Georgi Gerganov b9f3599fb1 llama : do not map foreign ranges into a backend buffer (#30405)
* llama : do not map foreign ranges into a backend buffer

A buffer created from a host pointer pins everything that it wraps. When
several contexts share the same file (lazy tensors, MoE tensors kept on the
CPU with -cmoe), the single buffer that spans the first and the last tensor
of a context also wraps the ranges owned by the other contexts, pinning data
that the backend never reads.

For models with per-layer token embeddings this pins the whole lazy tensor
into the GPU buffer (27 GiB for Qwen3.8-Flash-Next IQ4_NL), defeating the
point of reading it lazily.

Instead, compute the file ranges of each context and subtract the ranges
owned by the other contexts, then create one buffer per range. Weights that
are mapped in more than one context (e.g. token_embd.weight) keep being part
of the range of every context that uses them.

Assisted-by: pi:llama.cpp/Qwen3.8-Flash-Next

* llama : enable prefetch on macOS

The prefetch hint of the tensors marked as prefetchable is a no-op on macOS,
so their pages are faulted in one by one while the graph runs. madvise
(MADV_WILLNEED) behaves as expected here, so add the platform to the guard.

With the lazy per-layer token embeddings of Qwen3.8-Flash-Next IQ4_NL read
from a cold file cache, prompt processing goes from 356 / 375 / 475 t/s to
735 / 749 / 788 t/s for pp512 / pp2048 / pp4096.

Assisted-by: pi:llama.cpp/Qwen3.8-Flash-Next

* llama : use a plain buffer list per context

Assisted-by: pi:llama.cpp/Qwen3.8-Flash-Next
2026-10-13 17:28:15 +03:00
2026-06-12 15:53:26 +02:00
2026-10-04 21:38:19 +05:30
2026-02-02 08:38:55 +02:00
2026-09-09 15:56:27 +02:00

llama.cpp

llama

Quick start

A few options to get llama.cpp installed on your machine:

# curl
curl -LsSf https://llama.app/install.sh | sh

# powershell
irm https://llama.app/install.ps1 | iex

Once installed:

# Download and run a model directly from Hugging Face
llama cli -hf ggml-org/Qwen3.5-0.8B-GGUF

# Launch OpenAI-compatible API server
llama serve -hf ggml-org/Qwen3.5-0.8B-GGUF
VLM session with `llama cli` VLM session with llama cli Built-in web UI against `llama serve` running Qwen 3.6 Built-in web UI against llama serve

Description

The main goal of llama.cpp is to enable LLM (and VLM) 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 build on top of the ggml library.

Supported backends

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

Documentation

Tools

Development

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!
  • Read the CONTRIBUTING.md for more information

Acknowledgements

  • yhirose/cpp-httplib - Single-header HTTP server, used by llama-server - MIT license
  • nothings/stb - Single-header image format decoder, used by multimodal subsystem - Public domain
  • nlohmann/json - Single-header JSON library, used by various tools/examples - MIT License
  • mackron/miniaudio - Single-header audio format decoder, used by multimodal subsystem - Public domain
  • sheredom/subprocess.h - Single-header process launching solution for C and C++ - Public domain
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Description
llama.cpp fork with AVX1, NUMA, SM75 Turing, and FastMTP optimizations
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