VCCL

An Efficient, Reliable and Observable Collective Communication Library in Large-scale GPU Training Clusters

Announce Type: replace Abstract: Large-scale LLM training requires collective communication libraries to exchange data among distributed GPUs. As a company dedicated to building and operating large-scale GPU training clusters, we encounter several practical limitations of NCCL in production, including 1) SM competition between computation and communication, 2) expensive restart costs under link failures, and 3) insufficient observability of transient collective communication anomalies. To...