sglang-flash-attn3

Pre-built Flash Attention 3 (forward-only) CUDA kernels from sgl-flash-attn

Kernel source: kernels-community/sgl-flash-attn3

Usage

pip install kernels

from kernels import get_kernel

fa3 = get_kernel("sgl-project/sgl-flash-attn3", version=1) 

fa3.flash_attn_varlen_func(q, k, v, cu_seqlens_q, cu_seqlens_k, causal=True)
fa3.flash_attn_with_kvcache(q, k_cache, v_cache, cache_seqlens=cache_seqlens, causal=True)
fa3.is_fa3_supported()  # True on H100/H200

Credits

• Tri Dao - Flash Attention 3
• SGLang - sgl_kernel FA3 implementation
• HuggingFace - kernel-builder infrastructure