Zyphra ZYFA: FP8 FlashAttention for AMD MI355X, Up to 1.76x Faster

Zyphra released ZYFA, an Apache 2.0 open-source library of FP8 and BF16 prefill attention kernels for AMD Instinct MI355X GPUs (ROCm 7.2.3, PyTorch 2.12) with a drop-in flash_attn_func interface. Its FP8 kernels run 1.16-1.76x faster than AMD's AITER on real model activations, reaching 2,672 TFLOP/s at 32K tokens (53% of FP8 peak), and show 62-78% lower FP8 error than AITER at head dimension 128. ZYFA covers causal prefill forward only, with no decode or paged KV support.