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--- |
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library_name: pytorch |
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license: llama2 |
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pipeline_tag: text-generation |
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tags: |
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- llm |
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- generative_ai |
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- quantized |
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- android |
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--- |
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![](https://qaihub-public-assets.s3.us-west-2.amazonaws.com/qai-hub-models/models/llama_v2_7b_chat_quantized/web-assets/model_demo.png) |
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# Llama-v2-7B-Chat: Optimized for Mobile Deployment |
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## State-of-the-art large language model useful on a variety of language understanding and generation tasks |
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Llama 2 is a family of LLMs. The "Chat" at the end indicates that the model is optimized for chatbot-like dialogue. The model is quantized to 4-bit weights and 16-bit activations making it suitable for on-device deployment. For Prompt and output length specified below, the time to first token is Llama-PromptProcessor-Quantized's latency and average time per addition token is Llama-TokenGenerator-KVCache-Quantized's latency. |
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This model is an implementation of Llama-v2-7B-Chat found [here](https://huggingface.co/meta-llama/Llama-2-7b-chat-hf). |
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This repository provides scripts to run Llama-v2-7B-Chat on Qualcomm® devices. |
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More details on model performance across various devices, can be found |
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[here](https://aihub.qualcomm.com/models/llama_v2_7b_chat_quantized). |
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### Model Details |
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- **Model Type:** Text generation |
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- **Model Stats:** |
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- Number of parameters: 7B |
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- Model size: 3.6GB |
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- Model-1 (Prompt Processor): Llama-PromptProcessor-Quantized |
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- Max context length: 1024 |
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- Prompt processor input: 1024 tokens |
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- Prompt processor output: 1024 output tokens + KVCache for token generator |
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- Model-2 (Token Generator): Llama-TokenGenerator-KVCache-Quantized |
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- Token generator input: 1 input token + past KVCache |
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- Token generator output: 1 output token + KVCache for next iteration |
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- Decoding length: 1024 (1 output token + 1023 from KVCache) |
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- Use: Initiate conversation with prompt-processor and then token generator for subsequent iterations. |
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- QNN-SDK: 2.19 |
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## Deploying Llama 2 on-device |
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Large Language Model (LLM) such as [Llama 2](https://llama.meta.com/llama2/) has the following complexities to deploy on-device: |
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1. Model size is too large to fit in device memory for inference |
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2. Multi-Head Attention (MHA) has large activations leading to fallback from accelerators |
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3. High model load and inference time |
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We can tackle the above constraints with the following steps: |
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1. Quantize weights to reduce on-disk model size, e.g., int8 or int4 weights |
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2. Quantize activations to reduce inference time memory pressure |
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3. Graph transformations to reduce inference time memory pressure, e.g., Multi-Head to Split-Head Attention (MHA -> SHA) |
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4. Graph transformations to convert or decompose operations into more accelerator friendly operations e.g. Linear to Conv |
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5. For LLM with 7B or more parameters, above steps are still not good enough on mobile, |
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hence we go one step further and split model into sub-parts. |
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Here, we divide the model into 4 parts in order to |
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1. Make model exportable with low memory usage |
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2. Avoid inference time out-of-memory errors |
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In order to export Llama 2, please ensure |
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1. Host machine has >40GB memory (RAM+swap-space) |
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2. If you don't have enough memory, export.py will dump instructions to increase swap space accordingly |
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| Device | Chipset | Target Runtime | Inference Time (ms) | Peak Memory Range (MB) | Precision | Primary Compute Unit | Target Model |
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| ---|---|---|---|---|---|---|---| |
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| Samsung Galaxy S23 Ultra (Android 13) | Snapdragon® 8 Gen 2 | QNN Model Library | 104.953 ms | 316 - 4785 MB | UINT16 | NPU | Llama-TokenGenerator-KVCache-Quantized |
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| Samsung Galaxy S23 Ultra (Android 13) | Snapdragon® 8 Gen 2 | QNN Model Library | 1917.811 ms | 0 - 1028 MB | UINT16 | NPU | Llama-PromptProcessor-Quantized |
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## Installation |
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This model can be installed as a Python package via pip. |
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```bash |
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pip install "qai-hub-models[llama_v2_7b_chat_quantized]" |
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``` |
