P4 - Language Consortium

P4 Developer Days - Detecting Stragglers in Programmable Data Plane
2025-08-20 09:00 UTC
Date: August 20, 2025Time 9:00am Pacific
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Abstract
Flow scheduling mechanisms in modern datacenters aim to reduce flow completion time (FCT). However, scheduling mechanisms that operate without prior knowledge, such as PIAS, or with imprecise flow information like QClimb, can inadvertently introduce stragglers–packets within a flow that experience significantly higher queueing delays than others. These stragglers can lead to prolonged FCT, undermining the goals of flow scheduling. In this talk, we present StragFlow, a data-plane tool for straggler detection. We implemented StragFlow in P4 using 740 lines of code. We evaluated StragFlow using real-world network traces and demonstrate that it can effectively detect stragglers across different scheduling schemes and various link conditions. Our results show that StragFlow can provide valuable insights into straggler distribution, helping operators diagnose and mitigate flow scheduling issues to improve overall network performance.
Speaker
Riz Maulana is a PhD Candidate within IRIS Cluster in the Department of Mathematics and Computer Science at Eindhoven University of Technology, The Netherlands. His research interest includes programmable data plane, probabilistic data structures, and network monitoring.
