- keep training attention on dense 4d tensors - use packed 3d tensors with KV cache for inference - extend CUDA rotary embedding to packed 3d inputs - adapt torch, CUDA and FlashAttention backend dispatch Benchmark: NVIDIA L20, BF16, 1B model, paged KV cache, CUDA Graph, prompt 512, generation 128 (median of 3 alternating runs) - batch 1: 234.5 -> 242.6 tok/s (1.034x, +3.4%) - batch 8: 1243.1 -> 1286.6 tok/s (1.035x, +3.5%)