| # fa4-cute-runtime | |
| Forward-only, SM100-family FlashAttention-4 CuTe DSL package used by FlashRT's | |
| production GROOT N1.7 and PI0.5 Thor runtimes. In addition to the standard | |
| D48/D72/D128 path, it includes the dedicated D256 2CTA forward kernel needed | |
| by PI0.5's PaliGemma encoder. | |
| The package exposes `flash_attn_func`, `flash_attn_varlen_func`, and the | |
| preallocated `forward_static` CUDA Graph entry, including `seqused_k` for | |
| fixed-shape padded K/V. It keeps the vendored | |
| implementation in the private `flashrt_fa4` namespace and vendors the required | |
| quack helper subset, so it cannot replace or mutate upstream `flash_attn` | |
| imports. | |
| See [CARD.md](CARD.md) for usage and [VALIDATION.md](VALIDATION.md) for the | |
| release gate. | |