Pyrrha: Congestion-Root-Based Flow Control to Eliminate Head-of-Line Blocking in Datacenter#
NSDI '25 digest Program Adjacent pick 28–30 April 2025
- Authors / tier: Kexin Liu, Zhaochen Zhang, Chang Liu, Yizhi Wang (Nanjing University); Vamsi Addanki, Stefan Schmid (TU Berlin); additional co-authors at Nanjing University and Huawei. Adjacent.
- Why: Head-of-line blocking in lossless DC fabrics (PFC and friends) is a recurring operational pain. Congestion-root-based flow control is a notable angle for anyone working on RDMA/lossless fabrics.
- What: A flow-control scheme that targets the root of congestion rather than reacting hop-by-hop, aiming to eliminate HoL blocking. (Detailed mechanism not captured in this digest pass; confirm specifics from the paper.)
- Where applicable: Lossless datacenter fabrics; involvement of Huawei co-authors suggests hardware-oriented validation. Treat as fabric-class research relevant to RDMA deployments.