Poseidon: Efficient, Robust, and Practical Datacenter CC via Deployable INT
Poseidon: Efficient, Robust, and Practical Datacenter CC via Deployable INT
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发表时间:
2023
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通讯作者:
Weitao Wang;M. Moshref;Yuliang Li;G. Kumar;T. Ng;Neal Cardwell;Nandita Dukkipati
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作者:
Weitao Wang;M. Moshref;Yuliang Li;G. Kumar;T. Ng;Neal Cardwell;Nandita Dukkipati
The difficulty in gaining visibility into the fine-timescale hop-level congestion state of networks has been a key chal-lenge faced by congestion control (CC) protocols for decades. However, the emergence of commodity switches supporting in-network telemetry (INT) enables more advanced CC. In this paper, we present Poseidon , a novel CC protocol that ex-ploits INT to address blind spots of CC algorithms and realize several fundamentally advantageous properties. First, Poseidon is efficient : it achieves low queuing delay, high throughput, and fast convergence. Furthermore, Poseidon decouples bandwidth fairness from the traditional AIMD control law, using a novel adaptive update scheme that converges quickly and smooths out oscillations. Second, Poseidon is robust : it realizes CC for the actual bottleneck hop , and achieves max-min fairness across traffic patterns, including multi-hop and reverse-path congestion. Third, Poseidon is practical : it is amenable to incremental brownfield deployment in networks that mix INT and non-INT switches. We show, via testbed and simulation experiments, that Poseidon provides significant improvements over the state-of-the-art Swift CC algorithm across key metrics – RTT, throughput, fairness, and convergence – resulting in end-to-end application performance gains. Evaluated across several scenarios, Poseidon lowers fabric RTT by up to 50%, reduces time to converge up to 12 × , and decreases throughput variation across flows by up to 70%. Collectively, these improvements reduce message transfer time by more than 61% on average and 14.5 × at 99.9p.