Efficient Direct-Connect Topologies for Collective Communications#
NSDI '25 digest Program Adjacent pick 28–30 April 2025
- Authors / tier: Liangyu Zhao, Tapan Chugh, Arvind Krishnamurthy (University of Washington); Siddharth Pal, Jason Fantl, Prithwish Basu, Joud Khoury (Raytheon BBN); Weiyang Wang (MIT CSAIL). Adjacent.
- Why: Sits at the physical-topology/collective-communication boundary that increasingly drives ML cluster fabric design — relevant context for DC topology and interconnect decisions.
- What: An algorithmic framework that jointly synthesizes direct-connect topologies and their communication schedules, then picks the topology/schedule best suited to a given workload's latency-vs-bandwidth profile and degree constraints.
- How: Start from small optimal base topologies and schedules, then iteratively expand them to large sizes; a novel polynomial-time algorithm produces efficient collective schedules for well-known large-scale graph topologies. Validated on multiple testbeds plus large-scale simulation.
- Where applicable: Degree-constrained direct-connect networks (e.g., optical/cabled interconnects without a central switch). General framework; most valuable where you control the physical topology.