# llama.cpp for SYCL

- [Background](#background)
- [Recommended Release](#recommended-release)
- [News](#news)
- [OS](#os)
- [Hardware](#hardware)
- [Performance Reference](#performance-reference)
- [Docker](#docker)
- [Linux](#linux)
- [Windows](#windows-1)
- [Environment Variable](#environment-variable)
- [Design Rule](#design-rule)
- [Known Issue](#known-issues)
- [Q&A](#qa)
- [TODO](#todo)

## Background

**SYCL** is a high-level parallel programming model designed to improve developers productivity writing code across various hardware accelerators such as CPUs, GPUs, and FPGAs. It is a single-source language designed for heterogeneous computing and based on standard C++17.

**oneAPI** is an open ecosystem and a standard-based specification, supporting multiple architectures including but not limited to Intel CPUs, GPUs and FPGAs. The key components of the oneAPI ecosystem include:

- **DPCPP** *(Data Parallel C++)*: The primary oneAPI SYCL implementation, which includes the icpx/icx Compilers.
- **oneAPI Libraries**: A set of highly optimized libraries targeting multiple domains *(e.g. Intel oneMKL, oneMath and oneDNN)*.
- **oneAPI LevelZero**: A high performance low level interface for fine-grained control over Intel iGPUs and dGPUs.

### Llama.cpp + SYCL

The llama.cpp SYCL backend is primarily designed for **Intel GPUs**.
SYCL cross-platform capabilities enable support for other vendor GPUs as well.

## Recommended Release

### Windows

The following releases are verified and recommended:

|Commit ID|Tag|Release|Verified  Platform| Update date|
|-|-|-|-|-|
|24e86cae7219b0f3ede1d5abdf5bf3ad515cccb8|b5377 |[llama-b5377-bin-win-sycl-x64.zip](https://github.com/ggml-org/llama.cpp/releases/download/b5377/llama-b5377-bin-win-sycl-x64.zip) |Arc B580/Linux/oneAPI 2025.1<br>LNL Arc GPU/Windows 11/oneAPI 2025.1.1|2025-05-15|
|3bcd40b3c593d14261fb2abfabad3c0fb5b9e318|b4040 |[llama-b4040-bin-win-sycl-x64.zip](https://github.com/ggml-org/llama.cpp/releases/download/b4040/llama-b4040-bin-win-sycl-x64.zip) |Arc A770/Linux/oneAPI 2024.1<br>MTL Arc GPU/Windows 11/oneAPI 2024.1| 2024-11-19|
|fb76ec31a9914b7761c1727303ab30380fd4f05c|b3038 |[llama-b3038-bin-win-sycl-x64.zip](https://github.com/ggml-org/llama.cpp/releases/download/b3038/llama-b3038-bin-win-sycl-x64.zip) |Arc A770/Linux/oneAPI 2024.1<br>MTL Arc GPU/Windows 11/oneAPI 2024.1||

### Ubuntu 24.04

The release packages for Ubuntu 24.04 x64 (FP32/FP16) only include the binary files of the llama.cpp SYCL backend. They require the target machine to have pre-installed Intel GPU drivers and oneAPI packages that are the same version as the build package. To get the version and installation info, refer to [.github/workflows/release.yml#L713](../../.github/workflows/release.yml#L713): ubuntu-24-sycl -> Download & Install oneAPI.

It is recommended to use them with [Intel Docker](https://hub.docker.com/r/intel/deep-learning-essentials).

The packages for FP32 and FP16 would have different accuracy and performance on LLMs. Please choose it according to the test result.

## News

- 2026.04-05
  - Optimize mul_mat by reorder feature for data type: Q4_K, Q5_K, Q6_K, Q8_0.
  - Fused MoE.
  - Upgrate CI and built package for oneAPI 2025.3.3, support Ubuntu 24.04 built package.

- 2026.03
  - Support Flash-Attention: less memory usage, performance impact depends on LLM.

- 2026.02
  - Remove support for Nvidia & AMD GPU, because the oneAPI plugin for Nvidia & AMD GPU is unavailable: download/installation channels are out of work. User can't build up the software for Nvidia & AMD GPU.

- 2025.11
  - Support malloc memory on device more than 4GB.

- 2025.2
  - Optimize MUL_MAT Q4_0 on Intel GPU for all dGPUs and built-in GPUs since MTL. Increase the performance of LLM (llama-2-7b.Q4_0.gguf) 21%-87% on Intel GPUs (MTL, ARL-H, Arc, Flex, PVC).
    |GPU|Base tokens/s|Increased tokens/s|Percent|
    |-|-|-|-|
    |PVC 1550|39|73|+87%|
    |Flex 170|39|50|+28%|
    |Arc A770|42|55|+30%|
    |MTL|13|16|+23%|
    |ARL-H|14|17|+21%|

- 2024.11
  - Use syclcompat to improve the performance on some platforms. This requires to use oneAPI 2025.0 or newer.

- 2024.8
  - Use oneDNN as the default GEMM library, improve the compatibility for new Intel GPUs.

- 2024.5
  - Performance is increased: 34 -> 37 tokens/s of llama-2-7b.Q4_0 on Arc A770.
  - Arch Linux is verified successfully.

- 2024.4
  - Support data types: GGML_TYPE_IQ4_NL, GGML_TYPE_IQ4_XS, GGML_TYPE_IQ3_XXS, GGML_TYPE_IQ3_S, GGML_TYPE_IQ2_XXS, GGML_TYPE_IQ2_XS, GGML_TYPE_IQ2_S, GGML_TYPE_IQ1_S, GGML_TYPE_IQ1_M.

