arXiv AI By Geng Zhang, Fangzhao Zhang, Cong Xie, Tiantian Fan, Yang You

Split-KV: Efficient Context Parallelism for Training Diffusion Drafters

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Split-KV introduces a context‑parallelism technique for training diffusion drafters, keeping key/value shards local and limiting per‑layer attention communication to query‑sized tensors. This approach exploits the asymmetry between short draft queries and long contexts, enabling efficient load balancing via a cost‑aware longest‑processing‑time‑first strategy. Experiments show that at a CP size of 64, Split‑KV achieves 85–91 % weak‑scaling efficiency and up to 3.67× speedup over the best baseline, with less than 1 % load imbalance.

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