mfritsche 396159c9d5 ggml-rknpu2: graceful abort with W8A8 hint on NPU IOVA exhaustion
rknn_create_mem returns null when the RK3588 NPU's ~4 GiB IOVA aperture is
full -- this backend maps every weight tensor into a single 4 GiB IOMMU window
(rkopnu currently ignores iommu_domain_id, so the IOMMUDomainManager's 2 GiB
domain-spreading is a no-op and everything lands in one 4 GiB window). The old
GGML_ASSERT reported a cryptic "Failed to allocate tensor memory via RKNN API"
with no guidance.

Replace it with a GGML_ABORT that names the aperture and points at the fix:
use a quantized GGUF, or set RKNPU_HYBRID=W8A8_STANDARD for on-the-fly INT8
weights (which fits >4 GiB dense f16 models -- e.g. Qwen2.5-3B-f16 runs at
~130 t/s pp512 that way). Also null-check the grow re-alloc path, which was a
latent copy of the same crash.

No behaviour change for models that fit; only the failure message improves.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EWpfhDgYNA21tETDP9ueBE
2026-07-20 04:21:49 +02:00
2026-06-07 20:50:54 +08:00
2026-06-07 20:50:54 +08:00
2026-06-07 20:50:54 +08:00
2026-06-07 20:50:54 +08:00
2026-06-07 20:50:54 +08:00
2026-02-02 08:51:25 +02:00
2026-06-02 17:44:35 +02:00
2026-02-02 08:38:55 +02:00

llama.cpp

llama

License: MIT Release Server Docker Winget

Manifesto / ggml / ops

LLM inference in C/C++


Rockchip-specific environment variables, parameters, and recipe

This is a Rockchip RK3588 NPU fork of llama.cpp. The performance-enhancement branch is the consolidated, benchmarked state: it adds two RK3588 NPU backends plus tuning knobs and benchmark docs. Base llama.cpp usage below is unchanged.

Two NPU backends (enable exactly one)

backend build flag kernel driver userspace notes
rknpu2 -DLLAMA_RKNPU2=ON vendor BSP or mainline via rkopnu closed librknnrt.so drives the NPU through Rockchip's runtime; fastest (vendor parity)
rocket -DGGML_ROCKET=ON mainline drivers/accel/rocket none (fully open) open ggml backend on the mainline accel driver; ~1.33× over CPU

Recipe — rknpu2 backend on a mainline kernel

The fully-open kernel path running the closed runtime at vendor speed:

  1. Kernel: build + load rkopnu (presents the vendor rknpu ioctl ABI on a mainline kernel; blacklist the in-tree rocket).
  2. Runtime: sudo install -m0644 librknnrt.so /usr/lib && sudo ldconfig (librknnrt ships in this tree at ggml/src/ggml-rknpu2/libs/).
  3. Build: cmake -B build -G Ninja -DLLAMA_RKNPU2=ON -DGGML_ROCKET=OFF && ninja -C build llama-server
  4. Run — raise the fd ceiling (librknnrt exports ~1500+ dmabuf fds per prefill) and pin to the A76 big cluster:
    ulimit -n 65536
    LD_LIBRARY_PATH=build/bin taskset -c 4-7 ./build/bin/llama-server \
        -m model.gguf -c 131072 -t 4 -fit off --host 0.0.0.0 --port 8090
    
    librknnrt round-robins single-core matmuls across all three NPU cores automatically.

Environment variables

rknpu2 backend (ggml/src/ggml-rknpu2/):

variable default effect
RKNPU_DEVICE RK3588 target SoC profile
RKNPU_CORES all comma-separated NPU core indices to use, e.g. 0,1,2
RKNPU_DOMAINS all restrict which op domains offload to the NPU
RKNPU_HYBRID built-in custom per-layer CPU/NPU split pattern

rocket backend (ggml/src/ggml-rocket/):

variable default effect
GGML_ROCKET_MIN_BATCH ROCKET_MIN_BATCH minimum M (batch) to offload; smaller matmuls (e.g. decode, M<32) stay on CPU
GGML_ROCKET_PROF off on backend teardown, dump per-matmul timing: setup / submit / npu_wait / free / tiles / calls
GGML_ROCKET_DEBUG off verbose per-matmul offload-decision logging
ROCKET_NOREPACK_TENSORS unset measurement only: comma-separated tensor-name substrings to force off the CPU_REPACK buftype so they reach the NPU. Routing more tensors to the NPU is generally slower (the CPU NEON repack kernel beats the NPU for those shapes) — for A/B experiments, not production

Useful parameters

  • -fit off — don't auto-shrink unset args to device memory when you set -c explicitly.
  • taskset -c 4-7 / -t 4 — pin to the four A76 cores; the CPU-side quantize/repack is the prefill bottleneck, so keep it off the little A55 cluster.