- 2024.3
  - Release binary files of Windows.
  - A blog is published: **Run LLM on all Intel GPUs Using llama.cpp**: [intel.com](https://www.intel.com/content/www/us/en/developer/articles/technical/run-llm-on-all-gpus-using-llama-cpp-artical.html) or [medium.com](https://medium.com/@jianyu_neo/run-llm-on-all-intel-gpus-using-llama-cpp-fd2e2dcbd9bd).
  - New base line is ready: [tag b2437](https://github.com/ggml-org/llama.cpp/tree/b2437).
  - Support multiple cards: **--split-mode**: [none|layer]; not support [row], it's on developing.
  - Support to assign main GPU by **--main-gpu**, replace $GGML_SYCL_DEVICE.
  - Support detecting all GPUs with level-zero and same top **Max compute units**.
  - Support OPs
    - hardsigmoid
    - hardswish
    - pool2d

- 2024.1
  - Create SYCL backend for Intel GPU.
  - Support Windows build

## OS

| OS      | Status  | Verified                                       |
|---------|---------|------------------------------------------------|
| Linux   | Support | Ubuntu 22.04, Fedora Silverblue 39, Arch Linux |
| Windows | Support | Windows 11                                     |


## Hardware

### Intel GPU

SYCL backend supports Intel GPU Family:

- Intel Data Center Max Series
- Intel Flex Series, Arc Series
- Intel Built-in Arc GPU
- Intel iGPU in Core CPU (11th Generation Core CPU and newer, refer to [oneAPI supported GPU](https://www.intel.com/content/www/us/en/developer/articles/system-requirements/intel-oneapi-base-toolkit-system-requirements.html#inpage-nav-1-1)).

On older Intel GPUs, you may try [OpenCL](/docs/backend/OPENCL.md) although the performance is not optimal, and some GPUs may not support OpenCL nor have any GPGPU capabilities.

#### Verified devices

| Intel GPU                     | Status  | Verified Model                        |
|-------------------------------|---------|---------------------------------------|
| Intel Data Center Max Series  | Support | Max 1550, 1100                        |
| Intel Data Center Flex Series | Support | Flex 170                              |
| Intel Arc A-Series            | Support | Arc A770, Arc A730M, Arc A750         |
| Intel Arc B-Series            | Support | Arc B580                              |
| Intel built-in Arc GPU        | Support | built-in Arc GPU in Meteor Lake, Arrow Lake, Lunar Lake |
| Intel iGPU                    | Support | iGPU in 13700k, 13400, i5-1250P, i7-1260P, i7-1165G7  |

*Notes:*

- **Memory**
  - The device memory is a limitation when running a large model. The loaded model size, *`llm_load_tensors: buffer_size`*, is displayed in the log when running `./bin/llama-completion`.
  - Please make sure the GPU shared memory from the host is large enough to account for the model's size. For e.g. the *llama-2-7b.Q4_0* requires at least 8.0GB for integrated GPU and 4.0GB for discrete GPU.

- **Execution Unit (EU)**
  - If the iGPU has less than 80 EUs, the inference speed will likely be too slow for practical use.

### Other Vendor GPU

NA

## Performance Reference


To get the supported LLMs, GPUs, and performance reference, please check [Performance of llama.cpp on Intel GPU with SYCL backend](https://github.com/ggml-org/llama.cpp/discussions/23313).

You could update your test result in it directly.

## Docker

Please refer to [Docker with SYCL](../docker.md#docker-with-sycl) for details.

## Quick Development WOW

This chapter is for quick development & try with SYCL backend on Intel GPU.

You need to install following sofeware before development:
   - Intel GPU driver
   - oneAPI package
   - other development tools.

Please refer to [Linux](#linux) or [Windows](#windows-1) for above installation and resolve the trouble in usage. There are the detailed guide.

- Linux

```
## build from source code
./examples/sycl/build.sh

## run CONV_2D_DW unit test cases
./build/bin/test-backend-ops -b SYCL0 -o CONV_2D_DW

## run all unit test cases
./build/bin/test-backend-ops -b SYCL0

## run with LLM on the first GPU
./examples/sycl/test.sh -mg 0 -m xxxx.gguf

## run service with LLM on the first GPU
export ONEAPI_DEVICE_SELECTOR="level_zero:0"
./examples/sycl/start-svr.sh -m xxxx.gguf

## update the docs/ops.md for new/update OPs
./examples/sycl/update-ops-doc.sh
```

- Windows

```
## build from source code
examples\sycl\win-build-sycl.bat

## run CONV_2D_DW unit test cases
build\bin\test-backend-ops.exe -b SYCL0 -o CONV_2D_DW

## run all unit test cases
build\bin\test-backend-ops.exe -b SYCL0

## run LLM on the first GPU
examples\sycl\win-test.bat -mg 0 -m xxxx.gguf

## run service with LLM on the first GPU
set ONEAPI_DEVICE_SELECTOR="level_zero:0"
examples\sycl\win-start-svr.bat -m xxxx.gguf

## update the docs/ops.md for new/update OPs
examples\sycl\win-update-ops-doc.bat
```


## Linux

### I. Setup Environment

1. **Install GPU drivers**

  - **Intel GPU**

Intel data center GPUs drivers installation guide and download page can be found here: [Get Intel dGPU Drivers](https://dgpu-docs.intel.com/driver/installation.html#ubuntu-install-steps).

*Note*: for client GPUs *(iGPU & Arc A-Series)*, please refer to the [client iGPU driver installation](https://dgpu-docs.intel.com/driver/client/overview.html).

