Justitia: Software Multi-Tenancy in Hardware Kernel-Bypass Networks


Yiwen Zhang, University of Michigan; Yue Tan, University of Michigan and Princeton University; Brent Stephens, University of Illinois at Chicago; Mosharaf Chowdhury, University of Michigan


Kernel-bypass networking (KBN) is becoming the new norm in modern datacenters. While hardware-based KBN offloads all dataplane tasks to specialized NICs to achieve better latency and CPU efficiency than software-based KBN, it also takes away the operator’s control over network sharing policies. Providing policy support in multi-tenant hardware KBN brings unique challenges – namely, preserving ultra-low latency and low CPU cost, finding a well-defined point of mediation, and rethinking traffic shapers. We present Justitia to address these challenges with three key design aspects: (i) Split Connection with message-level shaping, (ii) sender-based resource mediation together with receiver-side updates, and (iii) passive latency monitoring. Using a latency target as its knob, Justitia enables multi-tenancy policies such as predictable latencies and fair/weighted resource sharing. Our evaluation shows Justitia can effectively isolate latency-sensitive applications at the cost of slightly decreased utilization and ensure that throughput and bandwidth of the rest are not unfairly penalized.

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@inproceedings {276976,
author = {Yiwen Zhang and Yue Tan and Brent Stephens and Mosharaf Chowdhury},
title = {Justitia: Software {Multi-Tenancy} in Hardware {Kernel-Bypass} Networks},
booktitle = {19th USENIX Symposium on Networked Systems Design and Implementation (NSDI 22)},
year = {2022},
isbn = {978-1-939133-27-4},
address = {Renton, WA},
pages = {1307--1326},
url = {https://www.usenix.org/conference/nsdi22/presentation/zhang-yiwen},
publisher = {USENIX Association},
month = apr,

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