DeepSeek-V4-Flash NVFP4 TP2 W4A4 v1

This is a single-download, two-node GB10 serving bundle. It combines an offline-prepared NVIDIA NVFP4 W4A4 target with the native three-stage DSpark speculative draft.

This is not a drop-in Transformers checkpoint. The target has a custom rank-contiguous TP=2 physical layout and requires the matching loader in Anemll/dspark-vllm-gx10, branch dspark-nvfp4-a4w4.

Bundle layout

The root target contains 87 Safetensors files, 3,483 tensors, and 168,266,881,608 payload bytes. The draft contains 4,705 tensors and 10,862,838,300 payload bytes. bundle-manifest.json records the complete layout and provenance.

The target and draft remain two explicit model paths at runtime: mount the repository root as the target and dspark/ as the speculative model.

Requirements

• two NVIDIA DGX Spark or equivalent GB10/SM121 nodes;
• TP=2 with a dedicated node-to-node fabric;
• enough local storage for the complete bundle on each node;
• the custom vLLM runtime branch linked above;
• an ARM64 runtime image built from that branch.

The checkpoint is not supported as a one-node TP=1 model. The prepared target format itself is pinned to TP=2.

Download

Run on both nodes, choosing a local SSD path with sufficient free space:

hf download anemll/DeepSeek-V4-Flash-NVFP4-TP2-W4A4-v1 \
  --local-dir /srv/dspark/models/DeepSeek-V4-Flash-NVFP4-TP2-W4A4-v1

Runtime setup

Clone the matching runtime branch on both nodes:

git clone --branch dspark-nvfp4-a4w4 \
  https://github.com/Anemll/dspark-vllm-gx10.git
cd dspark-vllm-gx10

Use an image built from this branch. The legacy 0.1.1 image does not contain the prepared bulk direct reader unless it has been rebuilt from the branch:

FINAL_IMAGE=dspark-vllm-gx10:nvfp4-a4w4-v1 ./scripts/build-image.sh

Set the following values in both config/head.env and config/worker.env, in addition to their normal rank, fabric, NCCL, cache, and rendezvous fields:

DSPARK_VLLM_IMAGE=dspark-vllm-gx10:nvfp4-a4w4-v1
DSPARK_MODEL_HOST=/srv/dspark/models/DeepSeek-V4-Flash-NVFP4-TP2-W4A4-v1
DSPARK_DRAFT_MODEL_HOST=/srv/dspark/models/DeepSeek-V4-Flash-NVFP4-TP2-W4A4-v1/dspark
SERVED_MODEL_NAME=deepseek-v4-flash-nvfp4-dspark

DSPARK_WEIGHT_LOAD_FORMAT=auto
DSPARK_MOE_BACKEND=auto
DSPARK_SPECULATION_MODE=dspark
MTP_NUM_TOKENS=5
VLLM_DSPARK_CONFIDENCE_SCHEDULER=off
VLLM_DSPARK_CONFIDENCE_THRESHOLD=0.0

VLLM_DSV4_NVFP4_CUTLASS_PREPARED_LOAD=1
VLLM_DSV4_NVFP4_CUTLASS_PREPARED_MANIFEST_SHA256=REPLACE_WITH_MANIFEST_SHA256
VLLM_DSV4_NVFP4_CUTLASS_PREPARED_DIRECT_READ=1

Use the first field of dspark-nvfp4-tp2-repack.json.sha256 as the manifest value. Keep the global MoE backend at auto: the prepared target is scoped to FlashInfer CUTLASS by its loader, while the native DSpark draft requires its own backend selection. Direct reads are the prepared-loader default; 0 selects the slower diagnostic mmap path.

Start rank 1 first, then rank 0:

# WORKER / rank 1
./scripts/start-node.sh config/worker.env

# HEAD / rank 0, after rank 1 enters the rendezvous
./scripts/start-node.sh config/head.env

When passwordless worker SSH is configured in the head environment, the head can launch both ranks:

./scripts/start-cluster.sh config/head.env config/worker.env

Startup verification

Follow the container log on either rank:

cid="$(sudo docker ps -q --filter label=com.docker.compose.service=vllm-dspark)"
sudo docker logs -f "$cid"

A valid prepared bulk load reports:

• NVFP4_PREPARED event=enabled ... io_mode=preadv;
• 43 event=layer_load records;
• event=complete layers=43 reads=344 copies=344 ... io_mode=preadv;
• 43 post-load records with transforms=0 and backend FLASHINFER_CUTLASS.

After startup:

curl -fsS http://HEAD_HOST:8888/health
curl -fsS http://HEAD_HOST:8888/v1/models

Validated load performance

The bulk direct reader was validated end to end on two GB10 nodes:

The run reached HTTP health 200, exposed the expected model, kept both ranks out of OOM state, and returned a coherent smoke response. Raw evidence is in nvfp4-prepared-direct-read-full-3689b1c.json.

Prefill comparison

These are warmed, server-side prefill rates on the same two-node TP=2 cluster. Prefill is target-only and does not benefit from speculative decoding.

The reports are same-size aggregates, not paired identical-prompt trials. See the comparison and raw-artifact links.

Decode and agentic comparisons

All rows use MTP=5, confidence scheduling off, probabilistic draft sampling, no draft/verify overlap optimization, temperature zero, and 512 requested tokens per stream.

The canonical control is a three-trial median; its W4A4 row is one post-promotion run. The agentic row is a clean W4A4 production measurement; the older timing-instrumented concurrency study is deliberately not used as a control. The agentic prompt SHA-256 is 6173a7ae0ea3c64b364d0c405be28808efb8486c68a7011e966d31ce222c1736, and all eight W4A4 streams passed the automated no-collapse diagnostic.

The report is intentionally mixed rather than marketing a single decode number: W4A4 lost about 9% in the exploratory canonical comparison, while the high-acceptance agentic path reached 360.68 aggregate tok/s without a clean legacy control. See the full serving comparison and raw JSON links.

Limitations

• This artifact is tied to the custom prepared-loader contract and TP=2.
• It is not supported by stock Transformers or stock vLLM.
• The target and speculative draft have separate physical layouts and must be mounted at the two paths shown above.
• Decode performance depends strongly on prompt content and draft acceptance; report prompt, concurrency, acceptance, output length, and timing convention with every result.
• The agentic no-collapse diagnostic is not a comprehensive quality evaluation.
• The target originates from NVIDIA's NVFP4 checkpoint and the draft from the native DeepSeek V4 Flash DSpark lineage; review the upstream licenses and terms as well as the files included here.

Reproducibility

• Runtime source: Anemll/dspark-vllm-gx10
• Prepared format manifest: dspark-nvfp4-tp2-repack.json
• Bundle manifest: bundle-manifest.json
• Benchmark summary: w4a4-dspark-serving-comparison.md