opencl: update doc for OpenCL (#12702)

* opencl: add OpenCL to build.md

* opencl: remove fixed issue/TODO

* opencl: add link to OPENCL.md

* opencl: update doc - refine tools requirement for Windows 11 arm64

diff --git a/docs/backend/OPENCL.md b/docs/backend/OPENCL.md
index 2a946dc8df0ff90bd075a937a3c1f82e0f5d91d0..07146f7102f3df1f299e9468dc72f0871767b19b 100644 (file)
--- a/docs/backend/OPENCL.md
+++ b/docs/backend/OPENCL.md
@@ -145,8 +145,13 @@ A Snapdragon X Elite device with Windows 11 Arm64 is used. Make sure the followi
 * Clang 19
 * Ninja
 * Visual Studio 2022
+* Powershell 7
 
-Powershell is used for the following instructions.
+Visual Studio provides necessary headers and libraries although it is not directly used for building.
+Alternatively, Visual Studio Build Tools can be installed instead of the full Visual Studio.
+
+Powershell 7 is used for the following commands.
+If an older version of Powershell is used, these commands may not work as they are.
 
 ### I. Setup Environment
 
@@ -196,10 +201,9 @@ ninja
 
 ## Known Issues
 
-- Qwen2.5 0.5B model produces gibberish output with Adreno kernels.
+- Currently OpenCL backend does not work on Adreno 6xx GPUs.
 
 ## TODO
 
-- Fix Qwen2.5 0.5B
 - Optimization for Q6_K
 - Support and optimization for Q4_K

diff --git a/docs/build.md b/docs/build.md
index 9c1314a29431b44c96107633e384134966646451..3f1b043992545d5b78a324d80028170233bd31f0 100644 (file)
--- a/docs/build.md
+++ b/docs/build.md
@@ -456,6 +456,96 @@ KleidiAI's microkernels implement optimized tensor operations using Arm CPU feat
 
 Depending on your build target, other higher priority backends may be enabled by default. To ensure the CPU backend is used, you must disable the higher priority backends either at compile time, e.g. -DGGML_METAL=OFF, or during run-time using the command line option `--device none`.
 
+## OpenCL
+
+This provides GPU acceleration through OpenCL on recent Adreno GPU.
+More information about OpenCL backend can be found in [OPENCL.md](./backend/OPENCL.md) for more information.
+
+### Android
+
+Assume NDK is available in `$ANDROID_NDK`. First, install OpenCL headers and ICD loader library if not available,
+
+```sh
+mkdir -p ~/dev/llm
+cd ~/dev/llm
+
+git clone https://github.com/KhronosGroup/OpenCL-Headers && \
+cd OpenCL-Headers && \
+cp -r CL $ANDROID_NDK/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/include
+
+cd ~/dev/llm
+
+git clone https://github.com/KhronosGroup/OpenCL-ICD-Loader && \
+cd OpenCL-ICD-Loader && \
+mkdir build_ndk && cd build_ndk && \
+cmake .. -G Ninja -DCMAKE_BUILD_TYPE=Release \
+  -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK/build/cmake/android.toolchain.cmake \
+  -DOPENCL_ICD_LOADER_HEADERS_DIR=$ANDROID_NDK/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/include \
+  -DANDROID_ABI=arm64-v8a \
+  -DANDROID_PLATFORM=24 \
+  -DANDROID_STL=c++_shared && \
+ninja && \
+cp libOpenCL.so $ANDROID_NDK/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/lib/aarch64-linux-android
+```
+
+Then build llama.cpp with OpenCL enabled,
+
+```sh
+cd ~/dev/llm
+
+git clone https://github.com/ggml-org/llama.cpp && \
+cd llama.cpp && \
+mkdir build-android && cd build-android
+
+cmake .. -G Ninja \
+  -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK/build/cmake/android.toolchain.cmake \
+  -DANDROID_ABI=arm64-v8a \
+  -DANDROID_PLATFORM=android-28 \
+  -DBUILD_SHARED_LIBS=OFF \
+  -DGGML_OPENCL=ON
+
+ninja
+```
+
+### Windows Arm64
+
+First, install OpenCL headers and ICD loader library if not available,
+
+```powershell
+mkdir -p ~/dev/llm
+
+cd ~/dev/llm
+git clone https://github.com/KhronosGroup/OpenCL-Headers && cd OpenCL-Headers
+mkdir build && cd build
+cmake .. -G Ninja `
+  -DBUILD_TESTING=OFF `
+  -DOPENCL_HEADERS_BUILD_TESTING=OFF `
+  -DOPENCL_HEADERS_BUILD_CXX_TESTS=OFF `
+  -DCMAKE_INSTALL_PREFIX="$HOME/dev/llm/opencl"
+cmake --build . --target install
+
+cd ~/dev/llm
+git clone https://github.com/KhronosGroup/OpenCL-ICD-Loader && cd OpenCL-ICD-Loader
+mkdir build && cd build
+cmake .. -G Ninja `
+  -DCMAKE_BUILD_TYPE=Release `
+  -DCMAKE_PREFIX_PATH="$HOME/dev/llm/opencl" `
+  -DCMAKE_INSTALL_PREFIX="$HOME/dev/llm/opencl"
+cmake --build . --target install
+```
+
+Then build llama.cpp with OpenCL enabled,
+
+```powershell
+cmake .. -G Ninja `
+  -DCMAKE_TOOLCHAIN_FILE="$HOME/dev/llm/llama.cpp/cmake/arm64-windows-llvm.cmake" `
+  -DCMAKE_BUILD_TYPE=Release `
+  -DCMAKE_PREFIX_PATH="$HOME/dev/llm/opencl" `
+  -DBUILD_SHARED_LIBS=OFF `
+  -DGGML_OPENCL=ON
+ninja
+```
+
 ## Android
 
 To read documentation for how to build on Android, [click here](./android.md)