* studio: add speculative decoding support (ngram-mod, on by default)
Enable n-gram speculative decoding for GGUF models in Unsloth Studio.
Uses llama.cpp's ngram-mod mode which gives 10-40% faster generation
with zero VRAM cost via a 4MB fixed hash table that auto-resets on
low acceptance rates.
Backend:
- Add speculative_type field to LoadRequest, LoadResponse, and
InferenceStatusResponse pydantic models
- Add speculative_type parameter to LlamaCppBackend.load_model()
with allowlist validation (ngram-simple, ngram-mod)
- Pass --spec-type, --spec-ngram-size-n 16, --draft-max 24 flags
to llama-server when ngram-mod is active
- Default to ngram-mod for non-vision GGUF models server-side
- Silently skip speculative decoding for vision models (unsupported
in llama.cpp server-context.cpp)
Frontend:
- Add speculative_type to TS API types
- Add speculativeType/loadedSpeculativeType to chat runtime store
with default value of "ngram-mod"
- Add On/Off toggle in Model settings section (GGUF only, hidden
for vision models), included in dirty check for Apply/Reset
- Wire speculative_type through model load request and response
- Restore speculative type state on page refresh/reconnect
* [pre-commit.ci] auto fixes from pre-commit.com hooks
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* fix: remove server-side speculative decoding override
The backend was overriding speculative_type=None to "ngram-mod" for
non-vision GGUF models, which prevented users from disabling spec
decoding via the UI toggle. The frontend store already defaults to
"ngram-mod", so the backend fallback was redundant and blocked the
explicit "Off" setting.
* fix: use recommended ngram-mod params from llama.cpp docs
Update speculative decoding params to match the recommended values
from llama.cpp docs (docs/speculative.md):
--spec-ngram-size-n 24 (was 16, docs say small n not recommended)
--draft-min 48 (was 0)
--draft-max 64 (was 24, docs note MoEs need long drafts)
Also fix comment: ngram-mod uses ~16 MB (4M entries * 4 bytes),
not 4 MB.
* [pre-commit.ci] auto fixes from pre-commit.com hooks
for more information, see https://pre-commit.ci
* add benchmark table and references to speculative decoding comment
Include speedup numbers from llama.cpp PRs #18471 and #19164 as an
inline comment so future readers understand the expected gains.
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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
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