After 383b5cc shipped 175K + 0.97 (text) and 140K + 0.95 (vision),
audit showed the cliffs the backoff was protecting against fire on
every config we ship — they're independent of max-model-len. So the
context capacity was wasted protection.
Push text-only ceilings up:
long-text: 175K + 0.97 → 185K + 0.975
bounded-thinking: 175K + 0.97 → 185K + 0.975
Vision stays at 140K + 0.95: tried 185K + 0.98, 185K + 0.975, 160K
+ 0.97; all reopened Cliff 2 (DeltaNet GDN forward buffer) at the
130K-char stress class. Vision tower's ~1 GiB persistent + the new
patches' persistent allocations (P38 K_full/V_full ~750 MiB at 185K
+ compile-safe sidecar ~138 MiB) leave too little headroom for the
GDN intermediate buffer at 30K+ token prefills on this variant.
P37 disabled on vision (was on for parity with long-text but P37's
MoE intermediate cache pool is no-op on dense Qwen3.6-27B and the
env gate doesn't free memory anyway).
Verification at the new ceilings:
long-text 185K + 0.975: verify-full 8/8 (MTP AL 2.66),
130K-char tool-prefill stress PASS
long-vision 140K + 0.95: verify-full 8/8 (MTP AL 3.27),
130K-char tool-prefill stress PASS
bounded-thinking 185K + 0.975: not re-booted in this final state
(config identical to long-text +
one --structured-outputs flag,
no memory delta expected)
Docs updated: SINGLE_CARD.md picker table + activation-budget +
per-variant blurbs; engines/VLLM.md TL;DR + KV cache table; engines/
LLAMA_CPP.md "when to use vLLM"; STRUCTURED_COT.md "When to pick
this over long-text"; models/qwen3.6-27b/README.md per-variant lines;
docs/CLIFFS.md "Update 2026-05-01 PM" with full bisection sweep and
final decision.
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
