* Make the drafter probabilistic and the target verify by rejection sampling
* Drop stale spec_draft_q before drafting
* Fallback to argmax sampling for grammar-constrained requests and adding flag for enabling probabilistic draft sampling. Default flag value is greedy.
* Support grammar-constrained requests in rejection sampling
* Fix - renormalize distribution after masking
* copy rng on sampler copy and re-accept drafted tokens on replay
* Fix draft sampler sharing the target's rng stream
* Simplify the rejection sampler's inputs and move replay to the server
* Truncate the draft candidates along with the draft
---------
Co-authored-by: praneshgo <227579474+praneshgo@users.noreply.github.com>
Co-authored-by: Pranesh Gonegandla <pgonegandla@nvidia.com>
* adapt common
* add common_batch
* wip
* wip: spec
* cont
* common_speculative_process
* server_batch to use common_batch
* rm some stale calls
Assisted-by: Claude Fable 5.1
* migrate mtmd
* handle imrope, handle return val of add()/add_embd()
* add spec zeros vector
* add warning on zero fill path
* server: fix speculation after an image
Pass the actual position to the drafter after an image, instead of the
token count. Affects every drafter, not just DFlash.
* rename draft n_past to pos0
n_past is used to denote number of tokens and this parameter is meant to be a position
* speculative: fix failed to decode mtmd chunk with DFlash
When using DFlash w/ vision models, the drafter memory fails to
allocate new tokens because images report a fixed offset. Stop copying
them to allow the drafter to continue.
* address PR feedback
limit M-RoPE skip to images only, allow audio to pass through. Clean up
comments to align to the updated implementation
* dflash : fuse the encoder into the KV injection decode
The encoder is a single fc + norm, but running it as a separate
llama_encode forced a device-to-host round trip of its output before the
injection decode could re-upload it, plus a second graph build per
round. Fold the encoder into the decoder's embd branch and feed the
target features directly to one llama_decode.
Assisted-by: Claude Fable
* nit
* Apply batched suggestions from code review
Co-authored-by: Ruixiang Wang <wangruixiang07@outlook.com>
* Fix missing references from renaming
---------
Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@huggingface.co>
Co-authored-by: Ruixiang Wang <wangruixiang07@outlook.com>
* spec : add DFlash2 support (local convolution + candidate selector) (#27342)
* support DFlash2
* Add p_min in DFlash2
Assisted-by: Claude Opus 5
* Revert unnecessary changes
Assisted-by: Claude Opus 5
* Revert draft sampling in rejection sampling
Assisted-by: Claude Opus 5
* Refactor code structure
Assisted-by: Claude Opus 5
* Delete embedding scaling
Assisted-by: Claude Opus 5
* Gate output transforms on DFlash2
Assisted-by: Claude Opus 5
* Optimize Dflash 2 cost
Assisted-by: Claude Opus 5
* Avoid using atoi
Assisted-by: Claude Opus 5
* Modify comments
Assisted-by: Claude Opus 5
* Move llama_model_dflash_selector_top_k to llama-ext.h
Assisted-by: Claude Opus 5
* Formatting
Assisted-by: Claude Opus 5
* Apply patch to fix the mrope bug
Assisted-by: Claude Opus 5
* fix ci
Assisted-by: Claude Opus 5
* Fix graph number calculation
Assisted-by: Claude Opus 5
* rename hid and unary
Assisted-by: Claude Opus 5
---------
Co-authored-by: Jian Chen <jianchen0311@gmail.com>
Co-authored-by: Xuan-Son Nguyen <son@huggingface.co>
* revert top-k.cu changes
---------
Co-authored-by: Zihan Zhang <tiancaizhangdaxian@sjtu.edu.cn>
Co-authored-by: Jian Chen <jianchen0311@gmail.com>
* Add benchmark-only synthetic speculative acceptance to llama-server and llama-cli
* Address review comments
* Address review comments
* Add some comments in the code
* fit: also take into account n_streams
* server: make the draft context follow the target context
With a non-unified KV cache the target context now holds n_ctx_train
tokens per sequence, while the draft context was still created with
n_ctx = 0 and fell back to n_ctx_train / n_streams per sequence. A slot
filled beyond that point makes the draft batch fail to decode, and the
server answers 500 on the request.