Benchmarks

Full data in docs/rknpu2-campaign-results.md. Summary (gemma-4-E2B-it-Q8_0, prefill, RK3588 NPU @ 1 GHz):

stack prefill tok/s
CPU (NEON, A76×4) ~34.9
rocket backend (mainline, open) ~4649
rknpu2 (vendor runtime, via rkopnu on mainline) ~51.5 (Rock 5 ITX) / ~49.5 (CoolPi GenBook, DDR-bound)

A persistent llama-server at 128K context on the rkopnu+rknpu2 path is soak-tested at 150/150 completions with all three NPU cores balanced and no crashes. Board-to-board differences are DDR-bandwidth-bound, not clock.


Recent API changes

Hot topics


Quick start

Getting started with llama.cpp is straightforward. Here are several ways to install it on your machine:

Once installed, you'll need a model to work with. Head to the Obtaining and quantizing models section to learn more.

Example command:

# Use a local model file
llama-cli -m my_model.gguf

# Or download and run a model directly from Hugging Face
llama-cli -hf ggml-org/gemma-3-1b-it-GGUF

# Launch OpenAI-compatible API server
llama-server -hf ggml-org/gemma-3-1b-it-GGUF

Description

The main goal of llama.cpp is to enable LLM inference with minimal setup and state-of-the-art performance on a wide range of hardware - locally and in the cloud.

  • Plain C/C++ implementation without any dependencies
  • Apple silicon is a first-class citizen - optimized via ARM NEON, Accelerate and Metal frameworks
  • AVX, AVX2, AVX512 and AMX support for x86 architectures
  • RVV, ZVFH, ZFH, ZICBOP and ZIHINTPAUSE support for RISC-V architectures
  • 1.5-bit, 2-bit, 3-bit, 4-bit, 5-bit, 6-bit, and 8-bit integer quantization for faster inference and reduced memory use
  • Custom CUDA kernels for running LLMs on NVIDIA GPUs (support for AMD GPUs via HIP and Moore Threads GPUs via MUSA)
  • Vulkan and SYCL backend support
  • CPU+GPU hybrid inference to partially accelerate models larger than the total VRAM capacity

The llama.cpp project is the main playground for developing new features for the ggml library.

Models

Typically finetunes of the base models below are supported as well.

Instructions for adding support for new models: HOWTO-add-model.md

Text-only

Multimodal

Bindings
UIs

(to have a project listed here, it should clearly state that it depends on llama.cpp)

Tools
  • akx/ggify download PyTorch models from Hugging Face Hub and convert them to GGML
  • akx/ollama-dl download models from the Ollama library to be used directly with llama.cpp
  • crashr/gppm launch llama.cpp instances utilizing NVIDIA Tesla P40 or P100 GPUs with reduced idle power consumption
  • gpustack/gguf-parser - review/check the GGUF file and estimate the memory usage
  • Styled Lines (proprietary licensed, async wrapper of inference part for game development in Unity3d with pre-built Mobile and Web platform wrappers and a model example)
  • unslothai/unsloth 🦥 exports/saves fine-tuned and trained models to GGUF (Apache-2.0)
Infrastructure
  • Paddler - Open-source LLMOps platform for hosting and scaling AI in your own infrastructure
  • GPUStack - Manage GPU clusters for running LLMs
  • llama_cpp_canister - llama.cpp as a smart contract on the Internet Computer, using WebAssembly
  • llama-swap - transparent proxy that adds automatic model switching with llama-server
  • Kalavai - Crowdsource end to end LLM deployment at any scale
  • llmaz - ☸️ Easy, advanced inference platform for large language models on Kubernetes.
  • LLMKube - Kubernetes operator for llama.cpp with multi-GPU and Apple Silicon Metal support"
Games
  • Lucy's Labyrinth - A simple maze game where agents controlled by an AI model will try to trick you.

