Usage
This checkpoint does not load in upstream vLLM. The MoESQ repository installs a patched
vLLM v0.30.0 (the paired48_nvfp4 MoE backend and sparse-storage loader) together with the
kernels. It needs an NVIDIA Blackwell SM100 (B200, GB200) or SM120 (RTX 5090, RTX PRO 6000) GPU and a
CUDA toolkit >= 12.8; SM103 (B300) and SM121 (DGX Spark) are not supported.
git clone --recurse-submodules https://github.com/IST-DASLab/MoESQ.git && cd MoESQbash integrations/vllm/install.sh && source .venv-vllm/bin/activate # 4x B200, tensor + expert parallelvllm serve ISTA-DASLab/Qwen3.5-397B-A17B-P48NVFP4-MoESQ \ --tensor-parallel-size 4 --enable-expert-parallel
vLLM selects the backend automatically.
Evaluation
OpenLLM Leaderboard v1: 6-task average
The six tasks are ARC-Challenge (25-shot), HellaSwag (10-shot), MMLU (5-shot),
TruthfulQA-MC2 (0-shot), Winogrande (5-shot) and GSM8K (5-shot, greedy). Scores use
lm-evaluation-harness with the full test sets, as mean ± std over 3 few-shot seeds
(1234, 0, 1). Recovery is computed per seed against dense, then averaged.
Table with columns: Model, Avg, Recovery vs dense| Model | Avg | Recovery vs dense |
|---|
| Qwen3.5-397B-A17B (dense) | 80.24 ± 0.14 | — |
| This model (MoESQ) | 75.07 ± 0.21 | 93.55 % |
| SparseGPT + GPTQ (same W4A4 paired-4:8 target) | 70.61 ± 0.25 | 88.00 % |
| OBR (same target) | 73.42 ± 0.36 | 91.50 % |
| JSQ (same target) | 62.96 ± 0.14 | 78.46 % |
Most of the gap to the baselines comes from GSM8K, which moves by about ±1.3 points across
few-shot seeds. Reasoning benchmarks have not been run for this model yet.
Compression details
Table with columns: Field, Value| Field | Value |
|---|
| Weights | NVFP4 (E2M1), one FP8-E4M3 scale per 32 dense K elements, FP32 per-tensor global scale |
| Activations | NVFP4, dynamic per-32 group scales, FP32 per-tensor global scale stored per expert linear |
| Sparsity | Paired 4:8 along K: in every 8 consecutive elements (4 pairs), exactly 2 pairs are kept |
| Compressed layers | Routed MoE experts (gate_proj, up_proj, down_proj) in all 60 layers |
| Left in BF16 | lm_head, embeddings, full and linear attention, norms, router (mlp.gate), shared experts, vision tower / merger, the MTP head |
The scale group is 32 because the Blackwell sparse NVFP4 MMA (SM100 and SM120) requires one scale per 32 dense
K elements, which is 16 surviving elements after the 4:8 prune.
Sparse storage layout (paired48_sparse, pair-bitmask v1)
Packed NVFP4 stores two adjacent K elements per byte, so one pair is one byte. A paired-4:8
weight therefore has exactly 2 nonzero bytes in every 4-byte chunk. Each routed-expert linear
stores:
Table with columns: Tensor, dtype / shape, Contents| Tensor | dtype / shape | Contents |
|---|
weight_sparse_packed | uint8 [out, K/4] | the 2 kept bytes of every 4, in K order |
weight_sparse_mask | uint8 [out, K/16] | 4 bits per 4-byte chunk (exactly 2 set; bit i means byte i is kept); the low nibble is the lower-K chunk |
weight_scale | float8_e4m3 [out, K/32] | block scales (linear layout) |
quantization_config carries "paired48_sparse": {"layout": "pair-bitmask", "version": 1}.
The encoding is lossless: converting to and from dense NVFP4 is exact, and every tensor in
this upload was checked with a round trip. At load time vLLM rebuilds each layer's dense
packed weight and compresses it into the kernel's own layout.
Recipe (MoESQ, arm "gw2")
The full MoESQ config for this run is in moe_sq_config.yaml.
- Init: GPTQ, 4-bit, 512 calibration samples, percdamp 0.1, block size 128. Masks come
from paired-4:8 pruning.
- Refinement: masks and weight values are learned jointly for 10 epochs on 8,192 mixed
calibration sequences of up to 4,096 tokens, with activations fake-quantized to NVFP4. The
objective is the block-output reconstruction error weighted by the router gate
(
gate_weight_exponent = 2). Learning rates are 2e-4 for masks and 2.5e-5 for weights.
Citation
@article{moesq, title = {Hardware-Native Joint Sparse-Quantization for Trillion-Scale Mixture-of-Experts}, author = {TODO}, journal = {arXiv preprint arXiv:TODO}, year = {TODO}}
For questions, open a discussion here or contact
kwanhee.lee@postech.ac.kr.