The draft context now takes its size from the target context, so both
hold the same number of tokens per sequence. Contexts that share their
cells with the target no longer need the kv_size override.
The memory reserved for the draft model before fitting is measured at
the largest context the target can take, since the draft context grows
with the target and a fixed byte margin cannot express that.
* fit: take an optional second model into account
Illustrates the alternative discussed on the draft context fix. The
memory of a draft or MTP context is currently handed to the fit as a
fixed byte margin, which cannot express a memory that grows with the
context the fit is still deciding on.
common_fit_params now takes an optional second model that shares the
devices of the main one. Its context follows the main context and its
memory is measured again whenever that context changes, so the reduce
path stays exact instead of conservative. A model that cannot be
measured on its own, such as a shared cell MTP context, is skipped with
a warning and the main model is fitted alone.
This drops the reservation block in the server, which no longer has to
probe the trained context size of the target to guess an upper bound.
---------
Co-authored-by: Pascal <admin@serveurperso.com>
* dspark: support speculators-format checkpoints (SpecForge exports)
Speculators-format DSpark drafts (e.g. SpecForge exports for the
Gemma-4-26B-A4B target) differ from the dense DeepSpec checkpoints in
three ways:
- the config nests the backbone hparams under transformer_layer_config
and gives the extract layers as aux_hidden_state_layer_ids
- the block is the DFlash 1+N fill-in layout: the anchor slot is a bonus
token, not a prediction slot. Written as dflash.bonus_anchor; such
drafts build the block and read the mask positions exactly like
DFlash (n_max drafts from a 1+n_max block), only the Markov/confidence
sampling comes from DSpark
- the draft output vocab may be reduced (draft_vocab_size < vocab_size)
with a d2t remap table. The converter expands lm_head/markov_w2 back
to the full vocab and synthesizes an lm_head bias of -1e9 on the rows
the draft cannot produce, so the runtime needs no d2t remapping. Such
drafts ship their own (now optional) token_embd/output tensors instead
of sharing the target's
Verified against gemma4-26b-a4b-dspark: greedy outputs are byte-identical
with and without the draft; acceptance 0.46, mean draft len 3.7 (n_max 6).
Co-authored-by: desovo7 <942845546@qq.com>
Assisted-by: Claude Fable 5
* dspark: fold the speculators draft class into DSparkModel
One class now covers every DSpark variant. What used to pick the class is
a single flag, because the arch name turns out to be the only thing that
separates the two families: SpecForge also exports a flat schema that
carries no speculators_* fields yet still uses the 1+N bonus-anchor block,
so keying on those fields would silently mis-read its drafts.
Also rename i0 to i_first_pred in the draft read loop and the Markov head,
and give the head a real bonus_anchor bool instead of testing i0 > 0.
Converting the Qwen3-8B DeepSpec draft and both gemma-4 speculators drafts
produces byte-identical GGUFs. The one behaviour change is that the
markov_head_type check now also covers the DeepSpec checkpoints, which
previously skipped it.
Co-authored-by: desovo7 <942845546@qq.com>
Assisted-by: Claude Opus 5
* dspark: address review comments
- rename bonus_anchor to sample_from_anchor (GGUF key and code), matching
the checkpoint config field; absent key still means anchor-first
- rework the reduced draft vocab to match EAGLE3: d2t is written as I64
absolute target ids and the logits are scattered at runtime, instead of
expanding lm_head/markov_w2 and synthesizing an output bias at conversion
- move the t2d skip to modify_tensors, like EAGLE3
- drop _is_specforge: the arch name only picks the sample_from_anchor
default, embed/lm_head sharing is decided by the draft vocab size
- deduplicate the tok_embd create_tensor left behind by the rebase
Verified with the RedHat gemma-4-31b speculator draft: greedy output is
byte-identical with and without the draft; acceptance 0.26 (n_max 7).
