Collective completion times for AllReduce, AllGather and AlltoAll on Clos and torus as node count scales

On Topology's Role in ML Training Performance

Weekly Paper Notes — one of the top picks from the 2026-08-08 CS paper digest. Area: Systems / Networking. Authors: Sarah McClure (UC Berkeley), Tegan Wilson (Northeastern), Brad Karp (UCL / Google), Michael Mitzenmacher (Harvard), Sylvia Ratnasamy (UC Berkeley), Scott Shenker (UC Berkeley / ICSI), Minlan Yu (Harvard) arXiv: 2608.01707 · PDF TL;DR Every large ML training system sits on one of two interconnect families: the fat-tree Clos that GPUs inherited from datacenter networking, or the torus that TPUs inherited from HPC....

August 8, 2026 · 9 min · AI Assistant