Skip to content

Hardware-Aware FP4 FlashAttention-4

Sep 2026 · 2 citations · ⚡ 1 influential
Computer Science

TL;DR

Direct-P is introduced for noncausal inference and a causal path that passes the forward quantization directly into backward into forward quantization is addressed, accelerating a complete single-GPU 8-billion-parameter update by up to 1.14$\times$.

Abstract

Blackwell's 4-bit floating-point (FP4) tensor cores do not automatically make attention faster because softmax conversion and on-chip dependencies dominate once its matrix products shrink. We address this with \emph{Direct-P} for noncausal inference and a causal path that passes the forward quantization directly into backward. Direct-P maps scores directly to FP4 probabilities and reaches up to 2.13$\times$ the bfloat16 (BF16) forward throughput on an NVIDIA GB200. The causal path reconstructs probabilities from saved quantized queries and keys and uses 8-bit floating-point (FP8) gradient operands, accelerating a complete single-GPU 8-billion-parameter update by up to 1.14$\times$. Matched distributed training retains FP8 probabilities and values; every tested MXFP4 probability/value training trajectory diverges.

View source

Similar papers

#machine learning Preprint Sep 2026

Format-Aware Fusion for Fast FP4 Pretraining

Four-bit floating-point (FP4) Tensor Cores accelerate matrix multiplication, but scale computation, operand packing, layout construction, and saved backward state can erase the gain. We present \emph{format-aware fusion}, which co-designs each quantization producer with its scale domain and consumer layout for native \...

R. Hu · 0 citations
#machine learning Preprint Sep 2026

EFQ-Softmax: Exp-Free Quantization for Softmax

EFQ-Softmax (Exp-Free Quantization for Softmax), a low-bit probability-generation method that directly maps shifted attention scores to block-scaled E2M1 operands, is proposed and shown to replace the conventional exp-then-quantize path while preserving end-to-end model quality.

Hao-Hui Han, Yu-Ming Wan, Hong-Ning Wang et al. · 0 citations
#machine learning Preprint Sep 2026

LampAttention: Look-Ahead Mixed-Precision FlashAttention for Dedicated Accelerators

While most attention logits can be computed in low precision without degrading numerical stability, current attention kernels fail to exploit this phenomenon. We introduce a novel hardware-algorithm co-design in the form of mixed-precision FlashAttention. Our method accumulates key-query products and evaluates their ex...

Stanislav S. Budzinskiy, Marian Gloser, T. Yilmaz et al. · 0 citations
Preprint Sep 2026

Efficient FlashAttention on Blackwell via Fixed-Shift Softmax and Persistent Scheduling

On Blackwell, normalization and operand movement can limit attention kernels whose matrix multiplications are already deeply pipelined. We implement an FA4-style pipeline in Triton TLX with fixed-shift dense softmax and a saved inverse denominator for backward. The fixed shift removes recurrent accumulator corrections;...

Олександр Сташук, Hong-Tao Yu, J. Shah · 0 citations
Preprint Sep 2026

PULSE: Unlocking Practical Image Compression on Single-Thread CPU

This work introduces PULSE, a practical codec that enables low-latency decoding on diverse hardware platforms with an ultra-low-complexity 5.2 kMAC/pixel neural receiver, and efficient bit-exact entropy coding with an integer linear CDF predictor and a meta prior.

Zhao-Yang Jia, Tian-Yu Zhang, Zi-Han Zheng et al. · 0 citations

Related blog posts

We use cookies to run the site and, with your consent, for analytics and to show ads. See our Cookie Policy.