Co-authored-by: desovo7 <942845546@qq.com>
Assisted-by: Claude Fable 5
* dspark: fold the sample_from_anchor read into the block_size block
* dspark: fix flake8 continuation indent
* clean up
* dspark: key the sample_from_anchor default off the export format
Co-authored-by: desovo7 <942845546@qq.com>
Assisted-by: Claude Fable
* dspark: drop t2d in filter_tensors
Co-authored-by: desovo7 <942845546@qq.com>
Assisted-by: Claude Fable
* dspark: map model.lm_head instead of bypassing the dflash prefix
Co-authored-by: desovo7 <942845546@qq.com>
Assisted-by: Claude Fable
---------
Co-authored-by: desovo7 <942845546@qq.com>
Co-authored-by: ruixiang63 <wangruixiang07@outlook.com>
* common : auto-detect spec type from draft GGUF metadata
When -md loads a local draft model without --spec-type, the sidecar
inference in common_models_handler_apply only checks HF repo sidecars
and misses local files. The draft model loads into VRAM but speculative
decoding never activates (types stays NONE).
Read general.architecture from the draft GGUF header and map:
dflash + markov_w1.weight tensor -> draft-dspark
dflash without markov head -> draft-dflash
Assisted-by: opencode
* common : address review feedback on spec-type auto-detect PR
- Fix comment spacing to match surrounding style (/* .x = */ not /*.x =*/)
- Add LOG_INF when auto-detection fires so users can see why spec decoding enabled
- Document single-file assumption for split-GGUF edge case
Addresses bot review feedback on #26814.
* common : move spec-type GGUF auto-detect into speculative module
- add common_speculative_types_from_gguf() in speculative.cpp/.h
- use gguf_context_ptr (RAII) from ggml-cpp.h
- reduce comments to a single line per AGENTS.md style
Addresses review feedback on #26814
* common : add doc note and join SPC_INF line in spec-type auto-detect
Assisted-by: opencode
* Enable backend sampling with token speculation
* Clamp the mask sum before converting it into the sampled index
* Add a numeric context parameter declaring the maximum outputs one sequence
* More fixes
* Don't reuse memory for output views.
* Match dist between CPU and GPU
* Fix CPU and backend sampling mismatches
* Simpify some of the changes
* Fix tests on Vulkan
* More test fixes
* Rebase changes
* Rebase and address review comments
* Address review comments
* Address review comments
* Update src/llama-sampler.cpp
Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>
---------
Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>
* Get started with Onyx
* Add architecture
* Skip keys handled in super()
* Loading tensors
* Shorten
* Graph
* Apply suggestion from @pcuenca
* Remove norm now embedding in transformers weights
* Add eot
* Explicit output_multiplier
* Handle post_norm_eps
* No super call; unhardcode eot.
The pattern `self._set_vocab_gpt2()` seems preferred throughout the
codebase, and it allows `set_vocab()` to be called from a different part
of the Python class hierarchy: the drafter model converter that we may
need eventually.
* Register for drafting
* DFlash: inherit rope type from the linked target.
Another option would be to store it in the gguf file itself.
* mmproj conversion
Note: some fields to be renamed after the implementation works. We are
keeping compatibility with the reference Meta gguf for testing purposes.
* "clip" header declarations
* Load mmproj
* Pre-processing
* Graph
* Go back to using delimiters.
Otherwise our generations are worse.
Transformers does not use them. We need to trace inputs to verify
whether they are equivalent.
* downsample_factor -> merge_size
* Add vision graph
lol, forgot from a previous commit
* Additional renames, align with llama.cpp / transformers
* Prefer _size instead of independent _h and _w
* Fix token layout
Co-authored-by: Young Han <younghan@fb.com>
* onyx: bring the chat parser onto the onyx branch
common/chat.cpp on this branch has no Onyx handling, so a converted model
serves malformed chat: the assistant preamble leaks into content
("to=self<|message|>...") and tool calls fail with
HTTP 500 "The model produced output that does not match the expected
peg-native format"
common_chat_params_init_onyx exists on onyx-fair-patch, added there by
8bb73dd3d. It was never on this branch, so this is not a regression --
the two lines developed independently.
