Measured quality (this exact artifact, served)
Gold contract: WikiText, 8 × 512 tokens (4,088 scored positions), teacher =
BF16 source, teacher distribution truncated to top-8192 logits per
position; student served by vanilla vLLM with the pinned GridBook plugin
(the same stack documented below), score_positions=all.
Table with columns: metric, value| metric | value |
|---|
| KL(teacher‖student), mean | 1.2221 |
| KL, confident positions (n=2,935) | 1.0293 |
| KL, p99 | 8.805 |
| KL, max | 18.078 |
| WikiText PPL (direct, same serve) | 20.95 |
Internal ablation at the identical 87.4 GB byte budget: against the
weight-only-cost allocation it replaced, the activation-aware (aqua-both)
allocation shipped here measures −3.4% mean KL / −7.2% confident-KL /
−11.0% p99-KL — all outside the ±0.7% cross-session repeat envelope —
while direct PPL is statistically unchanged (+1.0%, inside the ~1.5%
spread observed when re-serving identical bytes across sessions).
Precision map
Body assignment: 2.346 bits per parameter over the body's assignment
tensor payload (including deduplicated codebook sidecars). Per-serving-unit
format counts:
Table with columns: format, units| format | units |
|---|
| FP8_BLOCK_UE8M0_SOURCE (lossless FP8 passthrough) | 125 |
| FP8_CB K48 / K44 / K36 / K28 (codebook FP8) | 90 / 5 / 34 / 69 |
| NVFP4_CB K12 / K14 / K16 / K18 (codebook NVFP4) | 42 / 18 / 2 / 2 |
Activation contracts as served by the pinned runtime: NVFP4_CB units execute
W4A4 (E2M1 group-16 activations, static UE4M3 global scale) on the 32
routed-MoE stages; FP8_CB and FP8-source units decode to BF16 and run a BF16
GEMM (weight-only). 189 declared passthrough tensors; no orphan scale planes.
Layer map

One column per layer (0–42), one row per projection; every cell is one
serving unit, colored by the format the allocator chose, rendered from this
artifact's own quant_config.json. Bright mint = verbatim FP8-source
passthrough (lossless); teal = FP8 codebook rungs, brighter with codebook
size K; navy/violet = NVFP4 codebook rungs; hatched = pinned at source
precision and never offered to the allocator (router gates, the attention
compressor, the indexer's compressor and score head — plus embedding and
lm_head off-grid). Routed-expert rows are the packed per-layer expert
stack: all 256 routed experts in a layer share one format, a serving
invariant, not a simplification.
How to read it: the projections feeding attention state (wq_a, wkv,
wo_a) ship as lossless FP8 source everywhere; shared experts stay rich
(K48 or source); and the routed-expert mass — the bulk of the bytes — runs
NVFP4-CB K12 through the first ~21 layers while the allocator concentrates
its 8-bit budget on late-layer experts (FP8-CB K28 on layers 22–38, where
the sensitivity card priced flips as most expensive). On the 11 FP8-CB
expert layers gate/up ship as separate stacks and fuse at load; NVFP4-CB
layers ship fused gate_up. K sizes the codebook — the weight coding only;
the activation contract is set by the format family (table above).
The same map is browsable cell-by-cell, alongside every other PrismaQuant
artifact, in the allocation explorer.
What this artifact does and does not claim
- Claimed: the KL/PPL numbers above, the byte size, and that vanilla vLLM
with the pinned GridBook plugin loads and serves it (eager and CUDA-graph
mode) on Blackwell.
- Not claimed: matched-budget serving performance parity. This is a
body-only artifact (see below), and the matched-budget performance-parity
gate structurally requires construction units and telemetry this artifact
class cannot produce; it is recorded as scoped-out on the shipcard, not
passed. Decode on NVFP4_CB units routes to the native codebook LUT path.
Under the gated runtime (
gridbook==0.8.8) large-batch prefill on codebook
units rode a grouped dequant-to-BF16 bridge; GridBook 0.8.9 defaults the
fused persistent-B decode-in-mainloop kernels on, so this artifact's 32
FP4-CB routed expert layers take that lane with no flags set (its 11
FP8-CB routed layers ship per-role codebooks and keep the bridge, announced
per layer; dense CB prefill keeps the bridge). Same activation contract
either way — a default-environment 0.8.9 serve of this exact artifact
re-measured kl_mean +0.17 % / PPL −0.06 % against the recorded gold, inside
the ±0.7 % cross-session KL envelope.
