惰性方式处理 TLB 失效，从而避免昂贵的 IPI 投递及相关中断处理开销。评估表明，在 2-socket 机器上 LATR 将 munmap() 延迟降低 70.8%；无需修改应用，Apache 相比 Linux 提升 59.9%，相比高度优化的 ABIS 提升 37.9%。
We propose LATR-lazy TLB coherence-a software-based TLB shootdown mechanism that can alleviate the overhead of the synchronous TLB shootdown mechanism in existing operating systems. By handling the TLB coherence in a lazy fashion, LATR can avoid expensive IPIs which are required for delivering a shootdown signal to remote cores, and the performance overhead of associated interrupt handlers. Therefore, virtual memory operations, such as free and page migration operations, can benefit significantly from LATR's mechanism. For example, LATR improves the latency of munmap() by 70.8% on a 2-socket machine, a widely used configuration in modern data centers. Real-world, performance-critical applications such as web servers can also benefit from LATR: without any application-level changes, LATR improves Apache by 59.9% compared to Linux, and by 37.9% compared to ABIS, a highly optimized, state-of-the-art TLB coherence technique.
DOI 原文 ·
@inproceedings{paperbot4255,
title = {LATR},
author = {Mohan Kumar Kumar and Steffen Maass and Sanidhya Kashyap and Ján Veselý and Zi Yan and Taesoo Kim and Abhishek Bhattacharjee and Tushar Krishna},
booktitle = {ASPLOS},
year = {2018},
doi = {10.1145/3173162.3173198}
}