Supported backends

Backend Target devices
Metal Apple Silicon
BLAS All
BLIS All
SYCL Intel GPU
OpenVINO [In Progress] Intel CPUs, GPUs, and NPUs
MUSA Moore Threads GPU
CUDA Nvidia GPU
HIP AMD GPU
ZenDNN AMD CPU
Vulkan GPU
CANN Ascend NPU
OpenCL Adreno GPU
IBM zDNN IBM Z & LinuxONE
WebGPU All
RPC All
Hexagon [In Progress] Snapdragon
VirtGPU VirtGPU APIR

Obtaining and quantizing models

The Hugging Face platform hosts a number of LLMs compatible with llama.cpp:

You can either manually download the GGUF file or directly use any llama.cpp-compatible models from Hugging Face or other model hosting sites, by using this CLI argument: -hf <user>/<model>[:quant]. For example:

llama-cli -hf ggml-org/gemma-3-1b-it-GGUF

By default, the CLI would download from Hugging Face, you can switch to other options with the environment variable MODEL_ENDPOINT. The MODEL_ENDPOINT must point to a Hugging Face compatible API endpoint.

After downloading a model, use the CLI tools to run it locally - see below.

llama.cpp requires the model to be stored in the GGUF file format. Models in other data formats can be converted to GGUF using the convert_*.py Python scripts in this repo.

The Hugging Face platform provides a variety of online tools for converting, quantizing and hosting models with llama.cpp:

To learn more about model quantization, read this documentation

llama-cli

A CLI tool for accessing and experimenting with most of llama.cpp's functionality.

  • Run in conversation mode

    Models with a built-in chat template will automatically activate conversation mode. If this doesn't occur, you can manually enable it by adding -cnv and specifying a suitable chat template with --chat-template NAME

    llama-cli -m model.gguf
    
    # > hi, who are you?
    # Hi there! I'm your helpful assistant! I'm an AI-powered chatbot designed to assist and provide information to users like you. I'm here to help answer your questions, provide guidance, and offer support on a wide range of topics. I'm a friendly and knowledgeable AI, and I'm always happy to help with anything you need. What's on your mind, and how can I assist you today?
    #
    # > what is 1+1?
    # Easy peasy! The answer to 1+1 is... 2!
    
  • Run in conversation mode with custom chat template
    # use the "chatml" template (use -h to see the list of supported templates)
    llama-cli -m model.gguf -cnv --chat-template chatml
    
    # use a custom template
    llama-cli -m model.gguf -cnv --in-prefix 'User: ' --reverse-prompt 'User:'
    
  • Constrain the output with a custom grammar
    llama-cli -m model.gguf -n 256 --grammar-file grammars/json.gbnf -p 'Request: schedule a call at 8pm; Command:'
    
    # {"appointmentTime": "8pm", "appointmentDetails": "schedule a a call"}
    

    The grammars/ folder contains a handful of sample grammars. To write your own, check out the GBNF Guide.

    For authoring more complex JSON grammars, check out https://grammar.intrinsiclabs.ai/

llama-server

A lightweight, OpenAI API compatible, HTTP server for serving LLMs.

  • Start a local HTTP server with default configuration on port 8080
    llama-server -m model.gguf --port 8080
    
    # Basic web UI can be accessed via browser: http://localhost:8080
    # Chat completion endpoint: http://localhost:8080/v1/chat/completions
    
  • Support multiple-users and parallel decoding
    # up to 4 concurrent requests, each with 4096 max context
    llama-server -m model.gguf -c 16384 -np 4
    
  • Enable speculative decoding
    # the draft.gguf model should be a small variant of the target model.gguf
    llama-server -m model.gguf -md draft.gguf
    
  • Serve an embedding model
    # use the /embedding endpoint
    llama-server -m model.gguf --embedding --pooling cls -ub 8192
    
  • Serve a reranking model
    # use the /reranking endpoint
    llama-server -m model.gguf --reranking
    
  • Constrain all outputs with a grammar
    # custom grammar
    llama-server -m model.gguf --grammar-file grammar.gbnf
    
    # JSON
    llama-server -m model.gguf --grammar-file grammars/json.gbnf
    

llama-perplexity

A tool for measuring the perplexity 1 (and other quality metrics) of a model over a given text.