Once installed, add the user(s) to the `video` and `render` groups.

```sh
sudo usermod -aG render $USER
sudo usermod -aG video $USER
```

*Note*: logout/re-login for the changes to take effect.

Verify installation through `clinfo`:

```sh
sudo apt install clinfo
sudo clinfo -l
```

Sample output:

```sh
Platform #0: Intel(R) OpenCL Graphics
 `-- Device #0: Intel(R) Arc(TM) A770 Graphics

Platform #0: Intel(R) OpenCL HD Graphics
 `-- Device #0: Intel(R) Iris(R) Xe Graphics [0x9a49]
```

2. **Install Intel® oneAPI Base toolkit**

SYCL backend depends on:
  - Intel® oneAPI DPC++/C++ compiler/running-time.
  - Intel® oneAPI DPC++/C++ library (oneDPL).
  - Intel® oneAPI Deep Neural Network Library (oneDNN).
  - Intel® oneAPI Math Kernel Library (oneMKL).

- **For Intel GPU**

All above are included in both **Intel® oneAPI Base toolkit** and **Intel® Deep Learning Essentials** packages.

It's recommended to install **Intel® Deep Learning Essentials** which only provides the necessary libraries with less size.

The **Intel® oneAPI Base toolkit** and **Intel® Deep Learning Essentials** can be obtained from the official [Intel® oneAPI Base Toolkit](https://www.intel.com/content/www/us/en/developer/tools/oneapi/base-toolkit.html) page.

Please follow the instructions for downloading and installing the Toolkit for Linux, and preferably keep the default installation values unchanged, notably the installation path *(`/opt/intel/oneapi` by default)*.

Following guidelines/code snippets assume the default installation values. Otherwise, please make sure the necessary changes are reflected where applicable.

Upon a successful installation, SYCL is enabled for the available Intel devices, along with relevant libraries such as oneAPI oneDNN for Intel GPUs.

|Verified release|
|-|
|2025.3.3 |
|2025.2.1|
|2025.1|
|2024.1|

3. **Verify installation and environment**

In order to check the available SYCL devices on the machine, please use the `sycl-ls` command.
```sh
source /opt/intel/oneapi/setvars.sh
sycl-ls
```

- **Intel GPU**

When targeting an intel GPU, the user should expect one or more devices among the available SYCL devices. Please make sure that at least one GPU is present via `sycl-ls`, for instance `[level_zero:gpu]` in the sample output below:

```
[level_zero:gpu][level_zero:0] Intel(R) oneAPI Unified Runtime over Level-Zero, Intel(R) Arc(TM) A770 Graphics 12.55.8 [1.3.29735+27]
[level_zero:gpu][level_zero:1] Intel(R) oneAPI Unified Runtime over Level-Zero, Intel(R) UHD Graphics 730 12.2.0 [1.3.29735+27]
[opencl:cpu][opencl:0] Intel(R) OpenCL, 13th Gen Intel(R) Core(TM) i5-13400 OpenCL 3.0 (Build 0) [2025.20.8.0.06_160000]
[opencl:gpu][opencl:1] Intel(R) OpenCL Graphics, Intel(R) Arc(TM) A770 Graphics OpenCL 3.0 NEO  [24.39.31294]
[opencl:gpu][opencl:2] Intel(R) OpenCL Graphics, Intel(R) UHD Graphics 730 OpenCL 3.0 NEO  [24.39.31294]
```

### II. Build llama.cpp

#### Intel GPU

```sh
# Uses FP32, consider using FP16 for better performance in most cases
./examples/sycl/build.sh
```

or

```sh
# Export relevant ENV variables
source /opt/intel/oneapi/setvars.sh

# Option 1: Use FP16 (recommended for better performance in most cases)
cmake -B build -DGGML_SYCL=ON -DCMAKE_C_COMPILER=icx -DCMAKE_CXX_COMPILER=icpx -DGGML_SYCL_F16=ON

# Option 2: Use FP32
cmake -B build -DGGML_SYCL=ON -DCMAKE_C_COMPILER=icx -DCMAKE_CXX_COMPILER=icpx

# build all binary
cmake --build build --config Release -j -v
```

It is possible to come across some precision issues when running tests that stem from using faster
instructions, which can be circumvented by setting the environment variable `SYCL_PROGRAM_COMPILE_OPTIONS`
as `-cl-fp32-correctly-rounded-divide-sqrt`

### III. Run the inference

#### Retrieve and prepare model

You can refer to the general [*Obtaining and quantizing models*](../../README.md#obtaining-and-quantizing-models) guide for model preparation, or download an already quantized model like [llama-2-7b.Q4_0.gguf](https://huggingface.co/TheBloke/Llama-2-7B-GGUF/resolve/main/llama-2-7b.Q4_0.gguf?download=true) or [Meta-Llama-3-8B-Instruct-Q4_0.gguf](https://huggingface.co/aptha/Meta-Llama-3-8B-Instruct-Q4_0-GGUF/resolve/main/Meta-Llama-3-8B-Instruct-Q4_0.gguf).