- The KL teacher is top-8192-truncated (mass renormalized); tail mass beyond
rank 8192 is not scored.
- The MTP / speculative-decode sidecar is not included. The source's
mtp. namespace (4,705 tensors) is excluded from this body-only artifact
and recorded in quant_config.json provenance.
Serving
Tested stack: vanilla vLLM (Blackwell / SM121, CUDA 13) with the GridBook
out-of-tree quantization plugin, gridbook==0.8.10.
pip install gridbook==0.8.10
vllm serve rdtand/DeepSeek-V4-Flash-0731-PrismaQuant-AQUA-gridbook-87GB-spark-vllm \
--quantization gridbook --trust-remote-code \
--tokenizer-mode deepseek_v4 \
--generation-config vllm \
--kv-cache-dtype fp8 \
--kv-cache-memory-bytes 10737418240 \
--max-model-len 131072 \
--max-num-seqs 2 \
--max-num-batched-tokens 2048 \
--gpu-memory-utilization 0.90 \
--enable-auto-tool-choice --tool-call-parser deepseek_v4 \
--reasoning-parser deepseek_v4 \
--default-chat-template-kwargs '{"reasoning_effort":"low"}' \
--compilation-config '{"mode":0,"cudagraph_mode":"FULL_DECODE_ONLY","cudagraph_capture_sizes":[1,2]}' \
--host 0.0.0.0 --port 8000
Every flag above is load-bearing on a 128 GB single-Spark box. The short form
that omits them does not serve this model well, and in two cases does not serve
it at all.
--max-model-len 131072 — the config default is 1,048,576. Left at the
default, vLLM sizes the KV pool against the machine's entire RAM (GPU and host
share one pool on a Spark), reaches ~106 GiB of hard allocation on a 121.6 GiB
box, and the container is OOM-killed after weights have already loaded
successfully. It looks like a load failure; it is a sizing failure.
--kv-cache-memory-bytes 10737418240 — a fixed 10 GiB pool (~637k tokens).
Passing it also skips memory profiling entirely, which is what removes the
autotune/warmup spike that triggers the kill above.
--compilation-config … FULL_DECODE_ONLY — decode is launch-overhead-bound on
this hardware. Capture is what makes decode throughput reproducible; without
it decode runs materially slower.
--default-chat-template-kwargs '{"reasoning_effort":"low"}' — vLLM defaults
DeepSeek-V4 to reasoning_effort="high" whenever a request omits it, which
injects a maximum-deliberation system prompt. The model obeys: a default-path
"what is 2+2" can run for over twenty minutes without terminating. This is
stock upstream vLLM behaviour, not a quantization artifact. "none" disables
thinking entirely.
--enable-auto-tool-choice --tool-call-parser deepseek_v4 --reasoning-parser deepseek_v4
— required for tool calls and reasoning segments to parse.
Known issue on newer vLLM — read before serving without the flags above.
On vLLM 0.27+, whose default cudagraph_mode is FULL_AND_PIECEWISE, CUDA-graph
capture fails in GridBook's MoE router (_padded_route performs a host sync inside
the capture region) and the engine exits during startup rather than serving. Tracked
as gridbook#47. The explicit
--compilation-config above avoids it; --enforce-eager also works but costs
substantial decode throughput, since decode on this hardware is launch-overhead-bound.
If you are benchmarking this artifact, check which of those two you are on before
quoting a tokens/sec number.
No forked runtime, no custom vLLM build: GridBook registers the quant method
through vLLM's plugin interface. Weights are a single model.safetensors plus
cb_codebooks.pqcb (codebook sidecar) and quant_config.json.
Provenance
- Built by PrismaQuant — probe →
AURA/AQUA cost → knapsack allocation → codebook export — at commit
a24fce2b, allocation recipe aqua-both.
- Artifact
model_sha 3d3b8bde1343fe33… (full value and the complete gate
record in shipcard.json inside the repo).
- Quantized from the FP8-native source; FP8 source tensors selected by the
allocator ship as verbatim lossless copies.
Author: Robert Tand — robert.tand@icloud.com