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# Gemma 3 with Variable Sliding Window Attention

This guide demonstrates how to deploy google/gemma-3-1b-it with Variable Sliding Window Attention (VSWA) using Dynamo. Since google/gemma-3-1b-it is a small model, each aggregated, decode, or prefill worker only requires one H100 GPU or one GB200 GPU.
VSWA is a mechanism in which a model’s layers alternate between multiple sliding window sizes. An example of this is Gemma 3, which incorporates both global attention layers and sliding window layers.

## Notes
* To run Gemma 3 with VSWA, ensure that the container has TensorRT-LLM v1.0.0rc4 installed.

## Limitation
* The current KV event-based KV routing does not work well with VSWA. The Dynamo team is actively working on adding support to distinguish between events from different layer groups.

### Aggregated Serving
```bash
cd $DYNAMO_HOME/components/backends/trtllm
export MODEL_PATH=google/gemma-3-1b-it
export SERVED_MODEL_NAME=$MODEL_PATH
export AGG_ENGINE_ARGS=engine_configs/gemma3/vswa_agg.yaml
./launch/agg.sh
```

#### Disaggregated Serving
```bash
cd $DYNAMO_HOME/components/backends/trtllm
export MODEL_PATH=google/gemma-3-1b-it
export SERVED_MODEL_NAME=$MODEL_PATH
export PREFILL_ENGINE_ARGS=engine_configs/gemma3/vswa_prefill.yaml
export DECODE_ENGINE_ARGS=engine_configs/gemma3/vswa_decode.yaml
./launch/disagg.sh
```