##### Check device

1. Enable oneAPI running environment

```sh
source /opt/intel/oneapi/setvars.sh
```

2. List devices information

Similar to the native `sycl-ls`, available SYCL devices can be queried as follow:

```sh
./build/bin/llama-ls-sycl-device
```

This command will only display the selected backend that is supported by SYCL. The default backend is level_zero. For example, in a system with 2 *Intel GPU* it would look like the following:
```
found 2 SYCL devices:

|  |                  |                                             |Compute   |Max compute|Max work|Max sub|               |
|ID|       Device Type|                                         Name|capability|units      |group   |group  |Global mem size|
|--|------------------|---------------------------------------------|----------|-----------|--------|-------|---------------|
| 0|[level_zero:gpu:0]|               Intel(R) Arc(TM) A770 Graphics|       1.3|        512|    1024|     32|    16225243136|
| 1|[level_zero:gpu:1]|                    Intel(R) UHD Graphics 770|       1.3|         32|     512|     32|    53651849216|
```

#### Choose level-zero devices

|Chosen Device ID|Setting|
|-|-|
|0|`export ONEAPI_DEVICE_SELECTOR="level_zero:0"` or no action|
|1|`export ONEAPI_DEVICE_SELECTOR="level_zero:1"`|
|0 & 1|`export ONEAPI_DEVICE_SELECTOR="level_zero:0;level_zero:1"`|

#### Execute

Choose one of following methods to run.

1. Script

- Use device 0:

```sh
./examples/sycl/test.sh -mg 0
```
- Use multiple devices:

```sh
./examples/sycl/test.sh
```

- Run llama-server:

```sh
./examples/sycl/start-svr.sh -m PATH/MODEL_FILE
```

2. Command line
Launch inference

There are two device selection modes:

- Single device: Use one device assigned by user. Default device id is 0.
- Multiple devices: Automatically choose the devices with the same backend.

In two device selection modes, the default SYCL backend is level_zero, you can choose other backend supported by SYCL by setting environment variable ONEAPI_DEVICE_SELECTOR.

| Device selection | Parameter                              |
|------------------|----------------------------------------|
| Single device    | --split-mode none --main-gpu DEVICE_ID |
| Multiple devices | --split-mode layer (default)           |
| Multiple devices | --split-mode tensor (tensor parallelism) |

`--split-mode tensor` (tensor parallelism) shards each layer across the selected
GPUs. It requires flash attention, which is auto-enabled when `--flash-attn` is
left at its default `auto`, so `--split-mode tensor` works out of the box.
Passing `--flash-attn off` together with `--split-mode tensor` is rejected at
context creation. The default `f16` KV cache is recommended. Tensor parallelism
is currently optimized for 2 GPUs; other device counts fall back to a generic
all-reduce.

Examples:

- Use device 0:

```sh
ZES_ENABLE_SYSMAN=1 ./build/bin/llama-completion -no-cnv -m models/llama-2-7b.Q4_0.gguf -p "Building a website can be done in 10 simple steps:" -n 400 -e -ngl 99 -sm none -mg 0 --mmap
```

- Use multiple devices:

```sh
ZES_ENABLE_SYSMAN=1 ./build/bin/llama-completion -no-cnv -m models/llama-2-7b.Q4_0.gguf -p "Building a website can be done in 10 simple steps:" -n 400 -e -ngl 99 -sm layer --mmap
```

*Notes:*

- Upon execution, verify the selected device(s) ID(s) in the output log, which can for instance be displayed as follow:

```sh
detect 1 SYCL GPUs: [0] with top Max compute units:512
```
Or
```sh
use 1 SYCL GPUs: [0] with Max compute units:512
```

## Windows

### Install GPU driver

Intel GPU drivers instructions guide and download page can be found here: [Get Intel GPU Drivers](https://www.intel.com/content/www/us/en/products/docs/discrete-gpus/arc/software/drivers.html).

### Option 1: download the binary package directly

Download the binary package for Windows from: https://github.com/ggml-org/llama.cpp/releases.

Extract the package to local folder, run the llama tools directly. Refer to [Run the inference](#iii-run-the-inference-1).

Note, the package includes the SYCL running time and all depended dll files, no need to install oneAPI package and activte them.

### Option 2: build locally from the source code.

#### I. Setup environment

1. Install Visual Studio

If you already have a recent version of Microsoft Visual Studio, you can skip this step. Otherwise, please refer to the official download page for [Microsoft Visual Studio](https://visualstudio.microsoft.com/).

2. Install Intel® oneAPI Base toolkit

SYCL backend depends on:
  - Intel® oneAPI DPC++/C++ compiler/running-time.
  - Intel® oneAPI DPC++/C++ library (oneDPL).
  - Intel® oneAPI Deep Neural Network Library (oneDNN).
  - Intel® oneAPI Math Kernel Library (oneMKL).

All above are included in both **Intel® oneAPI Base toolkit** and **Intel® Deep Learning Essentials** packages.

It's recommended to install **Intel® Deep Learning Essentials** which only provides the necessary libraries with less size.

The **Intel® oneAPI Base toolkit** and **Intel® Deep Learning Essentials** can be obtained from the official [Intel® oneAPI Base Toolkit](https://www.intel.com/content/www/us/en/developer/tools/oneapi/base-toolkit.html) page.

Please follow the instructions for downloading and installing the Toolkit for Windows, and preferably keep the default installation values unchanged, notably the installation path *(`C:\Program Files (x86)\Intel\oneAPI` by default)*.

Following guidelines/code snippets assume the default installation values. Otherwise, please make sure the necessary changes are reflected where applicable.

b. Enable oneAPI running environment:

- Type "oneAPI" in the search bar, then open the `Intel oneAPI command prompt for Intel 64 for Visual Studio 2022` App.

