DeepSeek-V4 on Day 0: From Fast Inference to Verified RL with SGLang and Miles

SGLang and Miles added day-0 inference and RL support for DeepSeek-V4, covering 1.6T Pro and 284B Flash. The post cites a 1M-token context, FP4 MoE expert weights, 128-token SWA, and 4:1 or 128:1 KV compression. The key systems detail is ShadowRadix coherence across three KV pools and two compression-state pools.

Why it matters: HKR-H/K/R all pass: a DeepSeek-V4 day-0 systems stack, concrete context/compression mechanisms, and clear deployment-cost stakes. The systems depth narrows reach, but no hard-exclusion rule is triggered.