arXiv Machine Learning By Yichao Fu, Yuxuan Zhang, Minshen Zhang, Ruitian Wang, Junda Chen, Hao Zhang

FastAFD: When Does Attention-FFN Disaggregation Pay on Rack-Scale NVLink?

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FastAFD is an attention‑FFN disaggregation engine designed for rack‑scale NVLink systems such as GB200 NVL72. It overlaps the mixture‑of‑experts computation of one microbatch with the attention of another, achieving up to 1.17× higher throughput than the best wide‑expert‑parallelism vLLM configuration on Qwen3 and Qwen3.5, and matching it on MiniMax‑M2.5. An analytical model predicts AFD performance within 3% using only colocated vLLM profiles, revealing that speedup comes from batch and overlap gains that outweigh disaggregation costs, and that speculative decoding further boosts performance for light‑expert models.

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arXiv Machine Learning
Oct 16

When the KV Cache Is Slower Than the GPU: Scaling Remote KV Tiers for Context-Parallel Prefill

The paper investigates the performance impact of using a remote KV cache tier for long‑context language model serving. In a disaggregated deployment of GLM‑5.3 on 8xB300 nodes, enabling the remote tier initially increased the 16k‑token p99 latency from 3.96 s to 17.3 s, and synchronous loading caused severe queue instability. By sharding the KV store across context‑parallel ranks, partitioning the remote tier, adding asynchronous loading, and fixing client bugs, the authors reduced the p99 latency from 83.32 s to 0.67 s and increased prefill throughput by 14–34 %. whyItMatters":"The study demonstrates that careful sharding and asynchronous handling of remote KV caches can dramatically improve latency and throughput in large‑scale LLM serving systems."

By Muhammad Ibrahim
arXiv AI
Oct 27

Prefetch-Steered Routing: Deterministic Cache-Aware Expert Selection for Offloaded Mixture-of-Experts Decoding

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By Siming Huang
arXiv Machine Learning
Jul 20

DualKV: Shared-Prompt Flash Attention for Efficient RL Training with Large Rollouts and Long Contexts

arXiv:2605. 15422v3 Announce Type: replace Abstract: Modern RL post-training methods such as GRPO and DAPO train on N response sequences of R tokens sampled from a shared prompt of P tokens, but standard FlashAttention replicates all P prompt tokens N times across both forward and backward passes -- duplicating compute and memory on identical hidden states.

By Jiading Gai, Shuai Zhang, Xiang Song, Bernie Wang, George Karypis