- On the command prompt, enable the runtime environment with the following:
```
"C:\Program Files (x86)\Intel\oneAPI\setvars.bat" intel64
```

- if you are using Powershell, enable the runtime environment with the following:

```
cmd.exe "/K" '"C:\Program Files (x86)\Intel\oneAPI\setvars.bat" && powershell'
```

c. Verify installation

In the oneAPI command line, run the following to print the available SYCL devices:

```
sycl-ls.exe
```

There should be one or more *level-zero* GPU devices displayed as **[ext_oneapi_level_zero:gpu]**. Below is example of such output detecting an *Intel Iris Xe* GPU as a Level-zero SYCL device:

Output (example):
```
[opencl:acc:0] Intel(R) FPGA Emulation Platform for OpenCL(TM), Intel(R) FPGA Emulation Device OpenCL 1.2  [2023.16.10.0.17_160000]
[opencl:cpu:1] Intel(R) OpenCL, 11th Gen Intel(R) Core(TM) i7-1185G7 @ 3.00GHz OpenCL 3.0 (Build 0) [2023.16.10.0.17_160000]
[opencl:gpu:2] Intel(R) OpenCL Graphics, Intel(R) Iris(R) Xe Graphics OpenCL 3.0 NEO  [31.0.101.5186]
[ext_oneapi_level_zero:gpu:0] Intel(R) Level-Zero, Intel(R) Iris(R) Xe Graphics 1.3 [1.3.28044]
```

3. Install build tools

a. Download & install cmake for Windows: https://cmake.org/download/ (CMake can also be installed from Visual Studio Installer)
b. The new Visual Studio will install Ninja as default. (If not, please install it manually: https://ninja-build.org/)


#### II. Build llama.cpp

You could download the release package for Windows directly, which including binary files and depended oneAPI dll files.

Choose one of following methods to build from source code.

##### Option 1: Script

```sh
# Uses FP32, consider using FP16 for better performance in most cases
.\examples\sycl\win-build-sycl.bat
```

##### Option 2: CMake

On the oneAPI command line window, step into the llama.cpp main directory and run the following:

```
@call "C:\Program Files (x86)\Intel\oneAPI\setvars.bat" intel64 --force

# Option 1: Use FP16 (recommended for better performance in most cases)
cmake -B build -G "Ninja" -DGGML_SYCL=ON -DCMAKE_C_COMPILER=cl -DCMAKE_CXX_COMPILER=icx -DCMAKE_BUILD_TYPE=Release -DGGML_SYCL_F16=ON

# Option 2: Or FP32
cmake -B build -G "Ninja" -DGGML_SYCL=ON -DCMAKE_C_COMPILER=cl -DCMAKE_CXX_COMPILER=icx -DCMAKE_BUILD_TYPE=Release

cmake --build build --config Release -j
```

Or, use CMake presets to build:

```sh
cmake -DGGML_SYCL_F16=ON --preset x64-windows-sycl-release
cmake --build build-x64-windows-sycl-release -j --target llama-completion

cmake --preset x64-windows-sycl-release
cmake --build build-x64-windows-sycl-release -j --target llama-completion

cmake --preset x64-windows-sycl-debug
cmake --build build-x64-windows-sycl-debug -j --target llama-completion
```

##### Option 3: Visual Studio

You have two options to use Visual Studio to build llama.cpp:
- As CMake Project using CMake presets.
- Creating a Visual Studio solution to handle the project.

**Note**:

All following commands are executed in PowerShell.

###### - Open as a CMake Project

You can use Visual Studio to open the `llama.cpp` folder directly as a CMake project. Before compiling, select one of the SYCL CMake presets:

- `x64-windows-sycl-release`

- `x64-windows-sycl-debug`

*Notes:*
- For a minimal experimental setup, you can build only the inference executable using:

    ```Powershell
    cmake --build build --config Release -j --target llama-completion
    ```

###### - Generating a Visual Studio Solution

You can use Visual Studio solution to build and work on llama.cpp on Windows. You need to convert the CMake Project into a `.sln` file.

If you want to use the Intel C++ Compiler for the entire `llama.cpp` project, run the following command:

```Powershell
cmake -B build -G "Visual Studio 17 2022" -T "Intel C++ Compiler 2025" -A x64 -DGGML_SYCL=ON -DCMAKE_BUILD_TYPE=Release
```

If you prefer to use the Intel C++ Compiler only for `ggml-sycl`, ensure that `ggml` and its backend libraries are built as shared libraries ( i.e. `-DBUILD_SHARED_LIBRARIES=ON`, this is default behaviour):

```Powershell
cmake -B build -G "Visual Studio 17 2022" -A x64 -DGGML_SYCL=ON -DCMAKE_BUILD_TYPE=Release \
      -DSYCL_INCLUDE_DIR="C:\Program Files (x86)\Intel\oneAPI\compiler\latest\include" \
      -DSYCL_LIBRARY_DIR="C:\Program Files (x86)\Intel\oneAPI\compiler\latest\lib"
```

If successful the build files have been written to: *path/to/llama.cpp/build*
Open the project file **build/llama.cpp.sln** with Visual Studio.

Once the Visual Studio solution is created, follow these steps:

1. Open the solution in Visual Studio.

2. Right-click on `ggml-sycl` and select **Properties**.

3. In the left column, expand **C/C++** and select **DPC++**.

4. In the right panel, find **Enable SYCL Offload** and set it to `Yes`.

5. Apply the changes and save.


*Navigation Path:*

```
Properties -> C/C++ -> DPC++ -> Enable SYCL Offload (Yes)
```

Now, you can build `llama.cpp` with the SYCL backend as a Visual Studio project.
To do it from menu: `Build -> Build Solution`.
Once it is completed, final results will be in **build/Release/bin**

*Additional Note*

- You can avoid specifying `SYCL_INCLUDE_DIR` and `SYCL_LIBRARY_DIR` in the CMake command by setting the environment variables:

    - `SYCL_INCLUDE_DIR_HINT`

    - `SYCL_LIBRARY_DIR_HINT`

- Above instruction has been tested with Visual Studio 17 Community edition and oneAPI 2025.0. We expect them to work also with future version if the instructions are adapted accordingly.

