Runbook section `2026-10-11 — unquantized KV at 2 x 200,000`: the dtype law
(only bf16|fp8, no K/V split; the QSA block key is dtype-fixed, which is why
bf16 costs 1.89x and not 2x), the pool formula that reproduces both live
boots within 0.1%, the seqs-3-to-2 provenance (the tcclaviger fork's
torch.compile constraint, not radiance's), the boot ledger, and the A/B.
The A/B, fp8 control arm through a transient FRANK_ARCHON_ENV_FILE drop-in:
prefill -29% (4,379 -> 3,126 cold), TTFT at the full window +25% (the 2 x 197k
pair: 110.5 s -> 138.1 s), decode inside the +-3% band on two of three passes,
draft acceptance UP 0.661 -> 0.740. The price is prefill, not decode. Open
call for Frank: keep exact KV, or take the cheap fp8 2 x 200k fit (pool 3,648).
Also corrects two stale index entries (w4dn8 said STAGED, fp8-native said
ACTIVE), adds the worklog entry, and commits the verification tool as
scripts/probe-frank-archon-kv.py — it carries the probe law that cost two
false negatives: radiance answers in reasoning_content, so a chat probe with a
small budget reads as empty content + finish_reason stop on a healthy server.
Tests 368/368.
The KV pool at the fp8 shape backed 386,904 tokens — 1.93 sessions of the
served 200,000 window, so a second full-height conversation preempted to the
host/disk prefix tiers. Moving the cache to bf16 (the engine's only
unquantized rung; `--kv-cache-dtype` takes bf16|fp8 and has no per-tensor
K/V split) doubles what a token costs: 7.3125 -> 14.625 KiB per rank
(kv_attn 26.00 -> 52.00 KiB per 4-token page + kv_qsa_bkey 3.25 -> 6.50).
Pool 3543 -> 6912 MiB (437k tokens, >= 2 x 200,000), and the weights slab
pays for all of it: 26071 -> 22208 MiB, the pair pinned to the measured
card ceiling 29,120 MiB (card 31,856 - 1,710 consumed outside both budgets
- 1,024 free). The resident set that leaves VRAM spills into the pinned host
pool, so 40960 -> 44928 MiB, and the prefix host tier doubles with the entry
size (58.50 -> 117 KiB): 4096 -> 8192 MiB. Pinned ledger ~147 GiB, ttm floor
140000 -> 150000 (cap 200 GiB).
--max-num-seqs 3 -> 2: two slots x the window is the capacity contract, and
the "seqs 2 cannot boot" law is the retired tcclaviger fork's torch.compile
query_start_loc constraint, not radiance's (radiance booted seqs 2 in the
fp8-native era; the 2026-10-06 sweep had 2 and 3 tied inside +-3%). Bonus:
the fused all-reduce is now declared over 2 x 3 = 6 rows, under the 25-row
bound at which the wht6 wire is bit-exact.
Cost, paid twice on this engine: idle KV VRAM is also the expert cache's
spillover (lends 2.69 GiB + 740 MiB of arena), so the pool steals weight
residency from the slab AND the lendable cache. Priors: 2.14 GiB of stolen
weights cost 2.5% decode (MAX_MODEL_LEN 262144), the EVC ladder's other
direction cost 8.9%. Prediction -3..-8% vs the fp8 control (136 t/s at 44.5k,
acceptance 0.7246); the deploy boot ledger and live probes are the referee.
Seams: MAX_SEQS/HOST_POOL/KV_DTYPE/PREFIX_HOST literals follow the shape, and
two new invariants guard it — the KV pool must back seqs x max-model-len at
the declared dtype (an engine hard limit: an over-long request is accepted
then refused as too large to ever fit; the formula reproduces the fp8 boot's
386,904 to within 0.1%), and the VRAM pair must stay inside the ceiling.
The 2026-10-09 wire aliases become the service names everywhere:
systemd units, serve scripts, env files and FRANK_* variables,
deploy-plan/deploy-remote service keys, container names, Prometheus
job names + alert rules, Grafana dashboard queries, bats seams,
runbook filenames, homepage/AGENTS lore, and historical prose.
Rollback tags renamed in lockstep. Residue in the tree: zero.
Retired frank-medium/small/npu names are history and stay.
Known casualty: scripts/patches/*.patch context lines were rewritten;
those retired-era vLLM-fork patches no longer apply byte-exact.
Frank