Compare commits

...

2 Commits

Author SHA1 Message Date
Georgi Gerganov
6eddb1c6e3 pi : add rule to use gh CLI for GitHub resources
Assisted-by: llama.cpp:local pi
2026-04-30 09:49:54 +03:00
Georgi Gerganov
c6dbd31146 docs : update speculative decoding parameters after refactor (#22397)
Update docs/speculative.md to reflect the new parameter naming scheme
introduced in PR #22397:

- Replace --draft-max/--draft-min with --spec-draft-n-max/--spec-draft-n-min
- Replace --spec-ngram-size-n/m with per-implementation variants
- Add documentation for all new --spec-ngram-*- parameters
- Update all example commands

Assisted-by: llama.cpp:local pi
2026-04-30 09:44:48 +03:00
2 changed files with 109 additions and 21 deletions

View File

@@ -4,6 +4,7 @@ General:
- By very precise and concise when writing code, comments, explanations, etc.
- PR and commit titles format: `<module> : <title>`. Lookup recents for examples
- Don't try to build or run the code unless you are explicitly asked to do so
- Use the `gh` CLI tool when querying PRs, issues, or other GitHub resources
Coding:
- When in doubt, always refer to the CONTRIBUTING.md file of the project

View File

@@ -33,18 +33,18 @@ An example to use this approach can be the rewriting of source code by a LLM.
This implementation looks for the last n-gram in history that matches the current n-gram and creates a draft using the m tokens following the matched n-gram. It is the simplest self-speculative approach with minimal overhead.
```
llama-server [...] --spec-type ngram-simple --draft-max 64
llama-server [...] --spec-type ngram-simple --spec-draft-n-max 64
```
#### n-gram Map Key (`ngram-map-k`)
This implementation looks for the current n-gram of size n (called the _key_) in the token history. If the key n-gram is followed by the same m tokens (called the _mgram_) multiple times, it creates a draft using these m tokens. This approach requires a minimum number of occurrences (argument `--spec-ngram-min-hits`, default is 1) before generating drafts.
This implementation looks for the current n-gram of size n (called the _key_) in the token history. If the key n-gram is followed by the same m tokens (called the _mgram_) multiple times, it creates a draft using these m tokens. This approach requires a minimum number of occurrences (argument `--spec-ngram-map-k-min-hits`, default is 1) before generating drafts.
The number of accepted tokens is stored for each used n-gram.
**Example:**
```
llama-server [...] --spec-type ngram-map-k --draft-max 64
llama-server [...] --spec-type ngram-map-k --spec-draft-n-max 64
```
#### n-gram Map Key-4-Values (`ngram-map-k4v`)
@@ -55,7 +55,7 @@ The number of accepted tokens is stored for each used n-gram.
**Example:** Server options to be used if there are a lot of longer repetitions.
```
llama-server [...] --spec-type ngram-map-k4v --spec-ngram-size-n 8 --spec-ngram-size-m 8 --spec-ngram-min-hits 2 --draft-max 64
llama-server [...] --spec-type ngram-map-k4v --spec-ngram-map-k4v-size-n 8 --spec-ngram-map-k4v-size-m 8 --spec-ngram-map-k4v-min-hits 2 --spec-draft-n-max 64
```
### n-gram Mod (`ngram-mod`)
@@ -80,9 +80,9 @@ Currently, a single hash pool is shared across all server slots, so different re
# notes:
# - small `n` are not recommended
# - MoEs require long drafts
# - dense models: can reduce `--draft-min` and `--draft-max`
# - dense models: can reduce `--spec-ngram-mod-n-min` and `--spec-ngram-mod-n-max`
llama-server ... --spec-type ngram-mod --spec-ngram-size-n 24 --draft-min 48 --draft-max 64
llama-server ... --spec-type ngram-mod --spec-ngram-mod-n-match 24 --spec-ngram-mod-n-min 48 --spec-ngram-mod-n-max 64
```
Applications:
@@ -105,21 +105,90 @@ Example Video:
If a draft model is combined with a draftless decoding the draftless decoding has higher precedence.
### General Speculative Parameters
```
--draft, --draft-n, --draft-max N number of tokens to draft for speculative decoding (default: 16)
(env: LLAMA_ARG_DRAFT_MAX)
--draft-min, --draft-n-min N minimum number of draft tokens to use for speculative decoding
(default: 0)
(env: LLAMA_ARG_DRAFT_MIN)
[...]
--spec-type [none|ngram-cache|ngram-simple|ngram-map-k|ngram-map-k4v|ngram-mod]
type of speculative decoding to use when no draft model is provided
(default: none)
--spec-ngram-size-n N ngram size N for ngram-simple/ngram-map speculative decoding, length
of lookup n-gram (default: 12)
--spec-ngram-size-m N ngram size M for ngram-simple/ngram-map speculative decoding, length
of draft m-gram (default: 48)
--spec-ngram-min-hits N minimum hits for ngram-map speculative decoding (default: 1)
(env: LLAMA_ARG_SPEC_TYPE)
--spec-default use default speculative decoding
```
### Draft Model Parameters
```
--spec-draft-model, -md, --model-draft FNAME
