---
license: cc-by-nc-sa-4.0
tags:
- evaluation
- benchmark
- mixed-traffic
- speculative-decoding
- large-language-models
pretty_name: SpecMix (Mixed-Traffic Speculative Decoding Evaluation Set)
size_categories:
- 1K<n<10K
---

# SpecMix

A fixed, shuffled **mixed-traffic evaluation set** for speculative decoding (draft-then-verify)
serving. SpecMix interleaves requests from 10 public benchmarks the way a real serving endpoint
sees traffic, so throughput at high concurrency can be measured on a realistic mixture instead of
one homogeneous domain at a time. It is the mixed-traffic benchmark used in the DCore evaluation pipeline.

- **Paper**: [When Does Better Acceptance Pay? A Controlled Study of Speculative Decoding (arXiv:2610.24993)](https://arxiv.org/abs/2610.24993)
- **Code**: [github.com/ernie-research/DCore](https://github.com/ernie-research/DCore)

## Composition

| # | Source        | Rows | Source license        | Source (Hugging Face)                            |
|---|---------------|-----:|-----------------------|--------------------------------------------------|
| 1 | gsm8k         |  500 | MIT                   | [openai/gsm8k](https://huggingface.co/datasets/openai/gsm8k)                         |
| 2 | math500       |  500 | MIT (via prm800k)     | [HuggingFaceH4/MATH-500](https://huggingface.co/datasets/HuggingFaceH4/MATH-500)     |
| 3 | aime25        |   30 | CC-BY-NC-SA-4.0       | [MathArena/aime_2025](https://huggingface.co/datasets/MathArena/aime_2025)           |
| 4 | humaneval     |  164 | MIT                   | [openai/openai_humaneval](https://huggingface.co/datasets/openai/openai_humaneval)   |
| 5 | mbpp          |  257 | CC-BY-4.0             | [google-research-datasets/mbpp](https://huggingface.co/datasets/google-research-datasets/mbpp) |
| 6 | livecodebench |  500 | gated (terms apply)   | [livecodebench/livecodebench](https://huggingface.co/datasets/livecodebench/livecodebench) |
| 7 | mt-bench      |   80 | NC (see below)        | [lmsys/mt-bench](https://huggingface.co/datasets/lmsys/mt-bench)                     |
| 8 | alpaca        |  500 | CC-BY-NC-4.0          | [tatsu-lab/alpaca](https://huggingface.co/datasets/tatsu-lab/alpaca)                 |
| 9 | arena-hard    |  500 | Apache-2.0 (card); real user queries | [lmarena-ai/arena-hard-auto-v0.1](https://huggingface.co/datasets/lmarena-ai/arena-hard-auto-v0.1) |
| 10| swe-bench     |  300 | MIT                   | [princeton-nlp/SWE-bench_Lite](https://huggingface.co/datasets/princeton-nlp/SWE-bench_Lite) |
|   | **Total**     |**3331**|                       |                                                    |

Rows are the first N of each source (per the quota above), merged and shuffled with a fixed
seed (`42`), so the mix is frozen and reproducible.

## Fields

- `turns` — single-element list with the already-formatted prompt (identical string to what the
  per-dataset evaluation path produces).
- `source` — originating dataset name.
- `source_index` — row index inside that dataset (for cross-referencing).
- `gold` — gold answer for scorable sources (`gsm8k`, `math500`, `aime25`; 1,030 rows), `""` otherwise.
  Gold answers are numeric only; no code or patch content is included in this dataset.

## Usage

```python
from datasets import load_dataset
ds = load_dataset("wingchiuloong/specmix", split="train")
print(ds[0])
```

## Regeneration

This dataset is generated by `scripts/build_specmix_dataset.py` in the
[ernie-research/DCore](https://github.com/ernie-research/DCore) repository:

```bash
python scripts/build_specmix_dataset.py   # writes cache/dataset/specmix (seed=42)
```

## License and terms

- This combined dataset is distributed under **CC-BY-NC-SA-4.0** (the most restrictive license
  among its sources, determined by `aime25` CC-BY-NC-SA-4.0 and `alpaca`/`mt-bench` CC-BY-NC-4.0).
  **Research / non-commercial use only.**
- Each component remains under its original license; refer to the source links above for full
  terms. `mbpp` (CC-BY-4.0) requires attribution, which is provided here.
- `aime25` problem statements are © the Mathematical Association of America (MAA), as released by
  [MathArena](https://matharena.ai/).
- `livecodebench`, `lmsys/mt-bench` and `lmsys/lmsys-chat-1m` are gated on Hugging Face and
  subject to their own terms of use. `arena-hard` rows are real user queries from Chatbot Arena;
  they may contain personal data. Please respect the terms of the underlying sources when using
  the corresponding rows.
- If you are a rights holder of any source and would like this dataset removed or adjusted,
  please open an issue on the [ernie-research/DCore](https://github.com/ernie-research/DCore)
  repository.