The code here is taken verbatim from that commit. It is the clean side of
`git merge origin/onyx-fair-patch`: chat.cpp is one of the files that
merges without conflict. The full merge is not viable -- it produces 13
conflicts, including add/add on conversion/onyx.py and src/models/onyx.cpp
where the q_norm-folding and metadata-scale approaches contradict each
other, and #4/#7 are stacked on this branch's side of that.
Verified on this branch: builds with 0 errors, converts an Onyx checkpoint,
and serving it gives "4" for "What is 2+2?" plus a correct
get_weather {"city":"Paris"} tool call, where the unported branch gives the
two failures above.
No converter or runtime changes are included, so this should not interact
with the q_norm work.
Co-authored-by: Beto de Paola <betodepaola@meta.com>
* Less params, bilinear pos-emb interpolation as a graph op instead of CPU
* Map to symbolic V_MMPROJ instead of strings
* Make a couple params explicit
* Patchify via build_inp()
* No param for rope_theta
* Small cleanup
* Restore blank line
* Unpermute, to adapt to the latest transformers checkpoint
* Apply norm after token embeddings
This follows the latest transformers approach.
* Remove duplicated function
* build_vit
* onyx: use the model rope theta on sliding-window layers
* DFlash: conversion from transformers drafter
* Revert rope_type derivation from target
NOTE: this breaks compatibility with Meta's distributed DFlash GGUFs, as
the Q/K are stored in "NEOX" (rotated half) format, like in
transformers.
* Apply suggestion from @pcuenca
* Set model type
* Remove comment that will become obsolete
* Hardcode post_norm_rms_eps instead of new param
* Derive SWA+RoPE pattern from gguf array or scalar
* Fix model type <-> number of layers
* Reorder
* Rename
* Fix typo
* DFlash: seed the draft KV cache from multimodal embedding batches
`common_speculative_impl_draft_dflash::process()` returned early on any batch carrying embeddings, so an image prefill never had its target-layer features fused through the DFlash encoder and injected into the draft's KV cache. That left a hole spanning the image's positions, and the next injection at a post-image position failed to initialize its batch:
```
decoding image batch 1/1, n_tokens_batch = 256
decode: failed to initialize batch
llama_decode: failed to decode, ret = -1
process: llama_decode(ctx_dft) failed rc=-1 (n_tokens=17, offset=0)
srv decode: failed to process speculative batch
```
Every image request with `--spec-type draft-dflash` failed with HTTP 500. Text-only was unaffected, since those batches carry token ids and were let through.
Restore the earlier condition, which admits a batch that is either tokens or embeddings and skips only the degenerate neither/both cases. The rest of `process()` is already layout-agnostic -- it gathers features via `llama_get_embeddings_layer_inp()` and indexes `batch_in.pos[]` / `batch_in.seq_id[]`, none of which assume token ids -- so this is the whole fix.
Validated against `muse-glimmer-30B-bf16.gguf` + `mmproj-muse-glimmer-30B-bf16.gguf` + a DFlash draft head, on an image describe-the-shapes request:
- before: HTTP 500, `failed to process speculative batch`
- after: HTTP 200, draft acceptance 0.34012 (167 accepted / 491 generated), mean len 3.04
Output equivalence holds, which is the property that matters: at temperature 0 the drafted response is byte-identical to the same request served with no draft attached (1213/1213 chars), so the draft is drafting correctly through the image context rather than merely not crashing.
* Conversion: prefer rewrite to mapping
* Revert "Conversion: prefer rewrite to mapping"
This reverts commit a92d0ac584d315e876741e85b6dad3dbc8b23bf7.
* fix lint
* sliding_window metadata is not optional
* disable state save/load
* Apply suggestion from @pcuenca
---------
Co-authored-by: Young Han <younghan@fb.com>
Co-authored-by: Beto de Paola <betodepaola@meta.com>
Co-authored-by: Daniel Han <michaelhan2050@gmail.com>
Co-authored-by: ruanrms <ruanslv@gmail.com>
Co-authored-by: Xuan Son Nguyen <son@huggingface.co>
Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@huggingface.co>
This commit contains a suggestion to reduce some code duplication in
common_speculative_init when adding the enabled speculative decoding
configurations.
No tests were added but the existing server tests still passes with this
change:
```console
$ ./tests.sh unit/test_speculative.py -v -x
```
