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Xiaomi Unveils HySparse 2 Architecture as Core of MiMo‑V3

Xiaomi says the design cuts prefill compute roughly fivefold to make million-token contexts practical for interactive agent tasks.

Overview

  • Xiaomi announced HySparse 2 and said MiMo‑V3 will adopt it, positioning the release as a shift from model drops to architecture work focused on long contexts and agentic inference.
  • The company reports that at one million tokens HySparse 2 reduces prefill FLOPs to about one fifth of the prior approach and shrinks KV cache size to roughly one quarter.
  • Key techniques include KV Bridging, which builds cross-decoder key/value from self-decoder states, KV Reuse that shares cache inside mixed blocks, token-level selection to pick important tokens, and a recent-token forced window to let local and global tokens share the same KV cache.
  • Xiaomi says HySparse 2 raises retrieval and reasoning scores (MRCRv2 and RULER‑v2) while lowering metrics for agent and long‑context perplexity (AgentPPL and LongPPL), and the paper is available on arXiv for verification.
  • Xiaomi released the open‑source MiMo‑V2.6 Pro and Flash models immediately before this announcement and framed those models as practical steps toward exploring recursive self‑improvement by scaling reinforcement‑learning compute, a change that could lower compute costs for long‑context, interactive AI applications.