Mistral: Sliding Window Attention with Flash Attention and Sample Packing (#732)

* Implement Mistral FA + SWA + Sample Packing

* Handle unbroadcastable tensor

* chore: lint

* Simplify _prepare_decoder_attention_mask

* Uncomment window size

* Upgrade flash-attn to minimum of 2.3.0 to support SWA

* Add original condition to avoid error during inference

* chore: lint

* use torchscript to prevent oom

* chore: pylint

---------

Co-authored-by: Wing Lian <wing.lian@gmail.com>

setup.py

@@ -46,7 +46,7 @@ setup(
     dependency_links=dependency_links,
     extras_require={
         "flash-attn": [
-            "flash-attn>=2.2.1",
+            "flash-attn>=2.3.0",
         ],
         "deepspeed": [
             "deepspeed",