Frosty40 39febd2adb sycl: work-group argmax for short TOP_K rows (#31110)
* sycl: work-group argmax for short TOP_K rows

Used angelX to optimize SYCL/drama 3 coordination, results are as follows

Rows with ncols <= max work-group size: one work-item per column, k rounds of work-group argmax. Ties take the lower column, NaN is never picked. Longer rows keep the existing paths.

Arc Pro B70, oneAPI 2026.1, test-backend-ops perf (existing short-row cases), base 9b56ccf00 vs patch, median ratio of 6 rotating A/B/A rounds:

| ncols | nrows | k | base us | patch us | speedup |
|---|---|---|---|---|---|
| 16 | 1024 | 1 | 19.97 | 2.88 | 6.95x |
| 16 | 1024 | 2 | 23.83 | 2.90 | 8.25x |
| 16 | 1024 | 8 | 66.12 | 4.66 | 14.21x |
| 16 | 8192 | 1 | 110.42 | 5.96 | 18.51x |
| 16 | 8192 | 2 | 130.21 | 8.82 | 14.77x |
| 16 | 8192 | 8 | 420.62 | 27.27 | 15.42x |
| 128 | 1024 | 1 | 20.49 | 2.94 | 6.97x |
| 128 | 1024 | 2 | 25.89 | 3.45 | 7.52x |
| 128 | 1024 | 8 | 101.67 | 8.95 | 11.36x |
| 128 | 8192 | 1 | 112.19 | 13.29 | 8.44x |
| 128 | 8192 | 2 | 141.18 | 20.60 | 6.85x |
| 128 | 8192 | 8 | 643.21 | 67.60 | 9.51x |
| 1024 | 1024 | 1 | 17.32 | 14.98 | 1.16x |
| 1024 | 1024 | 2 | 28.77 | 24.02 | 1.20x |
| 1024 | 1024 | 8 | 151.87 | 77.88 | 1.95x |
| 1024 | 8192 | 1 | 156.49 | 138.78 | 1.13x |
| 1024 | 8192 | 2 | 201.47 | 209.18 | 0.96x |
| 1024 | 8192 | 8 | 1006.25 | 632.60 | 1.59x |

The 1024 x 8192, k=2 case is 3.7% slower.

Correctness: test-backend-ops -o TOP_K 533/533 and -o ARGSORT 98/98 on the patch, again on the rebase onto 3f03b1772.

Full test-backend-ops aborts on base and patch alike at the non-F32 SWIGLU_OAI assert (element_wise.cpp:1187, see #30857). With only those cases excluded: 20145/20173 on base and patch. One CPY f16->q2_0 [256,2,3,4] failure was seen once on the patch, and 3/3 re-runs pass on base and patch. All other patch-run failures also fail on base.

Assisted-by: Claude Opus 5.5

* made changes as suggested

Assisted-by: Claude Opus 5.5
2026-10-28 22:18:07 +08:00
2026-10-28 12:36:51 +02:00
2026-06-12 15:53:26 +02:00
2026-10-17 02:11:56 +02:00
2026-02-02 08:38:55 +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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llama.cpp fork with AVX1, NUMA, SM75 Turing, and FastMTP optimizations
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