一句话：指出 L5P 卸载受底层协议卸载依赖限制，提出自主 NIC 卸载以解耦底层协议。
CPU 通常将包分段、校验和等网络相关处理卸载到 NIC，以释放宝贵的 CPU 周期。然而，现有 NIC 卸载通常只适用于第 4 层及以下协议（TCP 及更低层），无法用于构建在 TCP 之上的第 5 层协议（L5P）。作者将限制归因于一种称为“卸载依赖”的缺陷：要卸载 L5P，还必须同时卸载底层第 4 层及以下协议及相关功能，包括 TCP、IP、防火墙等。这种依赖意味着需要将复杂且不断变化的底层协议实现硬连线到卸载方案中，从而阻碍创新。论文标题表明其探索自主 NIC 卸载，旨在突破该限制，但摘要未给出具体设计、实现与评估结果。
CPUs routinely offload to NICs network-related processing tasks like packet segmentation and checksum. NIC offloads are advantageous because they free valuable CPU cycles. But their applicability is typically limited to layer≤4 protocols (TCP and lower), and they are inapplicable to layer-5 protocols (L5Ps) that are built on top of TCP. This limitation is caused by a misfeature we call ”offload dependence,” which dictates that L5P offloading additionally requires offloading the underlying layer≤4 protocols and related functionality: TCP, IP, firewall, etc. The dependence of L5P offloading hinders innovation, because it implies hard-wiring the complicated, ever-changing implementation of the lower-level protocols.
DOI 原文 ·
@inproceedings{paperbot6085,
title = {Autonomous NIC offloads},
author = {Boris Pismenny and Haggai Eran and Aviad Yehezkel and Liran Liss and Adam Morrison and Dan Tsafrir},
booktitle = {ASPLOS},
year = {2021},
doi = {10.1145/3445814.3446732}
}