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## Configure Qualcomm® AI Hub to run this model on a cloud-hosted device |
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Sign-in to [Qualcomm® AI Hub](https://app.aihub.qualcomm.com/) with your |
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Qualcomm® ID. Once signed in navigate to `Account -> Settings -> API Token`. |
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With this API token, you can configure your client to run models on the cloud |
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hosted devices. |
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```bash |
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qai-hub configure --api_token API_TOKEN |
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``` |
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Navigate to [docs](https://app.aihub.qualcomm.com/docs/) for more information. |
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## Demo off target |
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The package contains a simple end-to-end demo that downloads pre-trained |
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weights and runs this model on a sample input. |
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```bash |
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python -m qai_hub_models.models.llama_v2_7b_chat_quantized.demo |
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``` |
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The above demo runs a reference implementation of pre-processing, model |
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inference, and post processing. |
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**NOTE**: If you want running in a Jupyter Notebook or Google Colab like |
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environment, please add the following to your cell (instead of the above). |
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``` |
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%run -m qai_hub_models.models.llama_v2_7b_chat_quantized.demo |
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``` |
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### Run model on a cloud-hosted device |
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In addition to the demo, you can also run the model on a cloud-hosted Qualcomm® |
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device. This script does the following: |
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* Performance check on-device on a cloud-hosted device |
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* Downloads compiled assets that can be deployed on-device for Android. |
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* Accuracy check between PyTorch and on-device outputs. |
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```bash |
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python -m qai_hub_models.models.llama_v2_7b_chat_quantized.export |
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``` |
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``` |
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Profile Job summary of Llama-TokenGenerator-KVCache-Quantized |
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-------------------------------------------------- |
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Device: Snapdragon X Elite CRD (11) |
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Estimated Inference Time: 118.14 ms |
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Estimated Peak Memory Range: 64.97-64.97 MB |
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Compute Units: NPU (34842) | Total (34842) |
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Profile Job summary of Llama-PromptProcessor-Quantized |
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-------------------------------------------------- |
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Device: Snapdragon X Elite CRD (11) |
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Estimated Inference Time: 2302.57 ms |
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Estimated Peak Memory Range: 10.29-10.29 MB |
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Compute Units: NPU (31766) | Total (31766) |
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``` |
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## Deploying compiled model to Android |
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The models can be deployed using multiple runtimes: |
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- TensorFlow Lite (`.tflite` export): [This |
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tutorial](https://www.tensorflow.org/lite/android/quickstart) provides a |
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guide to deploy the .tflite model in an Android application. |
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- QNN (`.so` export ): This [sample |
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app](https://docs.qualcomm.com/bundle/publicresource/topics/80-63442-50/sample_app.html) |
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provides instructions on how to use the `.so` shared library in an Android application. |
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## View on Qualcomm® AI Hub |
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Get more details on Llama-v2-7B-Chat's performance across various devices [here](https://aihub.qualcomm.com/models/llama_v2_7b_chat_quantized). |
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Explore all available models on [Qualcomm® AI Hub](https://aihub.qualcomm.com/) |
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## License |
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- The license for the original implementation of Llama-v2-7B-Chat can be found |
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[here](https://github.com/facebookresearch/llama/blob/main/LICENSE). |
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- The license for the compiled assets for on-device deployment can be found [here](https://github.com/facebookresearch/llama/blob/main/LICENSE) |
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## References |
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* [LLaMA: Open and Efficient Foundation Language Models](https://arxiv.org/abs/2302.13971) |
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* [Source Model Implementation](https://huggingface.co/meta-llama/Llama-2-7b-chat-hf) |
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## Community |
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* Join [our AI Hub Slack community](https://qualcomm-ai-hub.slack.com/join/shared_invite/zt-2d5zsmas3-Sj0Q9TzslueCjS31eXG2UA#/shared-invite/email) to collaborate, post questions and learn more about on-device AI. |
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* For questions or feedback please [reach out to us](mailto:ai-hub-support@qti.qualcomm.com). |
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