### III. Run the inference

#### Retrieve and prepare model

You can refer to the general [*Obtaining and quantizing models*](../../README.md#obtaining-and-quantizing-models) guide for model preparation, or download an already quantized model like [llama-2-7b.Q4_0.gguf](https://huggingface.co/TheBloke/Llama-2-7B-GGUF/blob/main/llama-2-7b.Q4_0.gguf) or [Meta-Llama-3-8B-Instruct-Q4_0.gguf](https://huggingface.co/aptha/Meta-Llama-3-8B-Instruct-Q4_0-GGUF/resolve/main/Meta-Llama-3-8B-Instruct-Q4_0.gguf).

##### Check device

1. Enable oneAPI running environment

On the oneAPI command line window, run the following and step into the llama.cpp directory:
```
"C:\Program Files (x86)\Intel\oneAPI\setvars.bat" intel64
```

2. List devices information

Similar to the native `sycl-ls`, available SYCL devices can be queried as follow:

```
build\bin\llama-ls-sycl-device.exe
```

This command will only display the selected backend that is supported by SYCL. The default backend is level_zero. For example, in a system with 2 *Intel GPU* it would look like the following:
```
found 2 SYCL devices:
|  |                  |                                             |Compute   |Max compute|Max work|Max sub|               |
|ID|       Device Type|                                         Name|capability|units      |group   |group  |Global mem size|
|--|------------------|---------------------------------------------|----------|-----------|--------|-------|---------------|
| 0|[level_zero:gpu:0]|               Intel(R) Arc(TM) A770 Graphics|       1.3|        512|    1024|     32|    16225243136|
| 1|[level_zero:gpu:1]|                    Intel(R) UHD Graphics 770|       1.3|         32|     512|     32|    53651849216|

```

##### Choose level-zero devices

|Chosen Device ID|Setting|
|-|-|
|0|Default option. You may also want to `set ONEAPI_DEVICE_SELECTOR="level_zero:0"`|
|1|`set ONEAPI_DEVICE_SELECTOR="level_zero:1"`|
|0 & 1|`set ONEAPI_DEVICE_SELECTOR="level_zero:0;level_zero:1"` or `set ONEAPI_DEVICE_SELECTOR="level_zero:*"`|

##### Execute

Choose one of following methods to run.

1. Script

- Run test:

```
examples\sycl\win-test.bat
```

- Run llama-server:

```
examples\sycl\win-start-svr.bat -m PATH\MODEL_FILE
```

2. Command line

Launch inference

There are two device selection modes:

- Single device: Use one device assigned by user. Default device id is 0.
- Multiple devices: Automatically choose the devices with the same backend.

In two device selection modes, the default SYCL backend is level_zero, you can choose other backend supported by SYCL by setting environment variable ONEAPI_DEVICE_SELECTOR.

| Device selection | Parameter                              |
|------------------|----------------------------------------|
| Single device    | --split-mode none --main-gpu DEVICE_ID |
| Multiple devices | --split-mode layer (default)           |
| Multiple devices | --split-mode tensor (tensor parallelism) |

`--split-mode tensor` (tensor parallelism) shards each layer across the selected
GPUs. It requires flash attention, which is auto-enabled when `--flash-attn` is
left at its default `auto`, so `--split-mode tensor` works out of the box.
Passing `--flash-attn off` together with `--split-mode tensor` is rejected at
context creation. The default `f16` KV cache is recommended. Tensor parallelism
is currently optimized for 2 GPUs; other device counts fall back to a generic
all-reduce.

Examples:

- Use device 0:

```
build\bin\llama-completion.exe -no-cnv -m models\llama-2-7b.Q4_0.gguf -p "Building a website can be done in 10 simple steps:\nStep 1:" -n 400 -e -ngl 99 -sm none -mg 0 --mmap
```

- Use multiple devices:

```
build\bin\llama-completion.exe -no-cnv -m models\llama-2-7b.Q4_0.gguf -p "Building a website can be done in 10 simple steps:\nStep 1:" -n 400 -e -ngl 99 -sm layer --mmap
```


Note:

- Upon execution, verify the selected device(s) ID(s) in the output log, which can for instance be displayed as follow:

```sh
detect 1 SYCL GPUs: [0] with top Max compute units:512
```

