csantiago78andClaude Fable 5 7391a178e6 MoE expert cache: GPU-resident LRU cache for host-offloaded expert weights
Measured on Qwen3.8-Flash-Next UD-Q4_K_XL (512 experts, 10 routed, 28 expert
layers pinned to host RAM by -ot): expert routing has strong temporal locality
(LRU-64 ~67% hit rate over a mixed workload) even though the long-run expert
distribution is near-uniform, so a per-layer LRU cache of expert slices in VRAM
removes most of the per-token host-RAM streaming that bounds decode.

Mechanism (no custom CUDA kernels):
- companion tensors [ne0, ne1, K+1] per cached layer in the device buffer of
  that layer's router; slot K stays all-zero (dummy)
- I32 id->slot tables, one device copy (get_rows remaps ids for a second
  mul_mat_id chain over the cache) and one host copy (src[3] of the CPU
  mul_mat_id, which skips cached ids and zeroes their dst rows)
- the two down outputs are summed; the split is exact by construction
- decode-only (n_tokens == 1); batch/prefill builds the stock graph
- throttled async uploads: evictions are published at a decode-boundary sync
  point, slices are copied by a worker thread, and the new mapping is only
  published after the upload completed, so a running graph never reads a torn
  slot

Enable with LLAMA_MOE_CACHE_SLOTS=<K> (+ LLAMA_MOE_CACHE_INSERTS, _DEBUG).
Inert without the env var.

Measured decode, this box (2x3090, 1 RAM channel/socket, with numactl
--interleave=all): 15.5 -> 19-20 tok/s warm at K=48-64.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01A7KRyLzuBiGfVn3bdczjka
2026-09-21 20:46:03 +03:00
2026-06-12 15:53:26 +02:00
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:

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
S
Description
llama.cpp fork with AVX1, NUMA, SM75 Turing, and FastMTP optimizations
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