  • Measure the perplexity over a text file
    llama-perplexity -m model.gguf -f file.txt
    
    # [1]15.2701,[2]5.4007,[3]5.3073,[4]6.2965,[5]5.8940,[6]5.6096,[7]5.7942,[8]4.9297, ...
    # Final estimate: PPL = 5.4007 +/- 0.67339
    
  • Measure KL divergence
    # TODO
    

llama-bench

Benchmark the performance of the inference for various parameters.

  • Run default benchmark
    llama-bench -m model.gguf
    
    # Output:
    # | model               |       size |     params | backend    | threads |          test |                  t/s |
    # | ------------------- | ---------: | ---------: | ---------- | ------: | ------------: | -------------------: |
    # | qwen2 1.5B Q4_0     | 885.97 MiB |     1.54 B | Metal,BLAS |      16 |         pp512 |      5765.41 ± 20.55 |
    # | qwen2 1.5B Q4_0     | 885.97 MiB |     1.54 B | Metal,BLAS |      16 |         tg128 |        197.71 ± 0.81 |
    #
    # build: 3e0ba0e60 (4229)
    

llama-simple

A minimal example for implementing apps with llama.cpp. Useful for developers.

  • Basic text completion
    llama-simple -m model.gguf
    
    # Hello my name is Kaitlyn and I am a 16 year old girl. I am a junior in high school and I am currently taking a class called "The Art of
    

Contributing

  • Contributors can open PRs
  • Collaborators will be invited based on contributions
  • Maintainers can push to branches in the llama.cpp repo and merge PRs into the master branch
  • Any help with managing issues, PRs and projects is very appreciated!
  • See good first issues for tasks suitable for first contributions
  • Read the CONTRIBUTING.md for more information
  • Make sure to read this: Inference at the edge
  • A bit of backstory for those who are interested: Changelog podcast

Other documentation

Development documentation

Seminal papers and background on the models

If your issue is with model generation quality, then please at least scan the following links and papers to understand the limitations of LLaMA models. This is especially important when choosing an appropriate model size and appreciating both the significant and subtle differences between LLaMA models and ChatGPT:

XCFramework

The XCFramework is a precompiled version of the library for iOS, visionOS, tvOS, and macOS. It can be used in Swift projects without the need to compile the library from source. For example:

// swift-tools-version: 5.10
// The swift-tools-version declares the minimum version of Swift required to build this package.

import PackageDescription

let package = Package(
    name: "MyLlamaPackage",
    targets: [
        .executableTarget(
            name: "MyLlamaPackage",
            dependencies: [
                "LlamaFramework"
            ]),
        .binaryTarget(
            name: "LlamaFramework",
            url: "https://github.com/ggml-org/llama.cpp/releases/download/b5046/llama-b5046-xcframework.zip",
            checksum: "c19be78b5f00d8d29a25da41042cb7afa094cbf6280a225abe614b03b20029ab"
        )
    ]
)

The above example is using an intermediate build b5046 of the library. This can be modified to use a different version by changing the URL and checksum.

Completions

Command-line completion is available for some environments.

Bash Completion

$ build/bin/llama-cli --completion-bash > ~/.llama-completion.bash
$ source ~/.llama-completion.bash

Optionally this can be added to your .bashrc or .bash_profile to load it automatically. For example:

$ echo "source ~/.llama-completion.bash" >> ~/.bashrc

Dependencies

  • yhirose/cpp-httplib - Single-header HTTP server, used by llama-server - MIT license
  • stb-image - Single-header image format decoder, used by multimodal subsystem - Public domain
  • nlohmann/json - Single-header JSON library, used by various tools/examples - MIT License
  • miniaudio.h - Single-header audio format decoder, used by multimodal subsystem - Public domain
  • subprocess.h - Single-header process launching solution for C and C++ - Public domain
S
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llama.cpp with RK3588 NPU (rknpu2 vendor backend) — perf-rknpu2 optimization branch
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