Or

```sh
use 1 SYCL GPUs: [0] with Max compute units:512
```


## Environment Variable

### Build

| Name               | Value                                 | Function                                    |
|--------------------|---------------------------------------|---------------------------------------------|
| GGML_SYCL          | ON (mandatory)                        | Enable build with SYCL code path.           |
| GGML_SYCL_TARGET   | INTEL *(default)*                     | Set the SYCL target device type.            |
| GGML_SYCL_DEVICE_ARCH | Optional                           | Set the SYCL device architecture. Setting the device architecture can improve the performance. See the table [--offload-arch](https://github.com/intel/llvm/blob/sycl/sycl/doc/design/OffloadDesign.md#--offload-arch) for a list of valid architectures. |
| GGML_SYCL_F16      | OFF *(default)* \|ON *(optional)*     | Enable FP16 build with SYCL code path. (1.) |
| GGML_SYCL_GRAPH    | ON *(default)* \|OFF *(Optional)*     | Enable build with [SYCL Graph extension](https://github.com/intel/llvm/blob/sycl/sycl/doc/extensions/experimental/sycl_ext_oneapi_graph.asciidoc). |
| GGML_SYCL_DNN      | ON *(default)* \|OFF *(Optional)*     | Enable build with oneDNN.                   |
| GGML_SYCL_HOST_MEM_FALLBACK | ON *(default)* \|OFF *(Optional)* | Allow host memory fallback when device memory is full during quantized weight reorder. Enables inference to continue at reduced speed (reading over PCIe) instead of failing. Requires Linux kernel 6.8+. |
| GGML_SYCL_SUPPORT_LEVEL_ZERO_API | ON *(default)* \|OFF *(Optional)* | Support to use Level Zero API for device memory allocation. Requires Level Zero headers/library at build time and Intel GPU driver (Level Zero runtime) at run time. Reduces system RAM usage during multi-GPU inference. SYCL backend always runs on Level Zero running time even if it's set as OFF (The SYCL api will be usage for memory allocation).|
| CMAKE_C_COMPILER   | `icx` *(Linux)*, `icx/cl` *(Windows)* | Set `icx` compiler for SYCL code path.      |
| CMAKE_CXX_COMPILER | `icpx` *(Linux)*, `icx` *(Windows)*   | Set `icpx/icx` compiler for SYCL code path. |

1. FP32 or FP16 have different performance impact to LLM. Recommended to test them for better prompt processing performance on your models. You need to rebuild the code after change `GGML_SYCL_F16=OFF/ON`.

### Runtime

| Name              | Value            | Function                                                                                                                  |
|-------------------|------------------|---------------------------------------------------------------------------------------------------------------------------|
| GGML_SYCL_DEBUG   | 0 (default) or 1 | Enable log function by macro: GGML_SYCL_DEBUG                                                                             |
| GGML_SYCL_DEV2DEV_MEMCPY | 0 (default), 1, 2 | Choose the method of dev2dev memory copy.<br>Value: <br>*  0: SYCL API (default), only support dGPUs.<br>* 1: L0 API -- Better performance, only support dGPUs, found to lead to abnormal crash in some case. <br>* 2: Host Forward -- Most stable method for all cases (including iGPU + dGPU*N), but with lower performance (-2% to -5%).<br>SYCL & L0 API are easy to be impacted by Intel GPU driver issue. When you meet the garbled output or crash issues in multiple GPUs case, try with this debug flag to work around or check the issue.|
| GGML_SYCL_ENABLE_FLASH_ATTN | 1 (default) or 0| Enable Flash-Attention. It can reduce memory usage. The performance impact depends on the LLM.|
| GGML_SYCL_ENABLE_OPT | 0 or 1 (default)| Enable optimize features for Intel GPUs. (Recommended to 0 for Intel devices older than Gen 10) |
| GGML_SYCL_ENABLE_GRAPH | 0 (default) or 1 | Enable running computations through SYCL Graphs feature. Disabled by default because SYCL Graph is still on development, no better performance. |
| GGML_SYCL_USE_LEVEL_ZERO_API | 1 (default) or 0 | Use Level Zero API for device memory allocation instead of SYCL. Reduces system RAM usage on Intel dGPUs by avoiding DMA-buf/TTM host memory staging. Requires GGML_SYCL_SUPPORT_LEVEL_ZERO_API=ON at build time. SYCL backend always runs on Level Zero running time even if it's set as OFF (The SYCL api will be usage for memory allocation).|
| GGML_SYCL_ENABLE_DNN | 0 or 1 (default)| Enable running computations through oneDNN and always use oneMKL. |
| GGML_SYCL_FA_ONEDNN | 1 (default) or 0 | Enable the oneDNN fused SDPA (flash-attention) path on supported GPUs. Set to 0 to always use the native SYCL flash-attention kernel. |
| GGML_SYCL_FA_ONEDNN_MAX_KV | 0 (default, disabled) or positive integer | By default (0), all sequences are handled by the oneDNN fused SDPA path, regardless of KV length; a positive value caps that length, past which sequences fall back to the native kernel. If GPU driver watchdog resets (DEVICE_LOST) occur during long-context inference, set this near the context depth where they start, e.g. 24576. |
| GGML_SYCL_ENABLE_VMM | 0 or 1 (default) | Enable the virtual-memory device pool. |
| GGML_SYCL_ENABLE_MKL_FA | 1 (default) or 0 | Enable oneMKL GEMM flash attention for XMX-accelerated prompt processing with quantized KV cache. Automatically activates during prefill (prompt processing) when all conditions are met: (1) flash-attn enabled (`-fa` or `--flash-attn on`), (2) KV cache quantized (`--cache-type-k q8_0 --cache-type-v q8_0` or other `*_0/*_1` types), (3) batch size ≥ 1024 (`--batch-size 1024`), (4) prompt length ≥ 1024 tokens. Set to 0 to force the TILE kernel for A/B testing. Example minimum command: `llama-cli -m model.gguf -fa -ngl 99 --cache-type-k q8_0 --cache-type-v q8_0 --batch-size 1024 -p "your prompt"` |
| GGML_SYCL_MKL_FA_DEBUG | 0 (default) or 1 | Enable per-call diagnostic logging for MKL flash attention: GEMM/softmax timings, interleaved-head detection, and buffer memory usage. |
| GGML_SYCL_MKL_FA_DIAG | 0 (default) or 1 | Enable output fingerprinting for MKL flash attention. Dumps the first 64 float output values for the first 6 FA calls with n_kv ≥ 1024, labeled with kernel type (MKL/TILE/VEC) for cross-kernel comparison. |
| GGML_SYCL_ENABLE_FUSION | 0 or 1 (default) | Enable fused-kernel dispatch in graph compute (currently top-k MoE gating). |
| ZES_ENABLE_SYSMAN | 0 (default) or 1 | Support to get free memory of GPU by sycl::aspect::ext_intel_free_memory.<br>Recommended to use when --split-mode = layer |
| UR_L0_ENABLE_RELAXED_ALLOCATION_LIMITS | 0 (default) or 1 | Allow SYCL/Unified Runtime Level Zero device allocations larger than 4 GiB. llama.cpp's direct Level Zero allocation path requests the relaxed maximum-size limit itself when GGML_SYCL_ENABLE_LEVEL_ZERO=1. |
| GGML_SYCL_USM_SYSTEM | 0 (default) or 1 | Enable experimental support for [USM system allocations](https://github.khronos.org/SYCL_Reference/iface/usm_basic_concept.html#system-allocations) for large GPU buffers. This requires enough host memory for model weights and caches, an Intel Xe2+ GPU such as BMG or newer and supported on Linux only, with CONFIG_DRM_XE_GPUSVM enabled. |

