104 lines
5.7 KiB
Markdown
104 lines
5.7 KiB
Markdown
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# Android
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## Build with Android Studio
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Import the `examples/llama.android` directory into Android Studio, then perform a Gradle sync and build the project.
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This Android binding supports hardware acceleration up to `SME2` for **Arm** and `AMX` for **x86-64** CPUs on Android and ChromeOS devices.
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It automatically detects the host's hardware to load compatible kernels. As a result, it runs seamlessly on both the latest premium devices and older devices that may lack modern CPU features or have limited RAM, without requiring any manual configuration.
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A minimal Android app frontend is included to showcase the binding’s core functionalities:
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1. **Parse GGUF metadata** via `GgufMetadataReader` from either a `ContentResolver` provided `Uri` or a local `File`.
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2. **Obtain a `TierDetection` or `InferenceEngine`** instance through the high-level facade APIs.
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3. **Send a raw user prompt** for automatic template formatting, prefill, and decoding. Then collect the generated tokens in a Kotlin `Flow`.
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For a production-ready experience that leverages advanced features such as system prompts and benchmarks, check out [Arm AI Chat](https://play.google.com/store/apps/details?id=com.arm.aichat) on Google Play.
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This project is made possible through a collaborative effort by Arm's **CT-ML**, **CE-ML** and **STE** groups:
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|  |  |  |
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|:------------------------------------------------------:|:----------------------------------------------------:|:--------------------------------------------------------:|
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| Home screen | System prompt | "Haiku" |
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## Build on Android using Termux
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[Termux](https://termux.dev/en/) is an Android terminal emulator and Linux environment app (no root required). As of writing, Termux is available experimentally in the Google Play Store; otherwise, it may be obtained directly from the project repo or on F-Droid.
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With Termux, you can install and run `llama.cpp` as if the environment were Linux. Once in the Termux shell:
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```
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$ apt update && apt upgrade -y
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$ apt install git cmake
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```
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Then, follow the [build instructions](https://github.com/ggml-org/llama.cpp/blob/master/docs/build.md), specifically for CMake.
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Once the binaries are built, download your model of choice (e.g., from Hugging Face). It's recommended to place it in the `~/` directory for best performance:
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```
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$ curl -L {model-url} -o ~/{model}.gguf
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```
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Then, if you are not already in the repo directory, `cd` into `llama.cpp` and:
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```
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$ ./build/bin/llama-cli -m ~/{model}.gguf -c {context-size} -p "{your-prompt}"
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```
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Here, we show `llama-cli`, but any of the executables under `examples` should work, in theory. Be sure to set `context-size` to a reasonable number (say, 4096) to start with; otherwise, memory could spike and kill your terminal.
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To see what it might look like visually, here's an old demo of an interactive session running on a Pixel 5 phone:
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https://user-images.githubusercontent.com/271616/225014776-1d567049-ad71-4ef2-b050-55b0b3b9274c.mp4
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## Cross-compile using Android NDK
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It's possible to build `llama.cpp` for Android on your host system via CMake and the Android NDK. If you are interested in this path, ensure you already have an environment prepared to cross-compile programs for Android (i.e., install the Android SDK). Note that, unlike desktop environments, the Android environment ships with a limited set of native libraries, and so only those libraries are available to CMake when building with the Android NDK (see: https://developer.android.com/ndk/guides/stable_apis.)
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Once you're ready and have cloned `llama.cpp`, invoke the following in the project directory:
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```
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$ cmake \
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-DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK/build/cmake/android.toolchain.cmake \
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-DANDROID_ABI=arm64-v8a \
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-DANDROID_PLATFORM=android-28 \
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-DCMAKE_C_FLAGS="-march=armv8.7a" \
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-DCMAKE_CXX_FLAGS="-march=armv8.7a" \
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-DGGML_OPENMP=OFF \
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-DGGML_LLAMAFILE=OFF \
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-B build-android
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```
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Notes:
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- While later versions of Android NDK ship with OpenMP, it must still be installed by CMake as a dependency, which is not supported at this time
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- `llamafile` does not appear to support Android devices (see: https://github.com/Mozilla-Ocho/llamafile/issues/325)
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The above command should configure `llama.cpp` with the most performant options for modern devices. Even if your device is not running `armv8.7a`, `llama.cpp` includes runtime checks for available CPU features it can use.
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Feel free to adjust the Android ABI for your target. Once the project is configured:
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```
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$ cmake --build build-android --config Release -j{n}
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$ cmake --install build-android --prefix {install-dir} --config Release
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```
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After installing, go ahead and download the model of your choice to your host system. Then:
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```
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$ adb shell "mkdir /data/local/tmp/llama.cpp"
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$ adb push {install-dir} /data/local/tmp/llama.cpp/
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$ adb push {model}.gguf /data/local/tmp/llama.cpp/
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$ adb shell
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```
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In the `adb shell`:
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```
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$ cd /data/local/tmp/llama.cpp
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$ LD_LIBRARY_PATH=lib ./bin/llama-simple -m {model}.gguf -c {context-size} -p "{your-prompt}"
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```
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That's it!
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Be aware that Android will not find the library path `lib` on its own, so we must specify `LD_LIBRARY_PATH` in order to run the installed executables. Android does support `RPATH` in later API levels, so this could change in the future. Refer to the previous section for information about `context-size` (very important!) and running other `examples`.
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