draft model for speculative decoding (default: unused)
(env: LLAMA_ARG_SPEC_DRAFT_MODEL)
--spec-draft-hf, -hfd, -hfrd, --hf-repo-draft <user>/<model>[:quant]
HuggingFace repository for the draft model
--spec-draft-n-max N
number of tokens to draft for speculative decoding (default: 16)
(env: LLAMA_ARG_SPEC_DRAFT_N_MAX)
--spec-draft-n-min N
minimum number of draft tokens to use for speculative decoding (default: 0)
(env: LLAMA_ARG_SPEC_DRAFT_N_MIN)
--spec-draft-p-split, --draft-p-split P
speculative decoding split probability (default: 0.10)
(env: LLAMA_ARG_SPEC_DRAFT_P_SPLIT)
--spec-draft-p-min, --draft-p-min P
minimum speculative decoding probability (greedy) (default: 0.75)
(env: LLAMA_ARG_SPEC_DRAFT_P_MIN)
--spec-draft-ctx-size, -cd, --ctx-size-draft N
size of the prompt context for the draft model (default: 0, 0 = loaded from model)
(env: LLAMA_ARG_SPEC_DRAFT_CTX_SIZE)
--spec-draft-ngl, -ngld, --gpu-layers-draft, --n-gpu-layers-draft N
max. number of draft model layers to store in VRAM, either an exact number, 'auto', or 'all' (default: auto)
(env: LLAMA_ARG_N_GPU_LAYERS_DRAFT)
--spec-draft-device, -devd, --device-draft <dev1,dev2,..>
comma-separated list of devices to use for offloading the draft model
--spec-draft-replace, --spec-replace TARGET DRAFT
translate the string in TARGET into DRAFT if the draft model and main model are not compatible
```
### n-gram Mod Parameters
```
--spec-ngram-mod-n-match N
ngram-mod lookup length (default: 24)
--spec-ngram-mod-n-min N
minimum number of ngram tokens to use for ngram-based speculative decoding (default: 48)
--spec-ngram-mod-n-max N
maximum number of ngram tokens to use for ngram-based speculative decoding (default: 64)
```
### n-gram Simple Parameters
```
--spec-ngram-simple-size-n N
ngram size N for ngram-simple speculative decoding, length of lookup n-gram (default: 12)
--spec-ngram-simple-size-m N
ngram size M for ngram-simple speculative decoding, length of draft m-gram (default: 48)
--spec-ngram-simple-min-hits N
minimum hits for ngram-simple speculative decoding (default: 1)
```
### n-gram Map Key Parameters
```
--spec-ngram-map-k-size-n N
ngram size N for ngram-map-k speculative decoding, length of lookup n-gram (default: 12)
--spec-ngram-map-k-size-m N
ngram size M for ngram-map-k speculative decoding, length of draft m-gram (default: 48)
--spec-ngram-map-k-min-hits N
minimum hits for ngram-map-k speculative decoding (default: 1)
```
### n-gram Map Key-4-Values Parameters
```
--spec-ngram-map-k4v-size-n N
ngram size N for ngram-map-k4v speculative decoding, length of lookup n-gram (default: 12)
--spec-ngram-map-k4v-size-m N
ngram size M for ngram-map-k4v speculative decoding, length of draft m-gram (default: 48)
--spec-ngram-map-k4v-min-hits N
minimum hits for ngram-map-k4v speculative decoding (default: 1)
```
### `--spec-type TYPE`
@@ -140,21 +209,40 @@ Specifies a type of speculative decoding without draft model.
./llama-server [...] --spec-type ngram-simple
```
### `--spec-ngram-size-n N`
### `--spec-ngram-*-size-n N`
Sets the size N of the lookup n-gram for n-gram map based speculative decoding.
The n-gram size N determines how many tokens in a row to look back when searching for matching patterns.
### `--spec-ngram-size-m M`
Each n-gram implementation has its own parameter:
- `--spec-ngram-simple-size-n` for `ngram-simple`
- `--spec-ngram-map-k-size-n` for `ngram-map-k`
- `--spec-ngram-map-k4v-size-n` for `ngram-map-k4v`
- `--spec-ngram-mod-n-match` for `ngram-mod`
### `--spec-ngram-*-size-m M`
Sets the size M of the draft m-gram for n-gram map based speculative decoding.
The m-gram size determines how many tokens to draft when a match is found.
Larger values can provide more speedup but may reduce acceptance rate.
### `--spec-ngram-min-hits H`
Each n-gram implementation has its own parameter:
- `--spec-ngram-simple-size-m` for `ngram-simple`
- `--spec-ngram-map-k-size-m` for `ngram-map-k`
- `--spec-ngram-map-k4v-size-m` for `ngram-map-k4v`
### `--spec-ngram-*-min-hits H`
This option defines how often a key has to appear in the token history to be used as a draft (default is 1).
Each n-gram implementation has its own parameter:
- `--spec-ngram-simple-min-hits` for `ngram-simple`
- `--spec-ngram-map-k-min-hits` for `ngram-map-k`
- `--spec-ngram-map-k4v-min-hits` for `ngram-map-k4v`
## Statistics
Each speculative decoding implementation prints statistics.
@@ -180,4 +268,3 @@ statistics ngram_map_k: #calls(b,g,a) = 6 1690 26, #gen drafts = 26, #acc drafts
- `#gen tokens`: number of tokens generated by this implementation (including rejected tokens)
- `#acc tokens`: number of tokens accepted by the main model
- `dur(b,g,a): durations of begin (new prompt), generation and accumulation (process acceptance).