## Compile-time Flags

Pass these via `CXXFLAGS` or add a one-off `#define` to enable a flag on the spot.

| Name            | Function                                                                         |
|-----------------|----------------------------------------------------------------------------------|
| DEBUG_SYCL_POOL | Enable device memory pool logging on teardown. Useful for profiling allocations. |
| DEBUG_SYCL_MALLOC | Enable verbose per-call logging of device pool alloc/free operations. |
| GGML_SYCL_SUPPORT_VMM | Support to building with VMM code. Default is Yes. |

## Design Rule

- Open to all contributors.

- All code change should be useful to user:
    - Fix bug.
    - Add new function.
    - Improve the performance/usage.
    - Make code be easy to maintain.
    - ...

- Don't accept the codes of following cases:
    - Break legacy function.
    - Reduce the performance of legacy case in default.
    - Not completed work/the functionality cannot be demonstrated.

- Encourage to use environment variable to control features to be opened/closed.
    - User can evaluate the feature without rebuild the code.
    - Recommend the best features to user by setting them be opened as default.

- Design the code based on the published official releases of oneAPI packages: compiler, library, driver, OS kernel.

- Developers need to maintain the code they submit.

## Known Issues

- `Split-mode:[row]` is not supported.

- Missed the AOT (Ahead-of-Time) in building.
  - Good: Builds quickly, smaller size of binary file.
  - Bad: The startup is slow (JIT) in first time, but subsequent performance is unaffected.

## Q&A

- Error:  `error while loading shared libraries: libsycl.so: cannot open shared object file: No such file or directory`.

  - Potential cause: Unavailable oneAPI installation or not set ENV variables.
  - Solution: Install *oneAPI base toolkit* and enable its ENV through: `source /opt/intel/oneapi/setvars.sh`.

- General compiler error:

  - Remove **build** folder or try a clean-build.

- I can **not** see `[ext_oneapi_level_zero:gpu]` after installing the GPU driver on Linux.

  Please double-check with `sudo sycl-ls`.

  If it's present in the list, please add video/render group to your user then **logout/login** or restart your system:

  ```
  sudo usermod -aG render $USER
  sudo usermod -aG video $USER
  ```
  Otherwise, please double-check the GPU driver installation steps.

- Can I report Ollama issue on Intel GPU to llama.cpp SYCL backend?

  No. We can't support Ollama issue directly, because we aren't familiar with Ollama.

  Suggest reproducing on llama.cpp and report similar issue to llama.cpp. We will support it.

  It's same for other projects including llama.cpp SYCL backend.

- `Native API failed. Native API returns: 39 (UR_RESULT_ERROR_OUT_OF_DEVICE_MEMORY)`, `ggml_backend_sycl_buffer_type_alloc_buffer: can't allocate 3503030272 Bytes of memory on device`, or `failed to allocate SYCL0 buffer`

  You are running out of Device Memory.

  |Reason|Solution|
  |-|-|
  | The default context is too big. It leads to excessive memory usage.|Set `-c 8192` or a smaller value.|
  | The model is too big and requires more memory than what is available.|Choose a smaller model or change to a smaller quantization, like Q5 -> Q4;<br>Alternatively, use more than one device to load model.|

- `ggml_backend_sycl_buffer_type_alloc_buffer: can't allocate 5000000000 Bytes of memory on device`

  With the default `GGML_SYCL_ENABLE_LEVEL_ZERO=1`, llama.cpp requests Level Zero's relaxed maximum-size allocation limit directly. If Level Zero support is disabled at build time or runtime and the allocation goes through SYCL/Unified Runtime instead, enable support for allocations larger than 4 GiB by:
  ```
    export UR_L0_ENABLE_RELAXED_ALLOCATION_LIMITS=1
    set UR_L0_ENABLE_RELAXED_ALLOCATION_LIMITS=1
  ```

### **GitHub contribution**:
Please add the `[SYCL]` prefix/tag in issues/PRs titles to help the SYCL contributors to check/address them without delay.

## TODO

- Review ZES_ENABLE_SYSMAN: https://github.com/intel/compute-runtime/blob/master/programmers-guide/SYSMAN.md#support-and-limitations
